Board communication

There are two ways to communicate with the board in default mode: ssh over a network connection (Ethernet or WiFi) or serial.

UART debug connection

This method does not require to have a working OS on the board, it's thus useful to debug things that may prevent one to correctly boot.

Check the pins to connect in the board description.

Important

The board logic level is 1.8V. Set the FT232RL converter accordingly.

Once it's done, power the board. You should see a new device appear in your /dev directory, such as /dev/ttyUSB0. If you are using a virtual machine, you might need to forward the USB device to the VM.

We can now connect to that device, for example using picocom (you might need to install it first). We can establish a serial connection with the board like so:

$ picocom -b 115200 /dev/ttyUSB0

Send and receive files

Install missing package

To exchange files with the board over the UART connection, we need to install an extra package lrzsz. You can establish an Internet connection through WiFi using nmcli. List the available AP:

$ nmcli d wifi list

To connect to a regular WPA2 network called SSID, the following command is enough:

nmcli --ask dev wifi connect SSID

For an enterprise network such as eduroam, use this configuration, replacing USERNAME and PASSWORD:

$ sudo nmcli con add type wifi ifname wlan0 con-name eduroam ssid eduroam
$ sudo nmcli con edit id eduroam
nmcli> set ipv4.method auto
nmcli> set 802-1x.eap peap
nmcli> set 802-1x.phase2-auth mschapv2
nmcli> set 802-1x.identity USERNAME
nmcli> set 802-1x.password PASSWORD
nmcli> set wifi-sec.key-mgmt wpa-eap
nmcli> save
nmcli> activate

Afterwards, install the missing package:

sudo apt update && sudo apt install lrzsz

Send a file from the board to the host

citro@board:$ sz filename

Then hit ctrl+a ctrl+r(picocom). You will see *** file:. Just press the enter key to download the file.

Send a file from the host to the board

citro@board:$ rz

Then hit ctrl+a ctrl+s(picocom). You will see *** file: in which you can type the path to the file you want to transfer to your board. You can use the tab key to auto-complete said path.

Note

You might need to have lrzsz installed on your host machine.