GlobalTop Tech FGPMMOPA6H GPS 10Hz 1PPS

December 9, 2017

FGPMMOPA6H GPS manual

• 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)
• Power supply: 3.3 V, 25 mA
• NMEA: GGA, GSA, GSV, RMC, VTG over 2.8 V TTL (p. 17)

The PA6H GPS module and Raspberry Pi can make 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.

NMEA over UART: the Raspberry Pi UART via PySerial can read NMEA with a program such as NMEAutils. The hardware UART connection is to GPIO pins 14 and 15 on the various Raspberry Pi versions.

Red Pitaya NMEA over UART: 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 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. This technique (with different hardware) was used for the HiST auroral tomography system.