Device provides a Debug UART 4 Pin 2.54mm header connection, 3V level, 1500000bps.
To connect to you will need a USB to UART converterreceiver that supports the speed of 1500000bps.
The serial port parameters are 8-N-1.
A reader using CP2102 chip did not work but FT232RL works fine:
You can use minicom or picocom to connect:
sudo minicom -b 1500000 -D /dev/ttyUSB0
sudo picocom -b 1500000 /dev/ttyUSB0
But you'll need to disable flow control with Ctrl-A x.
Here is a good overview of UART USB-to-Serial adapters:
- https://www.sjoerdlangkemper.nl/2019/03/20/usb-to-serial-uart/
- https://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT232R.pdf
Pin layout where #4 is next to USB-C port:
| Pin num. | #1 | #2 | #3 | #4 |
|---|---|---|---|---|
| Purpose | GND | V5 | TX | RX |
Remember that the TX and RX ports should be swapped between UART adapter and the board.
The V5 pin does not need to be connected if you're powering the board from another source.
See the full board diagram for more details:
You can access the recovery console by holding the Recovery button and then pressing the Power button. For this to work the device will have to be off, which requires holding the Power button long enough.