GlobalTop Tech FGPMMOPA6H GPS 10Hz 1PPS Module comments


  • PA6H provides 1 PPS (pin 13) after 3-D Fix at 2.8 V (p. 7, 13)
  • 3.3V external antennas may draw up to 28 mA (p.15)
  • Vcc 3.3 V, 25 mA
  • NMEA: GGA, GSA, GSV, RMC, VTG over 2.8 V TTL (p. 17)

Raspberry Pi

NTP server

Adafruit describes the setup using the PA6H GPS module and Raspberry Pi as an NTP server. Note that the Raspberry Pi has 3.3 V logic so level shifters may be necessary to/from the 2.8 V GPS IO.


After setting up the Raspberry Pi UART PySerial can read NMEA with a program such as NMEAutils. The configuration of Raspberry Pi UART in Raspberry Pi 3 vs. older version has been resolved with Raspbian 9 Stretch. The hardware UART connection is to GPIO pins 14 and 15 on the various Raspberry Pi versions.

Red Pitaya


Starting with the Red Pitaya UART Example in C, one could scoop up the NMEA and extract the current time using a 1PPS driven interrupt. Perhaps one could use PySerial to access /dev/ttyPS1 to use the Red Pitaya UART from Python. The Red Pitaya UART electrical connection is to pins 7 and 8 of connector E2.

This would not be for setting the clock accurately like NTP, but rather for determining which second the 1PPS tick occurred at. I used this technique (with different hardware) for the HiST auroral tomography system.