UART Output

You can optionally receive the output data over a serial connection in addition to USB. The data format is the same as USB - a stream of newline separated JSON objects.

In the same way that you can send OpenXC writes over USB using the OUT direction of the USB endpoint, you can send identically formatted messages in the opposite direction on the serial device - from the host to the CAN translator. They’ll be processed in exactly the same way. These write messages are accepted via serial even if USB is connected.

chipKIT Max32

On the chipKIT, UART1A is used for OpenXC output at the 460800 baud rate. Hardware flow control (RTS/CTS) is enabled, so CTS must be pulled low by the receiving device before data will be sent.

UART1A is also used by the USB-Serial connection, so in order to flash the PIC32, the Tx/Rx lines must be disconnected. Ideally we could leave that UART interface for debugging, but there are conflicts with all other exposed UART interfaces when using flow control.

  • Pin 0 - U1ARX, connect this to the TX line of the receiver.
  • Pin 1 - U1ATX, connect this to the RX line of the receiver.
  • Pin 18 - U1ARTS, connect this to the CTS line of the receiver.
  • Pin 19 - U1ACTS, connect this to the RTS line of the receiver.

Blueboard

On the NGX Blueboard LPC1768-H, UART1 is used for OpenXC output at the 921600 baud rate. Like on the chipKIT, hardware flow control (RTS/CTS) is enabled, so CTS must be pulled low by the receiving device before data will be sent.

  • Pin 2.0 - UART1 TX, connect this to the RX line of the receiver.
  • Pin 2.1 - UART1 RX, connect this to the TX line of the receiver.
  • Pin 2.2 - UART1 CTS, connect this to the RTS line of the receiver.
  • Pin 2.7 - UART1 RTS, connect this to the CTS line of the receiver.

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