The ublox neo 6m GPS receiver

The Neo 6M GPS receiver

Most GPS receivers use a UART to communicate with their hosts and the Neo 6M is no exception. The ESP32 has 3 hardware UARTs with the following default connections:

UART number	default Rx, Tx, GPIO pins
0	3,1
:--	:--:
1	9,10
:--	:--:
2	16,17
On our system UART 0 is reserved for REPL, GPIO 9 and 10 are not pulled out to the connector and GPIO 16,17 are used by PSRAM. Fortunately the ESP32 allows to re-map UARTs to just about any GPIO pin using the GPIO matrix and the MicroPython driver supports the re-mapping. We can define a UART as follows:
uart2=machine.UART(2, baudrate=9600, rx=21, tx=22, timeout=10000)
For more information about the ESP32 UART driver in MicroPython see
https://docs.micropython.org/en/latest/library/machine.UART.html#machine-uart
The card on which the Neo 6M GPS receiver is mounted has 4 connection pins (starting from the left):