PixRacer Serial Mapping

Many different names are given to the serial hardware on PixRacer where ArduPilot is concerned. This document attempts to supply a mapping between them.

DataSheet Param Prefix HW Label Default Protocol Notes
  SERIAL0 USB Console Micro-USB Plug
USART2 SERIAL1 TELEM1 MAVLink bootloader serial##
USART3 SERIAL2 TELEM2 MAVLink  
UART4 SERIAL3 GPS GPS  
USART8 SERIAL4 FRSky GPS2** normally inverted
USART1 SERIAL5 ESP-01 MAVLink  
UART7 SERIAL6 DEBUG disabled  

Notes:

** While the default here is GPS, the port is inverted so this won’t work with a GPS, it was intended for use with FrSky receivers for telemetry. Usually SERIAL4_PROTOCOL should be set to an FrSky protocol and a diode tied from TX (anode) to RX and attached to the SPort of an FrSky receiver.Alternatively, SERIAL4_OPTIONS can be set to 2, to disable the inverters for normal use.

## can be used for firmware upload instead of USB port, if needed.