Hi! If it is all the same for you, I prefer this thread continue "in the open" as I am interested both in using an Arduino-like for my first GPSDO and STM32 for event capture and timming.
Regards, Edésio On Mon, Apr 21, 2014 at 04:29:35PM -0400, paul swed 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 <[email protected]> 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 -- [email protected] > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > > mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
