Rather then trying to model the capacitor why not build a reliable clock
and sample the clock before and after the signal you are trying to measure.
In other words you calibrate using a (say) 1 uSec pulse. That would
cover the case of passive parts aging.
On Sat, Feb 15, 2014 at 3:13 PM, Lars
Hi Tom,
I appreciate the offer. I may wind up taking you up on it. But, I'm more
interested in doing the project than getting an interpolator that works; if you
get my meaning. So I'll just plod along at my own speed on this. I may wind
up with questions in the future. I'll address them to
Bob,
I have versions of the picPET that capture an ADC reading along with a
timestamp. I used this with one of Richard's simpler interpolator designs.
There's some info at http://leapsecond.com/pic/picpet2.htm and the projects
aren't final yet but you can contact me or Richard directly.
/tvb
Hi Lars,
I'm lucky in that I'm starting with a PIC running internally at 40MHz. So I
think timing is not going to be a real problem. But after getting a response
from Richard, I'm concerned about flaws in the spice chip models. I'm also a
bit concerned about breadboarding, but come to think
> What Bruce says about interrupts is also worth to check in real life as
> “jitter” due to unexpected interrupts or different timing may give problem.
> In the Arduino GPSDO the timer1 overflow interrupt may delay the 1PPS
> interrupt about 3us and delay the ADC conversion 3us. This is not so c
>>Bob Stewart wrote:
>> Tom tried to steer me to the PICTIC recently, and I sort of brushed him off,
>> because, quite frankly I didn't understand. Now that I've really looked at
>> it, it's a much better idea than using a dsPIC33 and brute-forcing it. But,
>> I don't really need everyth
I think I found the information in the datasheet:
The read operation can be used to read multiple bytes with a
single transfer. When reading bytes from the slave,
the master simply ACKs the data byte if it desires to
read another byte before terminating the transaction.
After the master reads th
Bob Stewart wrote:
Tom tried to steer me to the PICTIC recently, and I sort of brushed him off, because, quite frankly I didn't understand. Now that I've really looked at it, it's a much better idea than using a dsPIC33 and brute-forcing it. But, I don't really need everything the PICTIC offers
michael.c...@sfr.fr said:
> So if you do a multi-byte read to get the lot at once, then it should be
> coherent. I saw some code to do this somewhere, but I have lost track of it.
For things like that, I tend to write some test code to sanity check my
understanding. Then I let it run overnight
Even on the primitive chips that don't have mutlipbyte reads and buffers.
Just read it twice and see it the two reads are the same. On the one in
the thousand case where they differ, read a third time. Problems only
happen if you are so unlucky to read the time just before the seconds flip
ove
Very sad. Looks very similar to the 1200b at this level, the internal oven.
http://www.n4iqt.com/fts1000b/pictures/imag5.jpg
Stanley
- Original Message -
From:
To:
Sent: Friday, February 14, 2014 10:55 AM
Subject: [time-nuts] FTS 2000A
Attached the innards of a FTS 2000A. The unit
At 04:20 PM 2/14/2014, d0ct0r wrote:
hours is the same, but seconds and minutes has changed. Is there any
method to read all three values (HH:MM:SS) by one single requests ?
Or is there any other workaround for this issue ? Or it is not issue
at all ? Thanks !
Sure, read multiple registers (0
I don't think this is an issue. The datasheet indicates :
When reading or writing the time and date registers, secondary
(user) buffers are used to prevent errors when
the internal registers update. When reading the time and
date registers, the user buffers are synchronized to the
internal registe
Read SS MM HH SS and if the first and second readings of SS are within the same
minute you know you have a good reading.
/tvb
- Original Message -
From: "d0ct0r"
To:
Sent: Friday, February 14, 2014 2:20 PM
Subject: [time-nuts] Maxim DS3232 and I2C
>I would like to ask an advise for f
You can improve most old VCOs by removing voltage references derived
from voltage rails and replacing them with REF0x chips.
D.
On Fri, Feb 14, 2014 at 6:35 PM, Tom Knox wrote:
> Hi everyone, some VC oscillators I have played with keep trimmer resistor in
> circuit to adjust the EFC close enoug
Tom tried to steer me to the PICTIC recently, and I sort of brushed him off,
because, quite frankly I didn't understand. Now that I've really looked at it,
it's a much better idea than using a dsPIC33 and brute-forcing it. But, I
don't really need everything the PICTIC offers so I started doin
I've downloaded the flash memory contents from a BC637PCI card, it's a 128K
file but also had to save it as 64K to please the disassemblers I found
online.
That didn't look to be an issue, as far as I can tell only 64K is used
anyway.
The memory chip is a CAT28F010, as opposed to a 29F010 s
I would like to ask an advise for following:
Lets say I have a DS3232 RTC connected by I2C to some MCU. The maximum
allowed I2C bus speed is 400KHZ. And I need to read time (HH:MM:SS) from
it. It will be THREE SEPARATE REQUESTS for each part (hours, minutes and
seconds). My concern: what if I
Hi everyone, some VC oscillators I have played with keep trimmer resistor in
circuit to adjust the EFC close enough for the PLL to work. I was wondering if
changing to more stable resistors could improve ADEV and P/N performance. Also
could this add stability if used to divide the loop voltage.
Those contemplating Arduino TIC's and other such nuttery might like to
investigate
www.makerplot.com
as a VERY convenient, simple interface program for the Arduino. Plots
of temperature etc as well as time constant selection, remote
"pushbutton" contol, etc.etc. without the tedium of GUI programm
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