Re: [time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-07 Thread Fabio Eboli
Fabio Eboli ha scritto: Bob Camp ha scritto: The analog TDC is a fine idea. Cheap, easy, Easy for many, not for me. This is why I like the idea to play with the TAC, I have very Here I'm using TAC and TDC for the same meaning... little experience with such high speed stuff, it's like

Re: [time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-07 Thread Fabio Eboli
Bob Camp ha scritto: Hi I believe your second counter (the one that starts on one edge and stops on the other) will have trouble. It is unlikely you will get your 14 ns resolution out of it. Are you thinking to sync logic inside the device or other problems? (not considering "defects" li

Re: [time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-07 Thread Bob Camp
Hi I believe your second counter (the one that starts on one edge and stops on the other) will have trouble. It is unlikely you will get your 14 ns resolution out of it. The analog TDC is a fine idea. Cheap, easy, and requires a few parts that are not built into the micro controller. The simpl

Re: [time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-07 Thread Fabio Eboli
Michael Tharp ha scritto: On 12/6/2012 4:26 AM, Fabio Eboli wrote: Are you using the pll to obtain 72MHz (x9) for the clock? Yes, the crystal oscillator is multiplied up to 72MHz which then drives the timer. Even though the particular timer peripheral I chose happens to be on the APB1 bu

Re: [time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-06 Thread Michael Tharp
On 12/6/2012 4:26 AM, Fabio Eboli wrote: Here are the design documents, if you're curious: http://hg.partiallystapled.com/circuits/serafine/raw-file/d75ab09ca163/out/production.PDF Thank you very much, I will study it with interest, it will be very helpul to see what you have done. Can I ask

Re: [time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-06 Thread Fabio Eboli
Hello Michael! Michael Tharp ha scritto: On 12/05/2012 08:03 AM, Fabio Eboli wrote: I'm seriously thinking to attempt a gpsdo. ... The platform I will try to use is the STM32F103 microcontroller Coincidentally, my previous time-nut project was built around the same chip. I built a simpl

Re: [time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-05 Thread Michael Tharp
On 12/05/2012 08:03 AM, Fabio Eboli wrote: I'm seriously thinking to attempt a gpsdo. It's mainly to learn something new. For some reason I collected some Rb oscillators, and I'd like to have a 10MHz absolute reference, so I will try to discipline one of the Rb, and later maybe an OCXO. The proj

[time-nuts] STM32 based thing (was GPSDO Alternatives)

2012-12-05 Thread Fabio Eboli
Hello, I've written few messages on this mailing list, I'm an absolute beginner on timing science. I've never introduced myself, so this is a sort of introduction... Although this has nothing to do with arduino, reading the post by Chris Albertson about an arduino-based GPSDO, I will share what