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Debug UART

The debug UART is a three-pin, 2.54 mm header that carries the serial console. It is on the top side of the board, near the corner next to the POWER USB-C port. Pin 1, RXD, is marked with a triangle on the board.

Top view of the Edge 2 board with the debug UART header marked near the lower left corner, and a close-up of its three pins: 1 RXD, 2 TXD, 3 GND

Figure 1. The debug UART header

Specifications​

  • Three pins: RXD, TXD, GND
  • 3.3 V logic
  • The bootloader and Mixtile OS use it at 1500000 baud, 8N1, no flow control

Pin Assignments​

Pin#PinNamePinTypeInput/OutputSignal Description
1UART2_RXDsignalInputUART2 receive data, for debug
2UART2_TXDsignalOutputUART2 transmit data, for debug
3GNDPowerNAPower and signal reference ground

Wiring​

Connect a USB to TTL converter's GND to pin 3, its TXD to RXD (pin 1), and its RXD to TXD (pin 2). Do not connect the converter's VCC.

Wiring between a USB to TTL converter and the Edge 2 debug UART: GND to GND, TXD to RXD, RXD to TXD, VCC not connected

Figure 2. Converter wiring

For the complete serial-console connection procedure, see Connect to Edge 2.