Hello fellow time-nuts, My second post to the list. I just wanted to mention that the STM32 GPSDO is a 100% Open Source project, fully documented in the GitHub repository https://github.com/AndrewBCN/STM32-GPSDO and the EEVblog thread https://www.eevblog.com/forum/projects/yet-another-diy-gpsdo-yes-another-one/ . Also some details are available about the firmware in the stm32duino forum thread https://www.stm32duino.com/viewtopic.php?f=10&t=1031
The project has some unique features compared to any other commercial or hobby GPSDO and it is still very much in full swing and actively developed not only by myself but also by a few collaborators. One of the unique features of the STM32 GPSDO is that it uses both a PLL and an FLL. I developed the 100% software FLL around May 2021 and for the PLL I have borrowed Lars Walenius genius TIC design with Erik Kaashoek's modifications (using a 74HC74 instead of a 74HC4046) (WIP). I am also using a picDIV by Tom Van Baak to generate a UTC synchronized PPS (again, WIP). The project can be assembled on a breadboard in one afternoon provided one has all the parts and it works "out of the box". The BOM total cost stands at around 45€ for the basic version and 70€ with all the bells and whistles. The firmware leverages the Arduino programming environment and the hundreds of available libraries, and it is written with the express purpose of being easy to understand, maintain and further develop. It now stands at around 1700 lines of C/C++ code with extensive comments. The main communications channel for this project is the EEVblog thread mentioned above. Greetings from France, Andrew _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
