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.