Connect the flight controller to the Betaflight configuration and switch to the CLI configuration interface.
resource SERIAL_TX 1 NONE | //Turn off the serial port function of the TX1 pin |
resource PINIO 1 A09 | //Configure the TX1 pin (i.e. A09 pin) as the No. 2 PINIO function |
set pinio_box = 40,255,,255,255 | //Set PINIO function range |
save | //Save configuration |