IMPORTANT for MacArthur HAT testers
Raspberry Pi 5
NMEA 1 in/out: UART2
NMEA 2 in/out: UART4
Raspberry Pi 4
NMEA 1 in/out: UART3
NMEA 2 in/out: UART5
Raspberry Pi 5
NMEA 1 in/out: UART2
NMEA 2 in/out: UART4
Raspberry Pi 4
NMEA 1 in/out: UART3
NMEA 2 in/out: UART5