Perhaps this thread should go off line not to distract from the originators thread. Regards Paul.
On Mon, Apr 21, 2014 at 4:29 PM, paul swed <paulsw...@gmail.com> wrote: > Good afternoon very interested in the work you are doing with the STM > board. > As I mentioned far earlier in this thread I am attempting to use it to > correct the BPSK WWVB signal here. Initial thoughts were using FORTH to > program the STM board. > Very curious what you are using as examples. > My experience in FORTH is from many years ago and have done very poorly at > C. But this may be the case to have something of interest to actually do. > In either language. > Regards > Paul > WB8TSL > > > On Mon, Apr 14, 2014 at 12:27 PM, d0ct0r <t...@patoka.org> wrote: > >> >> >> I was experimenting with the same setup for STM32 MCU. This >> microprocessor has accept the sine wave from external OCXO or GPSDO. No >> problem with this. The only thing: I was need to start MCU from slow >> "watch" crystal first. And then switch it to work to external one. In >> another case I got incorrect timing settings for MCU. Later, I decide to >> implement LTC6957-3 chip to "share" REFCLOCK source, since that chip has >> two equal CMOS-level outputs. >> Unfortunately I have no tool to measure the phase noise and jitters on >> each setup. >> >> >> >> >> It turns out all of this is built into the AVR chip. There is a counter >>> and logic to copy the current counter value to a register on a PPS pulse >>> raising edge. The counter keeps running and every second its value is >>> trapped. >>> >>> I can connect the OCXO and the PPS directly to the AVR pin. The AVR has >>> hardware (a fast comparator) to "square" a low amplitude sine wave and >>> trap >>> the counter on a zero crossing. So it looks like I can get rid of ALL >>> of >>> the external chips. The built in DAC is working well also but it needs >>> some external resisters and caps. >>> >>> No need for '74 FFs or '373' or counter chips. I do get precision >>> timing >>> with no time critical software, no 74xxx chips. >>> >> -- >> WBW, >> >> V.P. >> >> _______________________________________________ >> 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.