Re: [time-nuts] PICTIC II ready-made?
There was also the short lived XPLA2 PZ/XCR3320,3960 (Ph/X) SRAM CPLD family, which had to be configured from an external memory... just another exception which confirms the rule. ftp://ftp.xilinx.com/pub/coolpld/isp/960_conf.pdf The even older intel FLEXlogic, bought by Altera, and rebranded FLASHlogic, with the odd CFB/SRAM architecture, had also internal SRAM/Flash configuration memory. In XAPP440 the power-up configuration transfer of Xilinx CPLDs is very briefly mentioned, and in XAPP388 more details for CR-II are provided. Such often overlooked details cold be sometimes crucial... On 4/28/2012 11:46 PM, Bruce Griffiths wrote: Yes, I should have been more specific. The details about the state machine clock behaviour aren't on the datasheet and were obtained by asking Xilinx. The reason for using CMOS RAM to controll the CPLD interconnections is to reduce the static power consumption well below that possible when using EEPROM cells directly. As long as the state machine clock is turned off during normal operation then it will not be a source of timing jitter. I had intended the post as a warning that chip implementation details not necessarily given on the datasheet can be critical for such applications. Bruce MailLists wrote: I guess you wanted to refer to the old XPLA PZ3k/5k CoolRunner series bought from Philips, renamed XCR3k/5k, and later enhanced to XPLA3/XCR3kXL, not the antique FPGA family XC3k... (C)PLDs don't need an external memory for configuration storing, it's internal. There are also some Lattice, ACTEL, and even Xilinx FPGAs with internal non-volatile configuration memory. On 4/28/2012 3:12 PM, Azelio Boriani wrote: configuration is loaded from EEPROM to RAM on power up For every kind of logic? Even for the simplest XC3000 series (and the Altera equivalent EPM3000 series) small EEPROM CPLD? On Sat, Apr 28, 2012 at 9:04 AM, cfoxne...@luna.dyndns.dk wrote: On Fri, 27 Apr 2012 12:03:20 -0700, Jerry Mulchin wrote: You might want to take a look at the Atmel XMEGA parts. Far more capabilities than the ATMega parts. Watch out . If using an Xmega make sure to select the U ... Usb ones. Most of the non U parts have an errata list longer than the datasheet , and in the analog domain they have serious flaws. But going there (smd only) i'd select an arm instead. CFO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
Not true, the configuration is loaded from EEPROM to RAM on power up. Bruce Azelio Boriani wrote: By preload I think you mean the configuration step of the logic. It seems that the Xilinx one stops the clock after the configuration is done. Anyway using small EEPROM based CPLDs you have no clock at all: there is no configuration to load. On Fri, Apr 27, 2012 at 10:01 PM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The Wilkinson TDC (dual slope) has been successfully used for decades in nuclear instrumentation. One problem is in switching the discharge current on and off sufficiently quickly. This can be largely circumvented by having it on all the time. One drawback is the slow conversion speed (100us for a 10,000:1 ratio of charge to discharge current). However they can have superb differential linearity. The problems associated with the jitter associated with an FPGA can be circumvented by using external logic for the critical circuity (synchroniser and current source gating). Using a FET input comparator is advisable to avoid problems (linearity and stability) associated with the comparator input bias current. It may be feasible to implement the synchronisers in a small CPLD, but careful selection to avoid those that use an internal preload state machine whose clock runs continuously and not just during startup will be required. Bruce David wrote: On Fri, 27 Apr 2012 16:30:11 +0200, Attila Kinaliatt...@kinali.ch wrote: On Wed, 25 Apr 2012 23:30:45 -0500 Daviddavidwh...@gmail.com wrote: If you add a second lower current source or sink, then you can get away with a LM311 class comparator and one fast timer channel in the microcontroller. The input pulse width charges the capacitor and the timer counts how long it takes to slowly discharge. Since the conversion is integrating instead of sampling, it has better noise immunity. Yes, a dual slope time strecher would work too. I'm not sure, but i would guess this aproach would be a lot more limited by the noise and device variations. It would be a lot more immune to noise. Both integrating and sampling designs suffer from the same device variations which can be removed through self calibration. Usually a timing input of an uC runs with a counter in the region of 100MHz max, ie +/-5ns resolution. To get to 50ps, one would need to stretch it by a factor of 100 at least, better 1000 to get some headroom for calibration in software. This means that the currents have to have a factor of 1000 in between. Using a charge current somewhere between 10 to 100mA would yield to a discharge current between 10 to 100uA. Keeping the two current sources stabile enough for the ratio to stay stable would be already quite an acheivment. Also keeping the leakage currents at bay would be quite some feat... That is about the performance level of the Tektronix 2440 delay time counter. The counter only runs at 40 MHz but both edges of the 500 MHz sampling clock are used with two integrators so that metastability can be detected and resolved. The charge current is fixed at about 25mA and the discharge current is set during self calibration to maintain a 1250:1 ratio at about 20uA. Stability should not be a problem in the analog design when self calibration is used and that is required at higher performance levels anyway. Even the high offset voltage and bias current of the bipolar technology LM311 only contributes offset and gain error which is how they got away with 100pf of integration capacitance. In contrast to that, a 16bit ADC is dirty cheap and a 24bits are readily available. I haven't had a look at it yet, but if the capacitive charge redistribution ADCs simplifiy the circuitry that much as Bruce has said, then you could get easily 16-18bit resolution. Combine that with a 100MHz reference clock, then you get a nominal resolution 150-40fs(!). Acheiving 10ps resolution should be then a piece of cake and 1ps possible. (yes, i know that 10ps is not that easy...) Charge redistribution ADCs by design have a built in sample and hold which can simplify external circuitry and like delta-sigma converters, they can be built on a digital logic process. In this case, the simplification is in comparison to non-sampling converters where the signal level has to be constant during the conversion cycle for valid results. The advantage with the dual slope design is that it is integrating so high frequency noise is ignored. Controlling noise in a microcontroller sampling ADC even at the 10 bit level is a significant challenge. In a conservative design, I usually start by figuring the loss of one bit do to DNL and another bit do to noise. If you want better performance, the ADC either needs to be integrating or external where noise can be better controlled. I have been looking at a better than 10ps performance design but not primarily for GPS timing
Re: [time-nuts] PICTIC II ready-made?
On Fri, 27 Apr 2012 12:03:20 -0700, Jerry Mulchin wrote: You might want to take a look at the Atmel XMEGA parts. Far more capabilities than the ATMega parts. Watch out . If using an Xmega make sure to select the U ... Usb ones. Most of the non U parts have an errata list longer than the datasheet , and in the analog domain they have serious flaws. But going there (smd only) i'd select an arm instead. CFO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
configuration is loaded from EEPROM to RAM on power up For every kind of logic? Even for the simplest XC3000 series (and the Altera equivalent EPM3000 series) small EEPROM CPLD? On Sat, Apr 28, 2012 at 9:04 AM, cfo xne...@luna.dyndns.dk wrote: On Fri, 27 Apr 2012 12:03:20 -0700, Jerry Mulchin wrote: You might want to take a look at the Atmel XMEGA parts. Far more capabilities than the ATMega parts. Watch out . If using an Xmega make sure to select the U ... Usb ones. Most of the non U parts have an errata list longer than the datasheet , and in the analog domain they have serious flaws. But going there (smd only) i'd select an arm instead. CFO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
I guess you wanted to refer to the old XPLA PZ3k/5k CoolRunner series bought from Philips, renamed XCR3k/5k, and later enhanced to XPLA3/XCR3kXL, not the antique FPGA family XC3k... (C)PLDs don't need an external memory for configuration storing, it's internal. There are also some Lattice, ACTEL, and even Xilinx FPGAs with internal non-volatile configuration memory. On 4/28/2012 3:12 PM, Azelio Boriani wrote: configuration is loaded from EEPROM to RAM on power up For every kind of logic? Even for the simplest XC3000 series (and the Altera equivalent EPM3000 series) small EEPROM CPLD? On Sat, Apr 28, 2012 at 9:04 AM, cfoxne...@luna.dyndns.dk wrote: On Fri, 27 Apr 2012 12:03:20 -0700, Jerry Mulchin wrote: You might want to take a look at the Atmel XMEGA parts. Far more capabilities than the ATMega parts. Watch out . If using an Xmega make sure to select the U ... Usb ones. Most of the non U parts have an errata list longer than the datasheet , and in the analog domain they have serious flaws. But going there (smd only) i'd select an arm instead. CFO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
I have not studied CPLDs but Actel has the only true Flash based FPGAs. The flash cells directly control the FPGA fabric. As such, they are mostly immune to Single Event Upset that plagues just about any other FPGA technology, and there is no configuration step at power up. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Azelio Boriani azelio.bori...@screen.it Sender: time-nuts-boun...@febo.com Date: Sat, 28 Apr 2012 00:57:42 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] PICTIC II ready-made? FPGA with internal flash memory to boot from, yes, but I think that small CPLD haven't to boot anything: they should have the interconnection array associated with the EEPROM cell array. On Fri, Apr 27, 2012 at 11:52 PM, David davidwh...@gmail.com wrote: On Fri, 27 Apr 2012 22:13:55 +0200, Azelio Boriani azelio.bori...@screen.it wrote: By preload I think you mean the configuration step of the logic. It seems that the Xilinx one stops the clock after the configuration is done. Anyway using small EEPROM based CPLDs you have no clock at all: there is no configuration to load. Wouldn't that also apply to an EEPROM based FPGA? I have been thinking that SRAM based devices may be a better match in cases where you only want to have to program one device. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
Yes, I should have been more specific. The details about the state machine clock behaviour aren't on the datasheet and were obtained by asking Xilinx. The reason for using CMOS RAM to controll the CPLD interconnections is to reduce the static power consumption well below that possible when using EEPROM cells directly. As long as the state machine clock is turned off during normal operation then it will not be a source of timing jitter. I had intended the post as a warning that chip implementation details not necessarily given on the datasheet can be critical for such applications. Bruce MailLists wrote: I guess you wanted to refer to the old XPLA PZ3k/5k CoolRunner series bought from Philips, renamed XCR3k/5k, and later enhanced to XPLA3/XCR3kXL, not the antique FPGA family XC3k... (C)PLDs don't need an external memory for configuration storing, it's internal. There are also some Lattice, ACTEL, and even Xilinx FPGAs with internal non-volatile configuration memory. On 4/28/2012 3:12 PM, Azelio Boriani wrote: configuration is loaded from EEPROM to RAM on power up For every kind of logic? Even for the simplest XC3000 series (and the Altera equivalent EPM3000 series) small EEPROM CPLD? On Sat, Apr 28, 2012 at 9:04 AM, cfoxne...@luna.dyndns.dk wrote: On Fri, 27 Apr 2012 12:03:20 -0700, Jerry Mulchin wrote: You might want to take a look at the Atmel XMEGA parts. Far more capabilities than the ATMega parts. Watch out . If using an Xmega make sure to select the U ... Usb ones. Most of the non U parts have an errata list longer than the datasheet , and in the analog domain they have serious flaws. But going there (smd only) i'd select an arm instead. CFO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On 4/28/12 12:10 PM, shali...@gmail.com wrote: I have not studied CPLDs but Actel has the only true Flash based FPGAs. The flash cells directly control the FPGA fabric. As such, they are mostly immune to Single Event Upset that plagues just about any other FPGA technology, and there is no configuration step at power up. .. the flash contents can still be lost(although Actel claims that their flash is pretty neutron and alpha particle immune.. but heavy ions?).. the Actel anti-fuse parts, like the AX and RTAX series, have logic that can't be changed. We use a lot of the Actel flash parts (ProASIC3) for prototyping, then burn it to an rtax for final. I think there's a similar path for the 54SX parts (i.e. a reprogrammable version and an antifuse OTP part) Here's what was in a Brookhaven report about using FPGAs in PHENIX The Actel FPGAs do not have SRAM configuration memory so they are immune to this form of upset. FLASH memories exhibit dissipation of the charge on the floating gate after 20kRad of integrated dose. The dissipation is not permanent damage and is remediated by reprogramming the device. Flash memories also displayed SEE problems during programming during radiation exposure that included gate punch-through, a destructive effect. These types of SEEs are avoided by not programming the FLASH under radiation exposure conditions, namely during machine operation. Practically speaking 20kRad is a fairly decent dose (it's a typical design requirement for a trip to Mars or for GEO).. you pick up about a kRad/year In LEO it's a lot lower (otherwise astronauts in ISS would die). Around Jupiter it's a lot higher (typical design requirements for Europa missions and such are 1 MRad) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
By the way, Actel is now part of Microsemi, with all that it entails. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Jim Lux jim...@earthlink.net Sender: time-nuts-boun...@febo.com Date: Sat, 28 Apr 2012 14:19:40 To: time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] PICTIC II ready-made? On 4/28/12 12:10 PM, shali...@gmail.com wrote: I have not studied CPLDs but Actel has the only true Flash based FPGAs. The flash cells directly control the FPGA fabric. As such, they are mostly immune to Single Event Upset that plagues just about any other FPGA technology, and there is no configuration step at power up. .. the flash contents can still be lost(although Actel claims that their flash is pretty neutron and alpha particle immune.. but heavy ions?).. the Actel anti-fuse parts, like the AX and RTAX series, have logic that can't be changed. We use a lot of the Actel flash parts (ProASIC3) for prototyping, then burn it to an rtax for final. I think there's a similar path for the 54SX parts (i.e. a reprogrammable version and an antifuse OTP part) Here's what was in a Brookhaven report about using FPGAs in PHENIX The Actel FPGAs do not have SRAM configuration memory so they are immune to this form of upset. FLASH memories exhibit dissipation of the charge on the floating gate after 20kRad of integrated dose. The dissipation is not permanent damage and is remediated by reprogramming the device. Flash memories also displayed SEE problems during programming during radiation exposure that included gate punch-through, a destructive effect. These types of SEEs are avoided by not programming the FLASH under radiation exposure conditions, namely during machine operation. Practically speaking 20kRad is a fairly decent dose (it's a typical design requirement for a trip to Mars or for GEO).. you pick up about a kRad/year In LEO it's a lot lower (otherwise astronauts in ISS would die). Around Jupiter it's a lot higher (typical design requirements for Europa missions and such are 1 MRad) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On 4/26/12 10:46 PM, cfo wrote: On Thu, 26 Apr 2012 14:58:26 -0700, Jim Lux wrote: On 4/26/12 1:24 PM, Hal Murray wrote: albertson.ch...@gmail.com said: 2) The IDE is written in Java and is portable. It is truly identical on all platforms. Yes it uses gcc but the end user never has to deal with gcc or even know what gcc is. Same with saving your code, hit just puts it some place and keeps track of it Do I have to use their particular style/GUI? Or can I drive it from make, mixing in pieces I like? How is the documentation on the tool chain and libraries? Are their good man pages? The Arduino IDE is NOT make compatible, as far as I know.. The Arduino IDE is basically an advanced JAVA Editor , that hides avr-gcc for you. The IDE part is that it knows how/where to include/look for the CPP libraries. It's not like a gcc toolchain where you have a separate compiler, linker, binhex, etc and utilities.. It uses a 100% standard avr-gcc toolchain as backend , and just creates the commandline call for using that. So avr-gcc , avr-as , avr-ar , avr-objcopy etc. are used behind the curtains. Fascinating.. Are avr-* also java? Or are there just binary versions that run on all platforms? The other advantage is that there are so many premade/downloadable libraries out there , that you can make : ie. a PID controller wo. knowing much about PID. And you can add a Temp sensor a LCD wo. ever having opened a datasheet. The disadvantage is that due to the hiding/hw-abstraction layer , the generated standard librarycode tends to be slow. But in many cases ie. a DS1820B temp sensor can only make a measurement every 700 ms. So who cares if the 16Mhz was able to query it 1000 times/ sec , in optimized C. But absolutely nothing prevents you to , combine your own Optimized C / asm code , with the arduino libraries. And get the best from both worlds. Very useful to know.. I must say that the IDE hides it very well.. (which I guess means they did a good job... Overall, I'm fairly pleased with the Arduino, although I would like a way to set breakpoints and look at variables for debugging... but hey, printf works) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, 25 Apr 2012 19:17:43 -0300 Daniel Mendes dmend...@gmail.com wrote: About replacing the 74ACT175... there´s a company called Potato Semi (well.. they make chips, right?) whose sole business is to make damn fast 74 logic. Their chips can be bought at ebay in small quantities. Look at this 600MHz D flip flop: http://www.potatosemi.com/potatosemiweb/datasheet/PO74G74A.pdf Hmm... looks interesting. Though, i probably would take standard ECL instead of those because of higher availability (you can get them from mouser, digikey co). But good to know that at least someone is still trying to improve standard 74xx devices, for all those who do not want to use an CPLD/FPGA. Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Fri, 27 Apr 2012 06:21:10 -0700, Jim Lux wrote: It uses a 100% standard avr-gcc toolchain as backend , and just creates the commandline call for using that. So avr-gcc , avr-as , avr-ar , avr-objcopy etc. are used behind the curtains. Fascinating.. Are avr-* also java? Or are there just binary versions that run on all platforms? avr-* is standard gcc (with some AVR specific patches) , at least until you use 4.7.x where many of the AVR specific patches are included in mainstream gcc. avr-gcc should build on all platforms that can build a normal gcc For Win32 i'd recommend WinAVR even though it's a bit old (but it supports the arduino (ATmega328 chip) 100%) I must say that the IDE hides it very well.. (which I guess means they did a good job... Overall, I'm fairly pleased with the Arduino, although I would like a way to set breakpoints and look at variables for debugging... but hey, printf works) I hate the Arduino IDE :-) It hides to much , so i use makefiles and mostly CodeBlocks. But afaik there is a switch in the Arduino 1.0 IDE to enable the gcc/build output so you can see what happens behind the curtain. CFO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Fri, 27 Apr 2012 15:52:33 +0200, Attila Kinali att...@kinali.ch wrote: On Wed, 25 Apr 2012 19:17:43 -0300 Daniel Mendes dmend...@gmail.com wrote: About replacing the 74ACT175... there´s a company called Potato Semi (well.. they make chips, right?) whose sole business is to make damn fast 74 logic. Their chips can be bought at ebay in small quantities. Look at this 600MHz D flip flop: http://www.potatosemi.com/potatosemiweb/datasheet/PO74G74A.pdf Hmm... looks interesting. Though, i probably would take standard ECL instead of those because of higher availability (you can get them from mouser, digikey co). I would like to see some real world test results. They charge $3 per 74G chip plus shipping through their Ebay store so the total price is not much lower than ECL from Mouser or Digikey. But good to know that at least someone is still trying to improve standard 74xx devices, for all those who do not want to use an CPLD/FPGA. I have been going through various papers plus the Xilinx and Altera forums reading about time delay counter design in connection with a project I am working on involving equivalent time and high bandwidth sampling. One of the problems they have with the FPGA and CPLD designs in significant input jitter even before the delay time chain is considered. For best results, all I/Os and other functions have to be inactive during the measurement. One of the papers discussed disabling the LED heartbeat indicator to gain about 50ps of accuracy. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, 25 Apr 2012 23:30:45 -0500 David davidwh...@gmail.com wrote: If you add a second lower current source or sink, then you can get away with a LM311 class comparator and one fast timer channel in the microcontroller. The input pulse width charges the capacitor and the timer counts how long it takes to slowly discharge. Since the conversion is integrating instead of sampling, it has better noise immunity. Yes, a dual slope time strecher would work too. I'm not sure, but i would guess this aproach would be a lot more limited by the noise and device variations. Usually a timing input of an uC runs with a counter in the region of 100MHz max, ie +/-5ns resolution. To get to 50ps, one would need to stretch it by a factor of 100 at least, better 1000 to get some headroom for calibration in software. This means that the currents have to have a factor of 1000 in between. Using a charge current somewhere between 10 to 100mA would yield to a discharge current between 10 to 100uA. Keeping the two current sources stabile enough for the ratio to stay stable would be already quite an acheivment. Also keeping the leakage currents at bay would be quite some feat... In contrast to that, a 16bit ADC is dirty cheap and a 24bits are readily available. I haven't had a look at it yet, but if the capacitive charge redistribution ADCs simplifiy the circuitry that much as Bruce has said, then you could get easily 16-18bit resolution. Combine that with a 100MHz reference clock, then you get a nominal resolution 150-40fs(!). Acheiving 10ps resolution should be then a piece of cake and 1ps possible. (yes, i know that 10ps is not that easy...) Attila Kinali PS: please correct me if i made a wrong assumption somewhere -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
The Altera Max 3000A as I mentioned before will do all TTL devices, it has an extensive library easy to use and very cheap. All That at 200 MHz. I became a believer and others I introduced to it love it to. In an hour from downloading the free software you can have your first design. If I can do it every body can do it. Bert Kehren In a message dated 4/27/2012 9:53:16 A.M. Eastern Daylight Time, att...@kinali.ch writes: On Wed, 25 Apr 2012 19:17:43 -0300 Daniel Mendes dmend...@gmail.com wrote: About replacing the 74ACT175... there´s a company called Potato Semi (well.. they make chips, right?) whose sole business is to make damn fast 74 logic. Their chips can be bought at ebay in small quantities. Look at this 600MHz D flip flop: http://www.potatosemi.com/potatosemiweb/datasheet/PO74G74A.pdf Hmm... looks interesting. Though, i probably would take standard ECL instead of those because of higher availability (you can get them from mouser, digikey co). But good to know that at least someone is still trying to improve standard 74xx devices, for all those who do not want to use an CPLD/FPGA. Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
Hi The ADC input is not quite perfect. There are the usual lumps of inductance here and there and leakage. There's also a bit of a temperature coefficient to the capacitance and some minor voltage dependencies. I think it's likely that your best approach would wind up with something like external NPO cap + ADC rather than just the ADC input. Still it's a cheap / easy thing to do. If you charge with a current around 10 ma, and run a 20 ns max pulse width, that gives you a capacitance of about 60 pf. Running up to 100 ma is certainly possible. Even if the net result is only 12 bits from a 16 bit part, that's still quite good. Of course the real appeal would be to take a 10 bit (often called 12, but they lie) ADC on a uC and maybe get 8 bits from it. If you can start from a 10 to 20 ns pulse, that gets you to below 10 ps. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila Kinali Sent: Friday, April 27, 2012 10:30 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] PICTIC II ready-made? On Wed, 25 Apr 2012 23:30:45 -0500 David davidwh...@gmail.com wrote: If you add a second lower current source or sink, then you can get away with a LM311 class comparator and one fast timer channel in the microcontroller. The input pulse width charges the capacitor and the timer counts how long it takes to slowly discharge. Since the conversion is integrating instead of sampling, it has better noise immunity. Yes, a dual slope time strecher would work too. I'm not sure, but i would guess this aproach would be a lot more limited by the noise and device variations. Usually a timing input of an uC runs with a counter in the region of 100MHz max, ie +/-5ns resolution. To get to 50ps, one would need to stretch it by a factor of 100 at least, better 1000 to get some headroom for calibration in software. This means that the currents have to have a factor of 1000 in between. Using a charge current somewhere between 10 to 100mA would yield to a discharge current between 10 to 100uA. Keeping the two current sources stabile enough for the ratio to stay stable would be already quite an acheivment. Also keeping the leakage currents at bay would be quite some feat... In contrast to that, a 16bit ADC is dirty cheap and a 24bits are readily available. I haven't had a look at it yet, but if the capacitive charge redistribution ADCs simplifiy the circuitry that much as Bruce has said, then you could get easily 16-18bit resolution. Combine that with a 100MHz reference clock, then you get a nominal resolution 150-40fs(!). Acheiving 10ps resolution should be then a piece of cake and 1ps possible. (yes, i know that 10ps is not that easy...) Attila Kinali PS: please correct me if i made a wrong assumption somewhere -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Fri, 27 Apr 2012 16:30:11 +0200, Attila Kinali att...@kinali.ch wrote: On Wed, 25 Apr 2012 23:30:45 -0500 David davidwh...@gmail.com wrote: If you add a second lower current source or sink, then you can get away with a LM311 class comparator and one fast timer channel in the microcontroller. The input pulse width charges the capacitor and the timer counts how long it takes to slowly discharge. Since the conversion is integrating instead of sampling, it has better noise immunity. Yes, a dual slope time strecher would work too. I'm not sure, but i would guess this aproach would be a lot more limited by the noise and device variations. It would be a lot more immune to noise. Both integrating and sampling designs suffer from the same device variations which can be removed through self calibration. Usually a timing input of an uC runs with a counter in the region of 100MHz max, ie +/-5ns resolution. To get to 50ps, one would need to stretch it by a factor of 100 at least, better 1000 to get some headroom for calibration in software. This means that the currents have to have a factor of 1000 in between. Using a charge current somewhere between 10 to 100mA would yield to a discharge current between 10 to 100uA. Keeping the two current sources stabile enough for the ratio to stay stable would be already quite an acheivment. Also keeping the leakage currents at bay would be quite some feat... That is about the performance level of the Tektronix 2440 delay time counter. The counter only runs at 40 MHz but both edges of the 500 MHz sampling clock are used with two integrators so that metastability can be detected and resolved. The charge current is fixed at about 25mA and the discharge current is set during self calibration to maintain a 1250:1 ratio at about 20uA. Stability should not be a problem in the analog design when self calibration is used and that is required at higher performance levels anyway. Even the high offset voltage and bias current of the bipolar technology LM311 only contributes offset and gain error which is how they got away with 100pf of integration capacitance. In contrast to that, a 16bit ADC is dirty cheap and a 24bits are readily available. I haven't had a look at it yet, but if the capacitive charge redistribution ADCs simplifiy the circuitry that much as Bruce has said, then you could get easily 16-18bit resolution. Combine that with a 100MHz reference clock, then you get a nominal resolution 150-40fs(!). Acheiving 10ps resolution should be then a piece of cake and 1ps possible. (yes, i know that 10ps is not that easy...) Charge redistribution ADCs by design have a built in sample and hold which can simplify external circuitry and like delta-sigma converters, they can be built on a digital logic process. In this case, the simplification is in comparison to non-sampling converters where the signal level has to be constant during the conversion cycle for valid results. The advantage with the dual slope design is that it is integrating so high frequency noise is ignored. Controlling noise in a microcontroller sampling ADC even at the 10 bit level is a significant challenge. In a conservative design, I usually start by figuring the loss of one bit do to DNL and another bit do to noise. If you want better performance, the ADC either needs to be integrating or external where noise can be better controlled. I have been looking at a better than 10ps performance design but not primarily for GPS timing applications. I am more interested in equivalent time sampling and high bandwidth sequential or random time sampling. The later can not use an integrating converter because of sampling rate requirements. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
I have been looking at CPLD and FPGA designs for aggregating the logic required but keep running up against their lack of jitter specifications for asynchronous applications. Is the part and development cost worth replacing a handful of discrete logic when the CPLD or FPGA is dedicated to such a small function? I figured I would just have to try a couple of designs and measure how well they do. On Fri, 27 Apr 2012 10:54:57 -0400 (EDT), ewkeh...@aol.com wrote: The Altera Max 3000A as I mentioned before will do all TTL devices, it has an extensive library easy to use and very cheap. All That at 200 MHz. I became a believer and others I introduced to it love it to. In an hour from downloading the free software you can have your first design. If I can do it every body can do it. Bert Kehren In a message dated 4/27/2012 9:53:16 A.M. Eastern Daylight Time, att...@kinali.ch writes: On Wed, 25 Apr 2012 19:17:43 -0300 Daniel Mendes dmend...@gmail.com wrote: About replacing the 74ACT175... there´s a company called Potato Semi (well.. they make chips, right?) whose sole business is to make damn fast 74 logic. Their chips can be bought at ebay in small quantities. Look at this 600MHz D flip flop: http://www.potatosemi.com/potatosemiweb/datasheet/PO74G74A.pdf Hmm... looks interesting. Though, i probably would take standard ECL instead of those because of higher availability (you can get them from mouser, digikey co). But good to know that at least someone is still trying to improve standard 74xx devices, for all those who do not want to use an CPLD/FPGA. Attila Kinali ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
Contact me off list and I will be glad to work with you. Test board etc. Bert Kehren In a message dated 4/27/2012 2:36:45 P.M. Eastern Daylight Time, davidwh...@gmail.com writes: I have been looking at CPLD and FPGA designs for aggregating the logic required but keep running up against their lack of jitter specifications for asynchronous applications. Is the part and development cost worth replacing a handful of discrete logic when the CPLD or FPGA is dedicated to such a small function? I figured I would just have to try a couple of designs and measure how well they do. On Fri, 27 Apr 2012 10:54:57 -0400 (EDT), ewkeh...@aol.com wrote: The Altera Max 3000A as I mentioned before will do all TTL devices, it has an extensive library easy to use and very cheap. All That at 200 MHz. I became a believer and others I introduced to it love it to. In an hour from downloading the free software you can have your first design. If I can do it every body can do it. Bert Kehren In a message dated 4/27/2012 9:53:16 A.M. Eastern Daylight Time, att...@kinali.ch writes: On Wed, 25 Apr 2012 19:17:43 -0300 Daniel Mendes dmend...@gmail.com wrote: About replacing the 74ACT175... there´s a company called Potato Semi (well.. they make chips, right?) whose sole business is to make damn fast 74 logic. Their chips can be bought at ebay in small quantities. Look at this 600MHz D flip flop: http://www.potatosemi.com/potatosemiweb/datasheet/PO74G74A.pdf Hmm... looks interesting. Though, i probably would take standard ECL instead of those because of higher availability (you can get them from mouser, digikey co). But good to know that at least someone is still trying to improve standard 74xx devices, for all those who do not want to use an CPLD/FPGA. Attila Kinali ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
You might want to take a look at the Atmel XMEGA parts. Far more capabilities than the ATMega parts. Brief description: Atmel AVR CPU - Clock speed to 32MHz Memories DMAC - Direct memory access controller Event system System clock and clock options Power management and sleep modes System control and reset Battery backup system WDT - Watchdog timer Interrupts and programmable multilevel interrupt controller PORT - I/O ports TC - 16-bit timer/counters AWeX - Advanced waveform extension Hi-Res - High resolution extension RTC - Real-time counter RTC32 - 32-bit real-time counter USB - Universial serial bus interface TWI - Two-wire serial interface SPI - Serial peripheral interface USART - Universal synchronous and asynchronous serial receiver and transmitter IRCOM - Infrared communication module AES and DES cryptographic engine CRC - Cyclic redundancy check EBI - External bus interface 12-BIT ADC - Analog-to-digital converter 12-BIT DAC - Digital-to-analog converter AC - Analog comparator IEEE 1149.1 JTAG interface PDI - Program and debug interface These parts are a little more than the ATMega parts by a few dollars, but oh so much more capability. Studio 5 is now a very nice IDE to work with albeit for Windows only. But all the same tools that you use under most development environments are useful with the XMega parts as well. Atmel also provides a very nice library for these parts, and works nicely under GNU tools. Just my $0.02 worth. Jerry - N7EME At 04:57 PM 4/25/2012, you wrote: On Wed, Apr 25, 2012 at 4:24 PM, WB6BNQ wb6...@cox.net wrote: Chris, Your undying devotion to the Arduino is laudable. However, the point that i think you are missing is such functionality is also available on other platforms with the same amount of ease and support. If you take someone who has never seen, touched nor had any knowledge of any computing process, then you would find that they would have just as much beginning trouble with the Arduino as any other platform. No, some platforms are harder than others. Building an FPGA powered project at home is harder than writing a Perl script. Using a bare AVR chip is harder then using the same chip inside an Arduino. Try listing all the skills one must learn to make an LED blink on various platforms. You are correct about no platform being perfect. Arduio is not well suited to anything that you are going to manufacture. The unit cost and size are both 10X to high and it lacks enough power for things like signal processing. It is well suited to building one off projects that don't require much compute power. It's advantage is that it makes uP development slightly easier than writing a Perl script. The user does not need to know much. I've used all kinds of computers, Mainframe machines to control radars and uPs to control head movement on a disk drive and I used a Linux system once inside a CCD camera. In this case I thought if the PicTic were to be redone I'd like for it to be hackable by beginners who don't know a lot about TICs or uPs. If you make it to complex people will see it as a black box A true computer NERD would have the ability to flexibly deal with different platforms, as each have their strengths and weaknesses. Thus no one platform is perfect and you chose the one that best fits the project. BillWB6BNQ Chris Albertson wrote: On Wed, Apr 25, 2012 at 12:11 PM, Attila Kinali att...@kinali.ch wrote: On Wed, 25 Apr 2012 08:45:52 -0700 Chris Albertson albertson.ch...@gmail.com wrote: On Wed, Apr 25, 2012 at 5:50 AM, Bill Dailey docdai...@gmail.com wrote: I have wondered the same thing. It might be time for a group project to design a Pictic III that uses parts that are readily available. Today I'd build it around an Arduino rather than a PIC even if the cost is more. Arduino is programmable by __anyone__ and plugs into a USB port, no onwwouldhave to supply programed chips and because it is so easy to program maybe some users would try to make improvements and offer them to others. May i ask what makes the arduino programable by __anyone__ ? Sofar, i only had a look at the hardware of arduino, but never looked at the software side, as for me, who is regularly writing C code for bare metal uC applications, the software part is solved if i know that gcc can generate code for the architecture in question. I can do the same thing too. But there is a steep learning curve for most people. What makes the Arduino easy for beginners is the combination of... 1) A boot loader that makes the Adruino self programmable over USB. No other hardware is required. This also means EVERYONE has the same programming hardware so the software can hide the fact that it is even being used. No settings to figure out 2) The IDE is written in Java and is portable.
Re: [time-nuts] PICTIC II ready-made?
The Wilkinson TDC (dual slope) has been successfully used for decades in nuclear instrumentation. One problem is in switching the discharge current on and off sufficiently quickly. This can be largely circumvented by having it on all the time. One drawback is the slow conversion speed (100us for a 10,000:1 ratio of charge to discharge current). However they can have superb differential linearity. The problems associated with the jitter associated with an FPGA can be circumvented by using external logic for the critical circuity (synchroniser and current source gating). Using a FET input comparator is advisable to avoid problems (linearity and stability) associated with the comparator input bias current. It may be feasible to implement the synchronisers in a small CPLD, but careful selection to avoid those that use an internal preload state machine whose clock runs continuously and not just during startup will be required. Bruce David wrote: On Fri, 27 Apr 2012 16:30:11 +0200, Attila Kinaliatt...@kinali.ch wrote: On Wed, 25 Apr 2012 23:30:45 -0500 Daviddavidwh...@gmail.com wrote: If you add a second lower current source or sink, then you can get away with a LM311 class comparator and one fast timer channel in the microcontroller. The input pulse width charges the capacitor and the timer counts how long it takes to slowly discharge. Since the conversion is integrating instead of sampling, it has better noise immunity. Yes, a dual slope time strecher would work too. I'm not sure, but i would guess this aproach would be a lot more limited by the noise and device variations. It would be a lot more immune to noise. Both integrating and sampling designs suffer from the same device variations which can be removed through self calibration. Usually a timing input of an uC runs with a counter in the region of 100MHz max, ie +/-5ns resolution. To get to 50ps, one would need to stretch it by a factor of 100 at least, better 1000 to get some headroom for calibration in software. This means that the currents have to have a factor of 1000 in between. Using a charge current somewhere between 10 to 100mA would yield to a discharge current between 10 to 100uA. Keeping the two current sources stabile enough for the ratio to stay stable would be already quite an acheivment. Also keeping the leakage currents at bay would be quite some feat... That is about the performance level of the Tektronix 2440 delay time counter. The counter only runs at 40 MHz but both edges of the 500 MHz sampling clock are used with two integrators so that metastability can be detected and resolved. The charge current is fixed at about 25mA and the discharge current is set during self calibration to maintain a 1250:1 ratio at about 20uA. Stability should not be a problem in the analog design when self calibration is used and that is required at higher performance levels anyway. Even the high offset voltage and bias current of the bipolar technology LM311 only contributes offset and gain error which is how they got away with 100pf of integration capacitance. In contrast to that, a 16bit ADC is dirty cheap and a 24bits are readily available. I haven't had a look at it yet, but if the capacitive charge redistribution ADCs simplifiy the circuitry that much as Bruce has said, then you could get easily 16-18bit resolution. Combine that with a 100MHz reference clock, then you get a nominal resolution 150-40fs(!). Acheiving 10ps resolution should be then a piece of cake and 1ps possible. (yes, i know that 10ps is not that easy...) Charge redistribution ADCs by design have a built in sample and hold which can simplify external circuitry and like delta-sigma converters, they can be built on a digital logic process. In this case, the simplification is in comparison to non-sampling converters where the signal level has to be constant during the conversion cycle for valid results. The advantage with the dual slope design is that it is integrating so high frequency noise is ignored. Controlling noise in a microcontroller sampling ADC even at the 10 bit level is a significant challenge. In a conservative design, I usually start by figuring the loss of one bit do to DNL and another bit do to noise. If you want better performance, the ADC either needs to be integrating or external where noise can be better controlled. I have been looking at a better than 10ps performance design but not primarily for GPS timing applications. I am more interested in equivalent time sampling and high bandwidth sequential or random time sampling. The later can not use an integrating converter because of sampling rate requirements. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts
Re: [time-nuts] PICTIC II ready-made?
By preload I think you mean the configuration step of the logic. It seems that the Xilinx one stops the clock after the configuration is done. Anyway using small EEPROM based CPLDs you have no clock at all: there is no configuration to load. On Fri, Apr 27, 2012 at 10:01 PM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The Wilkinson TDC (dual slope) has been successfully used for decades in nuclear instrumentation. One problem is in switching the discharge current on and off sufficiently quickly. This can be largely circumvented by having it on all the time. One drawback is the slow conversion speed (100us for a 10,000:1 ratio of charge to discharge current). However they can have superb differential linearity. The problems associated with the jitter associated with an FPGA can be circumvented by using external logic for the critical circuity (synchroniser and current source gating). Using a FET input comparator is advisable to avoid problems (linearity and stability) associated with the comparator input bias current. It may be feasible to implement the synchronisers in a small CPLD, but careful selection to avoid those that use an internal preload state machine whose clock runs continuously and not just during startup will be required. Bruce David wrote: On Fri, 27 Apr 2012 16:30:11 +0200, Attila Kinaliatt...@kinali.ch wrote: On Wed, 25 Apr 2012 23:30:45 -0500 Daviddavidwh...@gmail.com wrote: If you add a second lower current source or sink, then you can get away with a LM311 class comparator and one fast timer channel in the microcontroller. The input pulse width charges the capacitor and the timer counts how long it takes to slowly discharge. Since the conversion is integrating instead of sampling, it has better noise immunity. Yes, a dual slope time strecher would work too. I'm not sure, but i would guess this aproach would be a lot more limited by the noise and device variations. It would be a lot more immune to noise. Both integrating and sampling designs suffer from the same device variations which can be removed through self calibration. Usually a timing input of an uC runs with a counter in the region of 100MHz max, ie +/-5ns resolution. To get to 50ps, one would need to stretch it by a factor of 100 at least, better 1000 to get some headroom for calibration in software. This means that the currents have to have a factor of 1000 in between. Using a charge current somewhere between 10 to 100mA would yield to a discharge current between 10 to 100uA. Keeping the two current sources stabile enough for the ratio to stay stable would be already quite an acheivment. Also keeping the leakage currents at bay would be quite some feat... That is about the performance level of the Tektronix 2440 delay time counter. The counter only runs at 40 MHz but both edges of the 500 MHz sampling clock are used with two integrators so that metastability can be detected and resolved. The charge current is fixed at about 25mA and the discharge current is set during self calibration to maintain a 1250:1 ratio at about 20uA. Stability should not be a problem in the analog design when self calibration is used and that is required at higher performance levels anyway. Even the high offset voltage and bias current of the bipolar technology LM311 only contributes offset and gain error which is how they got away with 100pf of integration capacitance. In contrast to that, a 16bit ADC is dirty cheap and a 24bits are readily available. I haven't had a look at it yet, but if the capacitive charge redistribution ADCs simplifiy the circuitry that much as Bruce has said, then you could get easily 16-18bit resolution. Combine that with a 100MHz reference clock, then you get a nominal resolution 150-40fs(!). Acheiving 10ps resolution should be then a piece of cake and 1ps possible. (yes, i know that 10ps is not that easy...) Charge redistribution ADCs by design have a built in sample and hold which can simplify external circuitry and like delta-sigma converters, they can be built on a digital logic process. In this case, the simplification is in comparison to non-sampling converters where the signal level has to be constant during the conversion cycle for valid results. The advantage with the dual slope design is that it is integrating so high frequency noise is ignored. Controlling noise in a microcontroller sampling ADC even at the 10 bit level is a significant challenge. In a conservative design, I usually start by figuring the loss of one bit do to DNL and another bit do to noise. If you want better performance, the ADC either needs to be integrating or external where noise can be better controlled. I have been looking at a better than 10ps performance design but not primarily for GPS timing applications. I am more interested in equivalent time sampling and high bandwidth sequential or random time sampling.
Re: [time-nuts] PICTIC II ready-made?
On Sat, 28 Apr 2012 08:01:43 +1200, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The Wilkinson TDC (dual slope) has been successfully used for decades in nuclear instrumentation. One problem is in switching the discharge current on and off sufficiently quickly. This can be largely circumvented by having it on all the time. One drawback is the slow conversion speed (100us for a 10,000:1 ratio of charge to discharge current). However they can have superb differential linearity. All of the designs I have looked at leave the discharge current turned on. The higher resolution ones adjust it during self calibration. I prefer to use integrating converters (charge balancing, single slope, dual slope, and delta-sigma) where possible because of their noise rejection. I actually looked into a GPSDO design using a charge balancing DAC to drive the VCXO because of the low parts count and simplicity. I still may try it. The problems associated with the jitter associated with an FPGA can be circumvented by using external logic for the critical circuity (synchroniser and current source gating). I had already concluded that the clock, trigger, and strobe paths need to be outside the FPGA for minimum jitter. Using a FET input comparator is advisable to avoid problems (linearity and stability) associated with the comparator input bias current. I wonder if substituting an LF311 would be good enough. I am inclined to follow the integrator design from the Tektronix 7T11. It may be feasible to implement the synchronisers in a small CPLD, but careful selection to avoid those that use an internal preload state machine whose clock runs continuously and not just during startup will be required. I will have to watch out for that. Thanks for the warning. One of the FPGA delay chain implementations I read about got down below 50ps with heroic self calibration and mentioned that ANY I/O activity during the measurement significantly reduced the accuracy. David wrote: On Fri, 27 Apr 2012 16:30:11 +0200, Attila Kinaliatt...@kinali.ch wrote: On Wed, 25 Apr 2012 23:30:45 -0500 Daviddavidwh...@gmail.com wrote: If you add a second lower current source or sink, then you can get away with a LM311 class comparator and one fast timer channel in the microcontroller. The input pulse width charges the capacitor and the timer counts how long it takes to slowly discharge. Since the conversion is integrating instead of sampling, it has better noise immunity. Yes, a dual slope time strecher would work too. I'm not sure, but i would guess this aproach would be a lot more limited by the noise and device variations. It would be a lot more immune to noise. Both integrating and sampling designs suffer from the same device variations which can be removed through self calibration. Usually a timing input of an uC runs with a counter in the region of 100MHz max, ie +/-5ns resolution. To get to 50ps, one would need to stretch it by a factor of 100 at least, better 1000 to get some headroom for calibration in software. This means that the currents have to have a factor of 1000 in between. Using a charge current somewhere between 10 to 100mA would yield to a discharge current between 10 to 100uA. Keeping the two current sources stabile enough for the ratio to stay stable would be already quite an acheivment. Also keeping the leakage currents at bay would be quite some feat... That is about the performance level of the Tektronix 2440 delay time counter. The counter only runs at 40 MHz but both edges of the 500 MHz sampling clock are used with two integrators so that metastability can be detected and resolved. The charge current is fixed at about 25mA and the discharge current is set during self calibration to maintain a 1250:1 ratio at about 20uA. Stability should not be a problem in the analog design when self calibration is used and that is required at higher performance levels anyway. Even the high offset voltage and bias current of the bipolar technology LM311 only contributes offset and gain error which is how they got away with 100pf of integration capacitance. In contrast to that, a 16bit ADC is dirty cheap and a 24bits are readily available. I haven't had a look at it yet, but if the capacitive charge redistribution ADCs simplifiy the circuitry that much as Bruce has said, then you could get easily 16-18bit resolution. Combine that with a 100MHz reference clock, then you get a nominal resolution 150-40fs(!). Acheiving 10ps resolution should be then a piece of cake and 1ps possible. (yes, i know that 10ps is not that easy...) Charge redistribution ADCs by design have a built in sample and hold which can simplify external circuitry and like delta-sigma converters, they can be built on a digital logic process. In this case, the simplification is in comparison to non-sampling converters where the signal level has to be
Re: [time-nuts] PICTIC II ready-made?
On Fri, 27 Apr 2012 22:13:55 +0200, Azelio Boriani azelio.bori...@screen.it wrote: By preload I think you mean the configuration step of the logic. It seems that the Xilinx one stops the clock after the configuration is done. Anyway using small EEPROM based CPLDs you have no clock at all: there is no configuration to load. Wouldn't that also apply to an EEPROM based FPGA? I have been thinking that SRAM based devices may be a better match in cases where you only want to have to program one device. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
FPGA with internal flash memory to boot from, yes, but I think that small CPLD haven't to boot anything: they should have the interconnection array associated with the EEPROM cell array. On Fri, Apr 27, 2012 at 11:52 PM, David davidwh...@gmail.com wrote: On Fri, 27 Apr 2012 22:13:55 +0200, Azelio Boriani azelio.bori...@screen.it wrote: By preload I think you mean the configuration step of the logic. It seems that the Xilinx one stops the clock after the configuration is done. Anyway using small EEPROM based CPLDs you have no clock at all: there is no configuration to load. Wouldn't that also apply to an EEPROM based FPGA? I have been thinking that SRAM based devices may be a better match in cases where you only want to have to program one device. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
It uses a 100% standard avr-gcc toolchain as backend , and just creates the commandline call for using that. So avr-gcc , avr-as , avr-ar , avr-objcopy etc. are used behind the curtains. Fascinating.. Are avr-* also java? Or are there just binary versions that run on all platforms? No. gcc is the same old gcc that is written in C and runs and everything. There are binary versions for every platform. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
correct Bert Kehren In a message dated 4/27/2012 6:58:32 P.M. Eastern Daylight Time, azelio.bori...@screen.it writes: FPGA with internal flash memory to boot from, yes, but I think that small CPLD haven't to boot anything: they should have the interconnection array associated with the EEPROM cell array. On Fri, Apr 27, 2012 at 11:52 PM, David davidwh...@gmail.com wrote: On Fri, 27 Apr 2012 22:13:55 +0200, Azelio Boriani azelio.bori...@screen.it wrote: By preload I think you mean the configuration step of the logic. It seems that the Xilinx one stops the clock after the configuration is done. Anyway using small EEPROM based CPLDs you have no clock at all: there is no configuration to load. Wouldn't that also apply to an EEPROM based FPGA? I have been thinking that SRAM based devices may be a better match in cases where you only want to have to program one device. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?...nanode
On 26 April 2012 01:27, Chris Albertson albertson.ch...@gmail.com wrote: http://en.wikipedia.org/wiki/Raspberry_Pi I just read the above page. The Raspberry contains close source drivers and binary blob graphics firmware. That is an 100% deal killer. It's unfortunate that it makes use of binary drivers but Broadcom have a history of not being the best in this respect. However, I'm prepared to put up with this for a 700MHz ARM/Linux SBC for $25+VAT (if you don't need Ethernet). If someone else comes up with, say, a TI OMAP-based board for that price, great... But until then I'm not going to complain when the Broadcom SoC is making this price point possible... As to the GPU firmware — are there many modern GPUs where you get the source to their firmware? Regards, Andrew -- Andrew Back http://carrierdetect.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
Has any one considered asking Richard. As far as logic is concerned a 200 MHz Altera MAX 3000A makes a perfect substitute at a cost of $ 2.50 that includes a very solderable socket. Works Bert Kehren In a message dated 4/25/2012 3:16:51 P.M. Eastern Daylight Time, bruce.griffi...@xtra.co.nz writes: Chris Albertson wrote: On Wed, Apr 25, 2012 at 9:37 AM, Don Lathamd...@montana.com wrote: I forgot to add that a simple redrafting of the II as an Arduino shield with appropriate chips and chip passives would accomplish the desired end without losing the very careful engineering and testing that has already been done? Would be nice to have a way to change caps without soldering as well, maybe just some .1 jumpers? Yes, MOST of the design could be re-used. As an Arduino shield there is no need for a PIC or RS-232 interface becusethe Arduino does that function. You'd need to replace the 74ACT175 part but that is not hard. About changing the cap values without soldering. I guess you could push the leads into a 0.1 inch header strip or install several and use a DIP switch to select which are in. But I don't know if the extra inductance al that wiring adds is enough to worry about. The time to digital converter (TDC) section is merely an interpolator that measures the delay of a synchroniser. The TDC range should be about 2 clock periods to accommodate the range of synchroniser delays and to facilitate calibration. Unless one is changing the synchroniser clock period there is no need to vary the TDC gain. The SR620 uses a similar interpolator and has only a single interpolator range. The range is extended by counting the number of synchroniser clock periods between synchroniser output transitions of interest. When measuring the time interval between 2 signals a pair of synchronisers and interpolators are used. Interpolator nonlinearity can be measured by using a statistical fill the buckets technique which uses nothing but a pair of noisy asynchronous oscillators with high reverse isolation to avoid injection locking. If a suitable ADC is used the interpolator can be simplified considerably whilst improving its performance. Minor nonlinearities are of little significance, as long as they are repeatable and relatively stable they can be easily corrected in software. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
I have a friend who builds and sells power supply units that I designed. He may be interested in building some of these. If I had to guess, he'd be willing to build units and sell them on his web site. Who owns the IP for this project? Maybe we could get some input or direction... Contact me off list for more information... Thanks Dan On 4/25/2012 2:42 PM, time-nuts-requ...@febo.com wrote: Message: 1 Date: Wed, 25 Apr 2012 12:44:30 -0500 From: Stanleytimen...@n4iqt.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] PICTIC II ready-made? Message-ID:4795269806DF49A7B26877D7EB657063@StanleyPC Content-Type: text/plain; format=flowed; charset=iso-8859-1; reply-type=original I still have a supply of boards and most parts including the 74ac175 but no interest in assembly or the kitting process. If someone would like to take this on then I could provide the boards etc ... in bulk. Because of my limited space the kitting process takes several hours to do them one at time :-( Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?...nanode
I tried to find a site to at least get the particulars for the Nanode. Sure it's not a Monode made of doped Nonobtanium? Alan Melia Mmmm not too impressive a web site thoughthe link to the buy page doesnt work backing up to the home the tabs in light grey on a white background are almost unreadabletoo must geewhizz and not the right HF input I suspectstill looks an interesting product. Alan G3NYK - Original Message - From: Andrew Back and...@carrierdetect.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, April 25, 2012 7:39 PM Subject: Re: [time-nuts] PICTIC II ready-made? On 25 April 2012 19:09, Randy D. Hunt randy_hunt...@yahoo.com wrote: Then there is also the matter of surface mount components. Some people my not physically be able to work with them, learning to solder or not. I am rapidly joining that group be cause of my vision. Since Arduino has been mentioned I feel obliged to provide a link for Nanode, an Arduino-compatible that integrates Ethernet and low power wireless (e.g. 868MHz) for around the same price of an Arduino. It's supplied as a kit of through-hole components... http://wiki.london.hackspace.org.uk/view/Project:Nanode Or a nice alternative might be a daughterboard for a Raspberry Pi, which would give you an ARM/Linux base for not much more money, and you could use it to create a standalone system that drives an old monitor for a display. http://en.wikipedia.org/wiki/Raspberry_Pi Regards, Andrew -- Andrew Back http://carrierdetect.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
albertson.ch...@gmail.com said: 2) The IDE is written in Java and is portable. It is truly identical on all platforms. Yes it uses gcc but the end user never has to deal with gcc or even know what gcc is. Same with saving your code, hit just puts it some place and keeps track of it Do I have to use their particular style/GUI? Or can I drive it from make, mixing in pieces I like? How is the documentation on the tool chain and libraries? Are their good man pages? -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On 4/26/12 1:24 PM, Hal Murray wrote: albertson.ch...@gmail.com said: 2) The IDE is written in Java and is portable. It is truly identical on all platforms. Yes it uses gcc but the end user never has to deal with gcc or even know what gcc is. Same with saving your code, hit just puts it some place and keeps track of it Do I have to use their particular style/GUI? Or can I drive it from make, mixing in pieces I like? How is the documentation on the tool chain and libraries? Are their good man pages? The Arduino IDE is NOT make compatible, as far as I know.. The documentation is mostly wiki-like, as well as several books out there. Lots of online forums It's not like a gcc toolchain where you have a separate compiler, linker, binhex, etc and utilities.. It's an *integrated* development environment. If you want a free Java based cross platform IDE that is compatible with make and extensible, etc. look at Eclipse. It's what I use at work for (mostly) C development on Windows, Linux, and RTEMS targets (using cross compilers). It's VERY cool, there's tons of documentation, there's tons of useful plugins for lots of languages and capabilities (cvs, svn, git, etc.) What's nice is that the UI is really the same between my mac laptop, my windows desktop machine, and the linux boxes down in the lab (although, I confess that recently, I've been doing more ssh -X labmachine, because it's hooked up to the target). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Thu, Apr 26, 2012 at 1:24 PM, Hal Murray hmur...@megapathdsl.net wrote: albertson.ch...@gmail.com said: 2) The IDE is written in Java and is portable. It is truly identical on all platforms. Yes it uses gcc but the end user never has to deal with gcc or even know what gcc is. Same with saving your code, hit just puts it some place and keeps track of it Do I have to use their particular style/GUI? Or can I drive it from make, mixing in pieces I like? How is the documentation on the tool chain and libraries? Are their good man pages? The tools are pretty much the standard GCC, and then avrdude. It's all open source. But if you are going to do this your self why not simply use a bare AVR chip? Documentation of the libraries is very good. First their is the Adruino web site which is enough if you already had a preference for tools. Then their are dozens of books you can find. Go to Amazon.com and search for Arduino. Man Pages??? that is a command line thing from the previous century, docs now days are in HTML Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Thu, Apr 26, 2012 at 12:20 PM, Don Latham d...@montana.com wrote: OK, Chris, I'll bite. What the heck is a tool chain? It is the series (or chain) of software tools you need to use. Text editor, compiler, linker and whatever you need to program the chip and then maybe a debugger and maybe version control With Arduino there is no chain got the one Java program. Wellit calls other stuff but most users never notice. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
Hal Murray hmurray@... writes: albertson.chris@... said: 2) The IDE is written in Java and is portable. It is truly identical on all platforms. Yes it uses gcc but the end user never has to deal with gcc or even know what gcc is. Same with saving your code, hit just puts it some place and keeps track of it Do I have to use their particular style/GUI? Or can I drive it from make, mixing in pieces I like? You can use make, as does my project. In fact, I have a system that compiles the bulk of the project twice; once for the Arduino, and once in a simulator harness where I can test things like the PLL response. How is the documentation on the tool chain and libraries? Are their good man pages? The toolchain is of course avr-gcc and avr-binutils, and the library is mostly avr-libc, which is very well documented; the remainder is the Arduino libraries, which are in C++ and have mediocre (but existent, at least) documentation. I'd like to point out that using the Arduino libs is *optional*; while the main target audience certainly will be using them, there's nothing about the hardware that prevents you from writing code in plain C and uploading it, or picking and choosing which parts of a project will make use of the Arduino libs and which will access the bare metal. Again, I've done this with my project. The Serial library is pleasant enough to use; the Ethernet is marginal (no interrupt support, but I had an easier time hacking around that than attempting to rewrite the driver); the timing code is of course useless for my purposes so I stay away from it. I never call attachInterrupt(), which involves a trampoline, but instead declare my own ISRs -- the mixing is mostly unproblematic. It's been pretty pleasant for me overall. Andrew ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On 27 Apr, 2012, at 02:57 , Chris Albertson wrote: Closed source drivers and binary blob firmware.I'd have nothing to do with a project that includes either of those. I'd require a open source platforms with a 100% free tool chain. Also, it is a bit of overkill after all a bare PIC works fine for this application. The only thing binary blob about the Raspberry Pi that I can see seems to be the stuff associated with the graphics accelerator. This is unfortunate, but unless you are into bare-metal programming of high resolution graphics/video (you can do that with an Arduino?) I'm not quite sure how that is relevant. The programming interfaces for all peripherals on the SoC not associated with the GPU seem to be well documented in the Broadcom data sheet: http://www.designspark.com/files/ds/supporting_materials/Broadcom%20BCM2835.pdf I don't know of anything useful which is missing, and I know a port of a non-Linux operating system (NetBSD) to the board is being done using nothing that is non-public. You can leave the graphics binary blob out if you find that offensive and have no use for it anyway. I think the most annoying thing about the Raspberry Pi is that a lot of the GPIO signals aren't brought out to connectors, perhaps to save money on the board. Dennis Ferguson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Thu, 26 Apr 2012 14:58:26 -0700, Jim Lux wrote: On 4/26/12 1:24 PM, Hal Murray wrote: albertson.ch...@gmail.com said: 2) The IDE is written in Java and is portable. It is truly identical on all platforms. Yes it uses gcc but the end user never has to deal with gcc or even know what gcc is. Same with saving your code, hit just puts it some place and keeps track of it Do I have to use their particular style/GUI? Or can I drive it from make, mixing in pieces I like? How is the documentation on the tool chain and libraries? Are their good man pages? The Arduino IDE is NOT make compatible, as far as I know.. The Arduino IDE is basically an advanced JAVA Editor , that hides avr-gcc for you. The IDE part is that it knows how/where to include/look for the CPP libraries. It's not like a gcc toolchain where you have a separate compiler, linker, binhex, etc and utilities.. It uses a 100% standard avr-gcc toolchain as backend , and just creates the commandline call for using that. So avr-gcc , avr-as , avr-ar , avr-objcopy etc. are used behind the curtains. For uploading the program , it uses avrdude. And expects a STK-500 V1 (the old protocol) bootloader to be installed in the chip. Make compatible . Well it's a bit of a challenge to use make , as you have to tell/teach make about the location of the libraries. That the IDE java code already knows about . But it's certainly possible. As i see it : Arduino HW is a standard AVR microprocessor board , that can be used with any editor/compiler. The thing that makes the HW Arduino compatible is the installing of the bootloader. So take any ATmega328 board with a 16Mhz Xtal (The libs expect 16Mhz). Install the bootloader , add a serial interface. And you have an Arduino. The main advantage of the Arduino layout , is that anyone can walk into a RadioSchack and buy one. No soldering required , if one wishes that. As there is a bootloader installed you don't need to have an AVR-ISP programmer , the programming is done via Serial RS-232. So all you need is a COM-Port/ttyxx on your pc. The other advantage is that there are so many premade/downloadable libraries out there , that you can make : ie. a PID controller wo. knowing much about PID. And you can add a Temp sensor a LCD wo. ever having opened a datasheet. The disadvantage is that due to the hiding/hw-abstraction layer , the generated standard librarycode tends to be slow. But in many cases ie. a DS1820B temp sensor can only make a measurement every 700 ms. So who cares if the 16Mhz was able to query it 1000 times/ sec , in optimized C. But absolutely nothing prevents you to , combine your own Optimized C / asm code , with the arduino libraries. And get the best from both worlds. CFO - Denmark (Bingo on AVRFreaks.net) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, 25 Apr 2012 02:01:36 + (UTC) Andrew Rodland and...@cleverdomain.org wrote: Would anyone be willing to sell (or loan for an extended period) one or two ready-to-go PICTIC IIs within the United States? I realize this may be rude to ask since it's a hobby project, but what can I say? All I want it for is to further my own hobby project. Why is it rude to ask? Not everyone can work with a soldering iron. And especially because it is a hobby project, it should be possible to ask whether someone would help out. Just my 0.05CHF Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
I agree, nevertheless let me add: because it is a hobby project it is good also starting to learn how to use the soldering iron. On Wed, Apr 25, 2012 at 2:59 PM, Attila Kinali att...@kinali.ch wrote: On Wed, 25 Apr 2012 02:01:36 + (UTC) Andrew Rodland and...@cleverdomain.org wrote: Would anyone be willing to sell (or loan for an extended period) one or two ready-to-go PICTIC IIs within the United States? I realize this may be rude to ask since it's a hobby project, but what can I say? All I want it for is to further my own hobby project. Why is it rude to ask? Not everyone can work with a soldering iron. And especially because it is a hobby project, it should be possible to ask whether someone would help out. Just my 0.05CHF Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, 25 Apr 2012 15:24:50 +0200 Azelio Boriani azelio.bori...@screen.it wrote: I agree, nevertheless let me add: because it is a hobby project it is good also starting to learn how to use the soldering iron. But for that, you need someone who shows you how to solder. You can learn it yourself, but it takes a lot more time and you waste a lot of electronics... and often you dont even know that the joints aren't good... Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
Yes, better have someone who can help but nothing should prevent you from learning something. On Wed, Apr 25, 2012 at 4:44 PM, Attila Kinali att...@kinali.ch wrote: On Wed, 25 Apr 2012 15:24:50 +0200 Azelio Boriani azelio.bori...@screen.it wrote: I agree, nevertheless let me add: because it is a hobby project it is good also starting to learn how to use the soldering iron. But for that, you need someone who shows you how to solder. You can learn it yourself, but it takes a lot more time and you waste a lot of electronics... and often you dont even know that the joints aren't good... Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, Apr 25, 2012 at 5:50 AM, Bill Dailey docdai...@gmail.com wrote: I have wondered the same thing. It might be time for a group project to design a Pictic III that uses parts that are readily available. Today I'd build it around an Arduino rather than a PIC even if the cost is more. Arduino is programmable by __anyone__ and plugs into a USB port, no onwwouldhave to supply programed chips and because it is so easy to program maybe some users would try to make improvements and offer them to others. Other suggestions to do something like this have come up on this list but then someone starts talking about using some specialized technology that 99.99% of the readers don't know (like FPGAs) I'd like to see it done with 25 cent parts and technology a beginner can master -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
Chris: I concur. Arduino base would allow simple extension to 'net control as well. Don Chris Albertson It might be time for a group project to design a Pictic III that uses parts that are readily available. Today I'd build it around an Arduino rather than a PIC even if the cost is more. Arduino is programmable by __anyone__ and plugs into a USB port, no onwwouldhave to supply programed chips and because it is so easy to program maybe some users would try to make improvements and offer them to others. Other suggestions to do something like this have come up on this list but then someone starts talking about using some specialized technology that 99.99% of the readers don't know (like FPGAs) I'd like to see it done with 25 cent parts and technology a beginner can master -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
I forgot to add that a simple redrafting of the II as an Arduino shield with appropriate chips and chip passives would accomplish the desired end without losing the very careful engineering and testing that has already been done? Would be nice to have a way to change caps without soldering as well, maybe just some .1 jumpers? Don It might be time for a group project to design a Pictic III that uses parts that are readily available. Today I'd build it around an Arduino rather than a PIC even if the cost is more. Arduino is programmable by __anyone__ and plugs into a USB port, no onwwouldhave to supply programed chips and because it is so easy to program maybe some users would try to make improvements and offer them to others. Other suggestions to do something like this have come up on this list but then someone starts talking about using some specialized technology that 99.99% of the readers don't know (like FPGAs) I'd like to see it done with 25 cent parts and technology a beginner can master -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
I still have a supply of boards and most parts including the 74ac175 but no interest in assembly or the kitting process. If someone would like to take this on then I could provide the boards etc ... in bulk. Because of my limited space the kitting process takes several hours to do them one at time :-( Stanley - Original Message - From: Don Latham d...@montana.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, April 25, 2012 11:37 AM Subject: Re: [time-nuts] PICTIC II ready-made? I forgot to add that a simple redrafting of the II as an Arduino shield with appropriate chips and chip passives would accomplish the desired end without losing the very careful engineering and testing that has already been done? Would be nice to have a way to change caps without soldering as well, maybe just some .1 jumpers? Don It might be time for a group project to design a Pictic III that uses parts that are readily available. Today I'd build it around an Arduino rather than a PIC even if the cost is more. Arduino is programmable by __anyone__ and plugs into a USB port, no onwwouldhave to supply programed chips and because it is so easy to program maybe some users would try to make improvements and offer them to others. Other suggestions to do something like this have come up on this list but then someone starts talking about using some specialized technology that 99.99% of the readers don't know (like FPGAs) I'd like to see it done with 25 cent parts and technology a beginner can master -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On 4/25/2012 7:44 AM, Attila Kinali wrote: On Wed, 25 Apr 2012 15:24:50 +0200 Azelio Borianiazelio.bori...@screen.it wrote: I agree, nevertheless let me add: because it is a hobby project it is good also starting to learn how to use the soldering iron. But for that, you need someone who shows you how to solder. You can learn it yourself, but it takes a lot more time and you waste a lot of electronics... and often you dont even know that the joints aren't good... Attila Kinali Then there is also the matter of surface mount components. Some people my not physically be able to work with them, learning to solder or not. I am rapidly joining that group be cause of my vision. Just my 2 cents worth. . . Randy, KI6WAS ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, Apr 25, 2012 at 9:37 AM, Don Latham d...@montana.com wrote: I forgot to add that a simple redrafting of the II as an Arduino shield with appropriate chips and chip passives would accomplish the desired end without losing the very careful engineering and testing that has already been done? Would be nice to have a way to change caps without soldering as well, maybe just some .1 jumpers? Yes, MOST of the design could be re-used. As an Arduino shield there is no need for a PIC or RS-232 interface becusethe Arduino does that function. You'd need to replace the 74ACT175 part but that is not hard. About changing the cap values without soldering. I guess you could push the leads into a 0.1 inch header strip or install several and use a DIP switch to select which are in. But I don't know if the extra inductance al that wiring adds is enough to worry about. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, Apr 25, 2012 at 11:09 AM, Randy D. Hunt randy_hunt...@yahoo.comwrote: Then there is also the matter of surface mount components. Some people my not physically be able to work with them, learning to solder or not. I am rapidly joining that group be cause of my vision. Get yourself a web-cam or an used DV video camera with a firewire cable (Sony had a difference name or it xxxlink maybe?) You may need to add some dioptors to the camera lens (an ordinary magnifying glass works too) and certainly aim a desk lamp at the work. Then you aim the camera straight down and watch the work on a large computer monitor. I can make the smaller chips look 2 inches wide on my screen. It is more comfortable to use the big LCD monitor than a microscope. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On 25 April 2012 19:09, Randy D. Hunt randy_hunt...@yahoo.com wrote: Then there is also the matter of surface mount components. Some people my not physically be able to work with them, learning to solder or not. I am rapidly joining that group be cause of my vision. Since Arduino has been mentioned I feel obliged to provide a link for Nanode, an Arduino-compatible that integrates Ethernet and low power wireless (e.g. 868MHz) for around the same price of an Arduino. It's supplied as a kit of through-hole components... http://wiki.london.hackspace.org.uk/view/Project:Nanode Or a nice alternative might be a daughterboard for a Raspberry Pi, which would give you an ARM/Linux base for not much more money, and you could use it to create a standalone system that drives an old monitor for a display. http://en.wikipedia.org/wiki/Raspberry_Pi Regards, Andrew -- Andrew Back http://carrierdetect.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, Apr 25, 2012 at 11:39 AM, Andrew Back and...@carrierdetect.comwrote: On 25 April 2012 19:09, Randy D. Hunt randy_hunt...@yahoo.com wrote: Then there is also the matter of surface mount components. Some people my not physically be able to work with them, learning to solder or not. I am rapidly joining that group be cause of my vision. Since Arduino has been mentioned I feel obliged to provide a link for Nanode, an Arduino-compatible that integrates Ethernet and low power wireless (e.g. 868MHz) for around the same price of an Arduino. It's supplied as a kit of through-hole components... Looks good, the advantage of Arduino is that compatible units are available from multiple sources in the US, Europe and Asia. You are not locked into a single supplier. The other good thing is the very easy development environs meant that runs under Windows, Mac OS and Linus pretty much identically and it is easy enough to use for beginners I'm a fan of using Linux too. but for stuff like this a bare uP with no OS usually gives better real-time performance. I've used real-time versions of Linux that do give you access to the bare hardware. But as much as I like it, real-time Linux on ARM or the like is hardly a beginner friendly environment. One has to know quite a lot got to get started. One important goal for most hobbyists is to learn something. So it should be SIMPLE so more people can understand it.IMO, firmware written in assembly language and real-time OSes don't pass the test for simple. You really have to have discipline and resist the for a little more money we could do feature creep I like the physical size of the Arduino shield too. It is so small that there is no room of feature creep without resorting to SMT parts. Then if some one really wants to add signal conditioning they can stack on a second shield, kind of a lego-like design with the micro controller as the base layer. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, 25 Apr 2012 08:45:52 -0700 Chris Albertson albertson.ch...@gmail.com wrote: On Wed, Apr 25, 2012 at 5:50 AM, Bill Dailey docdai...@gmail.com wrote: I have wondered the same thing. It might be time for a group project to design a Pictic III that uses parts that are readily available. Today I'd build it around an Arduino rather than a PIC even if the cost is more. Arduino is programmable by __anyone__ and plugs into a USB port, no onwwouldhave to supply programed chips and because it is so easy to program maybe some users would try to make improvements and offer them to others. May i ask what makes the arduino programable by __anyone__ ? Sofar, i only had a look at the hardware of arduino, but never looked at the software side, as for me, who is regularly writing C code for bare metal uC applications, the software part is solved if i know that gcc can generate code for the architecture in question. Other suggestions to do something like this have come up on this list but then someone starts talking about using some specialized technology that 99.99% of the readers don't know (like FPGAs) I'd like to see it done with 25 cent parts and technology a beginner can master The thing is, we want to get into a region of mesurment precision, that requires good and high quality devices and/or heavy post processing. Most of the devices needed are pretty advanced. A PICTIC II like Nutt Interpolator can be build using a higher frequency XO with lower jitter and using higher quality components (eg ECL devices instead of 74HC, or better ADCs) which could lead to a magnitude or two of precision enhancement. But these devices are not as easy to handle as the ones used in the PICTIC II. They would be all SMD with smaller pitch than 1.27mm (mostly 0.63mm, some 0.5mm), nothing you'd solder by hand if you have not at least some experience and an either a good sight or a microscope or similar. On the other hand, i am pretty sure that a 100 pieces production run could be done with all the interest on this mailinglist. And with that you'd get probably below 100USD for a PICTIC II like system. Even if using more expensive components. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
Chris Albertson wrote: On Wed, Apr 25, 2012 at 9:37 AM, Don Lathamd...@montana.com wrote: I forgot to add that a simple redrafting of the II as an Arduino shield with appropriate chips and chip passives would accomplish the desired end without losing the very careful engineering and testing that has already been done? Would be nice to have a way to change caps without soldering as well, maybe just some .1 jumpers? Yes, MOST of the design could be re-used. As an Arduino shield there is no need for a PIC or RS-232 interface becusethe Arduino does that function. You'd need to replace the 74ACT175 part but that is not hard. About changing the cap values without soldering. I guess you could push the leads into a 0.1 inch header strip or install several and use a DIP switch to select which are in. But I don't know if the extra inductance al that wiring adds is enough to worry about. The time to digital converter (TDC) section is merely an interpolator that measures the delay of a synchroniser. The TDC range should be about 2 clock periods to accommodate the range of synchroniser delays and to facilitate calibration. Unless one is changing the synchroniser clock period there is no need to vary the TDC gain. The SR620 uses a similar interpolator and has only a single interpolator range. The range is extended by counting the number of synchroniser clock periods between synchroniser output transitions of interest. When measuring the time interval between 2 signals a pair of synchronisers and interpolators are used. Interpolator nonlinearity can be measured by using a statistical fill the buckets technique which uses nothing but a pair of noisy asynchronous oscillators with high reverse isolation to avoid injection locking. If a suitable ADC is used the interpolator can be simplified considerably whilst improving its performance. Minor nonlinearities are of little significance, as long as they are repeatable and relatively stable they can be easily corrected in software. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
If you guys go the PIC route, I'm always happy to burn them for the group for cheap. I think in the past I was doing 5 bucks for the first one (including delivery) plus $2.50 for each additional. I still have a ton of those plastic chip tubes for mailing them so the pins don't get bent. -Bob On Wed, Apr 25, 2012 at 11:44 AM, Stanley timen...@n4iqt.com wrote: I still have a supply of boards and most parts including the 74ac175 but no interest in assembly or the kitting process. If someone would like to take this on then I could provide the boards etc ... in bulk. Because of my limited space the kitting process takes several hours to do them one at time :-( Stanley - Original Message - From: Don Latham d...@montana.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, April 25, 2012 11:37 AM Subject: Re: [time-nuts] PICTIC II ready-made? I forgot to add that a simple redrafting of the II as an Arduino shield with appropriate chips and chip passives would accomplish the desired end without losing the very careful engineering and testing that has already been done? Would be nice to have a way to change caps without soldering as well, maybe just some .1 jumpers? Don It might be time for a group project to design a Pictic III that uses parts that are readily available. Today I'd build it around an Arduino rather than a PIC even if the cost is more. Arduino is programmable by __anyone__ and plugs into a USB port, no onwwouldhave to supply programed chips and because it is so easy to program maybe some users would try to make improvements and offer them to others. Other suggestions to do something like this have come up on this list but then someone starts talking about using some specialized technology that 99.99% of the readers don't know (like FPGAs) I'd like to see it done with 25 cent parts and technology a beginner can master -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
Attila Kinali wrote: Hi Bruce, On Thu, 26 Apr 2012 07:15:41 +1200 Bruce Griffithsbruce.griffi...@xtra.co.nz wrote: If a suitable ADC is used the interpolator can be simplified considerably whilst improving its performance. Could you tell a little bit more about what a suitable ADC for a time interpolator is? And how exactly does it help to simplify the interpolator? Attila Kinali If a capacitive input charge redistribution ADC is used the interpolator output capacitor can be directly connected to it. This eliminates the output buffer amp with its unknown settling time as well as the associated gain and offset adjustements. The TDC capacitor merely acts as temporary charge storage to ensure the ADC input voltage limits arent exceeded during the charging phase. The charge is redistributed between the external capacitor and the ADC sampling capacitance with a time constant set the ADC sampling switch on resistance. All the calibration adjustments can be eliminated and replaced by software calibration if reasonably close tolerance parts are used. Most of the ADCs built into current microprocessors are capacitive input charge redistribution ADCs. One just needs to ensure that the ADC input leakage current is sufficiently small. The specified pin leakage current test limits are considerably higher than the actual leakage. If an external ADC is used higher resolution is possible. The addition of a ground plane to the PCB should also improve the perfformance. The current source also needs a little tweaking (high frequency decoupling of the transistor emitter and base from the opamp) to improve its transient response. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Thu, 26 Apr 2012 08:00:17 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: If a capacitive input charge redistribution ADC is used the interpolator output capacitor can be directly connected to it. This eliminates the output buffer amp with its unknown settling time as well as the associated gain and offset adjustements. Quite interesting... Thanks a lot! Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
About replacing the 74ACT175... there´s a company called Potato Semi (well.. they make chips, right?) whose sole business is to make damn fast 74 logic. Their chips can be bought at ebay in small quantities. Look at this 600MHz D flip flop: http://www.potatosemi.com/potatosemiweb/datasheet/PO74G74A.pdf Daniel Em 25/04/2012 16:15, Bruce Griffiths escreveu: Chris Albertson wrote: On Wed, Apr 25, 2012 at 9:37 AM, Don Lathamd...@montana.com wrote: I forgot to add that a simple redrafting of the II as an Arduino shield with appropriate chips and chip passives would accomplish the desired end without losing the very careful engineering and testing that has already been done? Would be nice to have a way to change caps without soldering as well, maybe just some .1 jumpers? Yes, MOST of the design could be re-used. As an Arduino shield there is no need for a PIC or RS-232 interface becusethe Arduino does that function. You'd need to replace the 74ACT175 part but that is not hard. About changing the cap values without soldering. I guess you could push the leads into a 0.1 inch header strip or install several and use a DIP switch to select which are in. But I don't know if the extra inductance al that wiring adds is enough to worry about. The time to digital converter (TDC) section is merely an interpolator that measures the delay of a synchroniser. The TDC range should be about 2 clock periods to accommodate the range of synchroniser delays and to facilitate calibration. Unless one is changing the synchroniser clock period there is no need to vary the TDC gain. The SR620 uses a similar interpolator and has only a single interpolator range. The range is extended by counting the number of synchroniser clock periods between synchroniser output transitions of interest. When measuring the time interval between 2 signals a pair of synchronisers and interpolators are used. Interpolator nonlinearity can be measured by using a statistical fill the buckets technique which uses nothing but a pair of noisy asynchronous oscillators with high reverse isolation to avoid injection locking. If a suitable ADC is used the interpolator can be simplified considerably whilst improving its performance. Minor nonlinearities are of little significance, as long as they are repeatable and relatively stable they can be easily corrected in software. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, Apr 25, 2012 at 12:11 PM, Attila Kinali att...@kinali.ch wrote: On Wed, 25 Apr 2012 08:45:52 -0700 Chris Albertson albertson.ch...@gmail.com wrote: On Wed, Apr 25, 2012 at 5:50 AM, Bill Dailey docdai...@gmail.com wrote: I have wondered the same thing. It might be time for a group project to design a Pictic III that uses parts that are readily available. Today I'd build it around an Arduino rather than a PIC even if the cost is more. Arduino is programmable by __anyone__ and plugs into a USB port, no onwwouldhave to supply programed chips and because it is so easy to program maybe some users would try to make improvements and offer them to others. May i ask what makes the arduino programable by __anyone__ ? Sofar, i only had a look at the hardware of arduino, but never looked at the software side, as for me, who is regularly writing C code for bare metal uC applications, the software part is solved if i know that gcc can generate code for the architecture in question. I can do the same thing too. But there is a steep learning curve for most people. What makes the Arduino easy for beginners is the combination of... 1) A boot loader that makes the Adruino self programmable over USB. No other hardware is required. This also means EVERYONE has the same programming hardware so the software can hide the fact that it is even being used. No settings to figure out 2) The IDE is written in Java and is portable. It is truly identical on all platforms. Yes it uses gcc but the end user never has to deal with gcc or even know what gcc is. Same with saving your code, hit just puts it some place and keeps track of it 3) There is a library of functions that work together. and the library is the SAME on even Arduino so all the example code just works. you can cut and paste code between projects. Most people when they write programs are really stringing together library calls. So it takes two lines of code to get the value from an ADC and send it over USB to a PC. 4) There are lot of books and on-line training materials and all the examples work on all platforms and on all Arduino compatible devices. 5) it is fast. I can change a line of code and then hit the load button and seconds later the changed code is running on the Arduino. It is almost like programming an interpreted language 6) The whole system was designed so that artists and designers could us microcontrollersin their projects. The first test project I did was to read the voltage from the wiper on a 100K pot and display it on an LCD screen. It took a little over an hour and that included wiring up the hardware, plugging the Arduino into the computer. Then I unplug the USB cable and connect a 9V battery and I have a portable toy project. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
Chris, Your undying devotion to the Arduino is laudable. However, the point that i think you are missing is such functionality is also available on other platforms with the same amount of ease and support. If you take someone who has never seen, touched nor had any knowledge of any computing process, then you would find that they would have just as much beginning trouble with the Arduino as any other platform. A true computer NERD would have the ability to flexibly deal with different platforms, as each have their strengths and weaknesses. Thus no one platform is perfect and you chose the one that best fits the project. BillWB6BNQ Chris Albertson wrote: On Wed, Apr 25, 2012 at 12:11 PM, Attila Kinali att...@kinali.ch wrote: On Wed, 25 Apr 2012 08:45:52 -0700 Chris Albertson albertson.ch...@gmail.com wrote: On Wed, Apr 25, 2012 at 5:50 AM, Bill Dailey docdai...@gmail.com wrote: I have wondered the same thing. It might be time for a group project to design a Pictic III that uses parts that are readily available. Today I'd build it around an Arduino rather than a PIC even if the cost is more. Arduino is programmable by __anyone__ and plugs into a USB port, no onwwouldhave to supply programed chips and because it is so easy to program maybe some users would try to make improvements and offer them to others. May i ask what makes the arduino programable by __anyone__ ? Sofar, i only had a look at the hardware of arduino, but never looked at the software side, as for me, who is regularly writing C code for bare metal uC applications, the software part is solved if i know that gcc can generate code for the architecture in question. I can do the same thing too. But there is a steep learning curve for most people. What makes the Arduino easy for beginners is the combination of... 1) A boot loader that makes the Adruino self programmable over USB. No other hardware is required. This also means EVERYONE has the same programming hardware so the software can hide the fact that it is even being used. No settings to figure out 2) The IDE is written in Java and is portable. It is truly identical on all platforms. Yes it uses gcc but the end user never has to deal with gcc or even know what gcc is. Same with saving your code, hit just puts it some place and keeps track of it 3) There is a library of functions that work together. and the library is the SAME on even Arduino so all the example code just works. you can cut and paste code between projects. Most people when they write programs are really stringing together library calls. So it takes two lines of code to get the value from an ADC and send it over USB to a PC. 4) There are lot of books and on-line training materials and all the examples work on all platforms and on all Arduino compatible devices. 5) it is fast. I can change a line of code and then hit the load button and seconds later the changed code is running on the Arduino. It is almost like programming an interpreted language 6) The whole system was designed so that artists and designers could us microcontrollersin their projects. The first test project I did was to read the voltage from the wiper on a 100K pot and display it on an LCD screen. It took a little over an hour and that included wiring up the hardware, plugging the Arduino into the computer. Then I unplug the USB cable and connect a 9V battery and I have a portable toy project. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?...nanode
Mmmm not too impressive a web site thoughthe link to the buy page doesnt work backing up to the home the tabs in light grey on a white background are almost unreadabletoo must geewhizz and not the right HF input I suspectstill looks an interesting product. Alan G3NYK - Original Message - From: Andrew Back and...@carrierdetect.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, April 25, 2012 7:39 PM Subject: Re: [time-nuts] PICTIC II ready-made? On 25 April 2012 19:09, Randy D. Hunt randy_hunt...@yahoo.com wrote: Then there is also the matter of surface mount components. Some people my not physically be able to work with them, learning to solder or not. I am rapidly joining that group be cause of my vision. Since Arduino has been mentioned I feel obliged to provide a link for Nanode, an Arduino-compatible that integrates Ethernet and low power wireless (e.g. 868MHz) for around the same price of an Arduino. It's supplied as a kit of through-hole components... http://wiki.london.hackspace.org.uk/view/Project:Nanode Or a nice alternative might be a daughterboard for a Raspberry Pi, which would give you an ARM/Linux base for not much more money, and you could use it to create a standalone system that drives an old monitor for a display. http://en.wikipedia.org/wiki/Raspberry_Pi Regards, Andrew -- Andrew Back http://carrierdetect.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, Apr 25, 2012 at 4:24 PM, WB6BNQ wb6...@cox.net wrote: Chris, Your undying devotion to the Arduino is laudable. However, the point that i think you are missing is such functionality is also available on other platforms with the same amount of ease and support. If you take someone who has never seen, touched nor had any knowledge of any computing process, then you would find that they would have just as much beginning trouble with the Arduino as any other platform. No, some platforms are harder than others. Building an FPGA powered project at home is harder than writing a Perl script. Using a bare AVR chip is harder then using the same chip inside an Arduino. Try listing all the skills one must learn to make an LED blink on various platforms. You are correct about no platform being perfect. Arduio is not well suited to anything that you are going to manufacture. The unit cost and size are both 10X to high and it lacks enough power for things like signal processing. It is well suited to building one off projects that don't require much compute power. It's advantage is that it makes uP development slightly easier than writing a Perl script. The user does not need to know much. I've used all kinds of computers, Mainframe machines to control radars and uPs to control head movement on a disk drive and I used a Linux system once inside a CCD camera. In this case I thought if the PicTic were to be redone I'd like for it to be hackable by beginners who don't know a lot about TICs or uPs. If you make it to complex people will see it as a black box A true computer NERD would have the ability to flexibly deal with different platforms, as each have their strengths and weaknesses. Thus no one platform is perfect and you chose the one that best fits the project. BillWB6BNQ Chris Albertson wrote: On Wed, Apr 25, 2012 at 12:11 PM, Attila Kinali att...@kinali.ch wrote: On Wed, 25 Apr 2012 08:45:52 -0700 Chris Albertson albertson.ch...@gmail.com wrote: On Wed, Apr 25, 2012 at 5:50 AM, Bill Dailey docdai...@gmail.com wrote: I have wondered the same thing. It might be time for a group project to design a Pictic III that uses parts that are readily available. Today I'd build it around an Arduino rather than a PIC even if the cost is more. Arduino is programmable by __anyone__ and plugs into a USB port, no onwwouldhave to supply programed chips and because it is so easy to program maybe some users would try to make improvements and offer them to others. May i ask what makes the arduino programable by __anyone__ ? Sofar, i only had a look at the hardware of arduino, but never looked at the software side, as for me, who is regularly writing C code for bare metal uC applications, the software part is solved if i know that gcc can generate code for the architecture in question. I can do the same thing too. But there is a steep learning curve for most people. What makes the Arduino easy for beginners is the combination of... 1) A boot loader that makes the Adruino self programmable over USB. No other hardware is required. This also means EVERYONE has the same programming hardware so the software can hide the fact that it is even being used. No settings to figure out 2) The IDE is written in Java and is portable. It is truly identical on all platforms. Yes it uses gcc but the end user never has to deal with gcc or even know what gcc is. Same with saving your code, hit just puts it some place and keeps track of it 3) There is a library of functions that work together. and the library is the SAME on even Arduino so all the example code just works. you can cut and paste code between projects. Most people when they write programs are really stringing together library calls. So it takes two lines of code to get the value from an ADC and send it over USB to a PC. 4) There are lot of books and on-line training materials and all the examples work on all platforms and on all Arduino compatible devices. 5) it is fast. I can change a line of code and then hit the load button and seconds later the changed code is running on the Arduino. It is almost like programming an interpreted language 6) The whole system was designed so that artists and designers could us microcontrollersin their projects. The first test project I did was to read the voltage from the wiper on a 100K pot and display it on an LCD screen. It took a little over an hour and that included wiring up the hardware, plugging the Arduino into the computer. Then I unplug the USB cable and connect a 9V battery and I have a portable toy project. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
Re: [time-nuts] PICTIC II ready-made?
two thumbs up for Radio Shack - they sure have their problems but they are all we have in a lot of places. with the new Velleman and Arduino and Basic Stamp kits, they are clearly trying. they have a ways to go, but I try to vote with my $$$ a little bit. Cliff K6CLS On 2012-04-25 16:41, Bill Dailey wrote: Rasberry pi appears to have fallen victim to poor pre market research. Essentially vapor for now. Don't know when you can get one. I have been looking to get one since march. RadioShack carries arduino. Doc KX0O ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, 25 Apr 2012 11:13:42 -0700, Chris Albertson albertson.ch...@gmail.com wrote: On Wed, Apr 25, 2012 at 9:37 AM, Don Latham d...@montana.com wrote: I forgot to add that a simple redrafting of the II as an Arduino shield with appropriate chips and chip passives would accomplish the desired end without losing the very careful engineering and testing that has already been done? Would be nice to have a way to change caps without soldering as well, maybe just some .1 jumpers? Yes, MOST of the design could be re-used. As an Arduino shield there is no need for a PIC or RS-232 interface becusethe Arduino does that function. You'd need to replace the 74ACT175 part but that is not hard. About changing the cap values without soldering. I guess you could push the leads into a 0.1 inch header strip or install several and use a DIP switch to select which are in. But I don't know if the extra inductance al that wiring adds is enough to worry about. One problem with the design in this case is that it requires 8 or 9 I/O pins making the use of additional Arduino shields difficult. Would you add tri-state buffering and a chip select? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PICTIC II ready-made?
On Wed, 25 Apr 2012 21:26:25 +0200, Attila Kinali att...@kinali.ch wrote: Hi Bruce, On Thu, 26 Apr 2012 07:15:41 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: If a suitable ADC is used the interpolator can be simplified considerably whilst improving its performance. Could you tell a little bit more about what a suitable ADC for a time interpolator is? And how exactly does it help to simplify the interpolator? If you add a second lower current source or sink, then you can get away with a LM311 class comparator and one fast timer channel in the microcontroller. The input pulse width charges the capacitor and the timer counts how long it takes to slowly discharge. Since the conversion is integrating instead of sampling, it has better noise immunity. The Tektronix 2440 uses this technique to get about 50ps resolution. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
