Working with serial

It is important to have a USB-UART adapter and work with serial if you want to play with Domino. With serial, you will be able to access the console and have full control of the OpenWrt system and bootloader.

USB-UART adapter

Domino Pi has a built-in USB-UART bridge. So you have two serial connectors, one is on the MicroUSB power connector and the other is on the Ethernet board, which is connected to the Domino Core.

USB-UART

Just connect Domino Pi to your computer. It will be powered up and at the same time you will have access to the serial.

Sometime you need to connect directly to the Domino Core UART, and you will need a USB-UART adapter.

ATTENTION: If you are connecting with an external USB-UART adapter, be sure connect to the correct pins:

Serial Connections

In Windows

If you want to use connector 1, Windows will automatically detect the USB to UART Bridge and install drivers.

USB-UART

Find its com number. (Which is COM36 in my case.)

If you use your own USB UART adapter, you will have a com number also. (Which is COM4 in my case.)

You need a serial term, we recommend PuTTY and RealTerm. Download them for free.

Launch PuTTY and input COM36 as the "Serial line", 115200 as speed, check the Connection type as Serial, then click Open.

USB-UART

Then press Enter you will enter OpenWrt.

USB-UART

You can also connect to COM4 using the same way.

USB-UART

At the same time, you can also connect to the serial using Connector 2. Execute realterm, fill the currect Baudrate 115200, port number 36 and click Open.

USB-UART

ATTENTION Only one term can connect to one serial device at the same time.

Working with two serials

In the above instructions, we used two terms connected to two serial ports: PuTTY connecting to Connector 2 (original uart of Domino Core) and RealTerm connecting to Connector 1 (the build in USB-UART bridge). Once you connect RealTerm, you will find that in PuTTY you cannot input anything, but you can input from RealTerm.

USB-UART

You can enable input in PuTTY by clearing RTS in RealTerm. Go to the "Pins" page and click "Clear" in RTS section. Now you will be able to input in PuTTY, but not in RealTerm. To enable input in RealTerm again, click "Set" in RTS section.

In Linux (Ubuntu)

We only test in Ubuntu. For any other distro, if you have any questions, pls discuss in the community.

In Ubuntu, when connecting Domino Pi to your computer's USB directly, it will be identified as /dev/ttyUSB*, e.g. /dev/ttyUSB0 if you only have USB serial device.

ckermit

Download ckermit from http://www.columbia.edu/~kermit/ckermit.html#download or use sudo apt-get install ckermit to install it.

$ sudo apt-get install ckermit

make a file with name .kermrc in your home directory. The content is as following:

#cat ~/.kermrc

set line /dev/ttyUSB0
set speed 115200
set carrier-watch off
set handshake none
set flow-control none
robust
set file type bin
set file name lit
set rec pack 1000
set send pack 1000
set window 5

Now execute kermit sudo kermit -c to get access to the console of your Domino Pi.

sudo kermit -c

If you have multiple serial devices, create one configure file for each device, and then put the file name as parameters. For example, for ttyUSB1, use sudo kermit ~/.kermrc_ttyUSB1 -c.

sudo kermit ~/.kermrc_ttyUSB1 -c

The escape key for kermit is Ctrl+\ followed by c.

Other tools

You can also use screen or cu to access the serial.