Getting Started Part 1: Serial Connection

This blog post will hopefully address some common starting questions to those who are new to embedded systems. Things like connecting connectors, setting up serial console (Linux & Windows), and writing sdcard images (Linux & Windows). If you feel we're missing anything, feel free to comment below and we can expand this blog post, hopefully keeping this as the go-to source for getting started on our boards.

Serial Console

Shipped with all our boards is a console cable, and on all our boards is a header labeled "SERIAL". The header is labeled J17 on all boards. You can see the cable and where it attaches here for the Nitrogen6x:

 

You'll need to attach the DB9 connector labeled "CONSOLE" to a serial port, or more likely a usb-to-serial converter. Here are pictures of my usb-to-serial converter, just attach the USB cable to your computer and you're good to go:

When you attach the usb-to-serial converter on Linux, you should be able to see mounting information by grepping dmesg, like "dmesg | grep ttyUSB", as you can see here you'll notice it mounts on /dev/ttyUSB0:

ubuntu@boundary:~$ dmesg | grep ttyUSB

[ 26.145040] usb 1-6.4: Keyspan 1 port adapter converter now attached to ttyUSB0

On Windows, you'll be able to see the device under Device manager.

 

Our default serial speed rate is 115200 on all our boards, so you'll need that information to properly configure your console application. There are a great number of console applications you can use on both Linux and Windows. Two popular Linux console applications are "screen" and "minicom". Personally, I use screen and will give examples for it here, although like many things it comes down to personal preference and how well you know the keyboard shortcuts and configurations.

The screen command is simple, "sudo screen /dev/ttyUSB0 115200" tells the application to open the serial port on /dev/ttyUSB0 and run at the speed 115200bps with admin permissions:

ubuntu@boundary:~$ sudo screen /dev/ttyUSB0 115200

Now if you power the board you'll see the console start with u-boot:

A popular Windows serial console application is PuTTY, you can download it here. You'll need to configure the serial port under Device Manager and set the baud rate to 115200 as you can see here:

 

Then you'll need to open PuTTY and select the serial radio button and enter the COM# shown in Device Manager as well as setting the baud rate to 115200 and open the console

Then if you power up your board you should be U-Boot start to load