Re: [time-nuts] frequency generation algorithm.

I did something similar in the Beaglebone Black AM335x PRU. Division is done using a delay loop with variable number of cycles instead of an interrupt. Converting a delay with a fractional amount to integer is essentially a quantization problem. I'm using a triangular PDF dither and first order

[time-nuts] Datum Starloc II GPSDO issues

Another big honkin' wart on DATUM's nose: The unit responds to the standard Trimble TSIP command to select output in UTC or GPS time. But, and I don't like this big but... I cannot deny, it always reports that it is in GPS time mode! You have know way of knowing what kind of time it is

[time-nuts] TU60-D120-131 Specs....?

"@ @ W b 0x01 cksum 0x0D 0x0A" will switch from Motorola mode to Zodiac mode. The checksum is the XOR of all bytes after the @@ and before the cksum byte. The 0x?? values represent binary bytes. The spaces are for clarity and are not sent.

Re: [time-nuts] TU60-D120-131 Specs....?

Thanks Mark, just not getting anything on the terminal program, other than a little square character upon a restart, even tried my PicKit 2 UART tool. Tried both 4800 8N1 and 9600 8N1. Have tried sending @@Cj and a host of other supported commands from the users manual ie @@Ea. Even tried

[time-nuts] Datum Starloc II GPSDO issues

Ok, these things are a little less horrid than they first presented themselves as. Whenever Lady Heather sends a command to change a setting, it follows it up with a command to read that setting back from the receiver. It turns out that the Datum units don't have any (or possible a very

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

p...@heypete.com said: > I have seen those, but I have little experience with PICs and the Wife > Acceptance Factor of buying more stuff for a one-off measurement is low. The PIC family is very similar to AVRs. The picPET and friends are 8 pin DIPs so the Wife is unlikely to notice the

Re: [time-nuts] frequency generation algorithm.

d...@irtelemetrics.com said: > I'm looking for a quick and dirty algorithm or method to generate a pulse > train at arbitrary frequencies based on a fixed clock source. This will be > run as code in a timer ISR in a microcontroller, so some Google for DDS. The hardware implementation is

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

p...@heypete.com said: > I'm a little concerned about the speed at which the pulses need to be > counted. The 32kHz pulses come in every ~30.5 microseconds, and handling an > interrupt on an ATmega328 running at 16MHz takes about 5.125 microseconds[1] Huh? Instruction cycle time is 62.5nS for

Re: [time-nuts] 82357b and TimeLab?

Hello John, thanks, that did the trick - it´s working flawless now! Regards, Matthias, DK4YJ Am 28.06.2016 um 00:32 schrieb John Miles: But TimeLab doesn´t list any GPIB interfaces. Did anyone have success with this combination? Any insights highly appreciated... Agilent's NI488.2

[time-nuts] frequency generation algorithm.

Hi, Quick question to the group, maybe slightly of topic. I'm looking for a quick and dirty algorithm or method to generate a pulse train at arbitrary frequencies based on a fixed clock source. This will be run as code in a timer ISR in a microcontroller, so some calculations can be done.

Re: [time-nuts] Datum Starloc II GPSDO issues

Looks like I have similar StarLoc II. But I bough the item from U.S. Yes, it takes forever to set its location, for some uncertain reason. I did try to change UT module on it. Even using v4 instead of original v2. No luck with this. Its behave the same way. Without that position, the 10Mhz

[time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

Back when that local high school kid was arrested for bringing his "home made" alarm clock to school, I bought a "bomb clock game" off of Ebay. It looks like 7 sticks of dynamite with a circuit board with LEDs strapped to it. The game part is you press a button and it starts counting down 10

[time-nuts] TU60-D120-131 Specs....?

They default to speaking Motorola binary data. The burst of data at power-up is the Motorola @@Cj version info string. You then have to send it some commands to enable various messages. There is a command to enable Zodiac binary mode. I don't think that they speak NMEA.

[time-nuts] Datum Starloc II GPSDO issues

I don't think so. The day and year is there, only the month is 0. They guy selling them has them available in sealed factory case lots. They look new. They are in sealed anti-static bags. My guess is they came from somebody's product line closeout. I did notice that several of their

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

Instead of using a timer and ISR, consider clocking the MCU directly from the external 32 kHz signal. Sample code: http://leapsecond.com/pic/src/pd33.asm It's a $1 solution; acts like a 4-pin, stand-alone, divide-by-32768 counter; works extremely well. /tvb - Original Message - From:

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

On Mon, Jun 27, 2016 at 10:51 PM, Hal Murray wrote: > > I assume you are doing this for fun. That means you get to do whatever you > think will be fun. Indeed, this is strictly for fun. I have strange values for "fun". > The DS3231 is pretty crappy by time nuts

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

Hi Nigel, Using the internal timer as a divide-by-256 counter is a clever way of doing things. Thanks! I'm not familiar with using the timers as an input, so it looks like I need to do some light, relaxing reading of the datasheet. From what I can tell, using timer2 as an input ("asynchronously

Re: [time-nuts] pick and place problems/design

On 28 June 2016 at 00:58, Bob Camp wrote: > I believe I can count the number of projects actually moving forward > on one hand. I hope the increased awareness of how many ways there are to > “build stuff” will significantly increase the number > of projects we all can share in.

Re: [time-nuts] over-determined clock solution

In message , Mark Sims writes: >All timing receivers (including Trimble) calculate an overdetermined >clock solution if more than 4 sats are being tracked (and the signal >meets their TRAIM quality level). But, again, in Trimble-speak,

Re: [time-nuts] Datum Starloc II GPSDO issues

Hi I wonder if these were production line discards rather than pulled from equipment parts? That would explain the missing manufacturing date. They may still have production test code in them rather than final ship code. Bob > On Jun 27, 2016, at 9:32 PM, Mark Sims

Re: [time-nuts] TU60-D120-131 Specs....?

Mark: Is there any trick in getting serial data from these units. I have my terminal program set to 4800 8N1 and the txd and rxd pins on the receiver connected through a TTL/RS232 converter to the PC. Can not get anything on the terminal screen. Scoping the TXD pin on the receiver and I see a

Re: [time-nuts] Impact of GPS antenna height measurments

Tom Van Baak said: "This note is just a plea not to apply the speed-of-light number or the "nanosecond a foot" rule-of-thumb out of context." It works reasonably well as a rule of thumb. It's an upper limit but if you wanted to refine it a bit, divide by two. The average value of sin(x) on

Re: [time-nuts] Impact of GPS antenna height measurments

Yo Tom! On Mon, 27 Jun 2016 15:49:00 -0700 "Tom Van Baak" wrote: > Equating 22 m with 73 ns, or equating 1 foot with 1 ns is only true > in the impossibly rare case of one satellite directly above you. I should have mentioned that I made some simplifying assumptions: The