Satellite clock

A GPS module prints NMEA sentences on the UART once a second. Even before it has found its position, the $GPRMC sentence carries the UTC time.

Build: a GPS module powered from 3V3, its TX to the Pi's RXD (GPIO15) and its RX to TXD (GPIO14).

Program: open /dev/serial0 at 9600 baud, and for every $GPRMC line print its time:

UTC 09:00:03

The module has no fix during the test (it is still searching for satellites). The test's clock starts at 09:00:00 UTC.

Tip: pynmea2.parse(line) gives an object whose .timestamp is a datetime.time; strftime("%H:%M:%S") formats it.