This is a simple "Hello World" test program which demonstrates hardware control over BeagleBoard Black using C# and Mono to blink the four USER LEDs.
- BeagleBoard Black
- Angstorm, or Ubuntu (Installing Ubuntu On BeagleBone Black)
- Mono
I baked this in Visual Studio under Windows, and used WinSCP to copy the code over to the BeagleBoard using SSH, whilst USB tethered.
Installing Mono is straight forward with apt. I tend to install mono-gmcs mono-mcs mono-xsp4 mono-xsp4-base mono-devel mono-xsp4 mono-csharp-shell. XSP makes a handy ASP.NET webserver.
$ sudo apt-get install mono-gmcs mono-mcs mono-xsp4 mono-xsp4-base mono-devel mono-xsp4 mono-csharp-shell
The installation can be much slimer, of course.
The only code you really need to run the demonstration is Program.cs, so the easiest option might be wget:
$ cd /tmp
$ wget https://github.com/pingfu/beagleboard-led-chaser/blob/master/Chaser/Chaser/Program.cs
$ dmcs Program.cs
$ sudo ./Program.exe
That's it.
This program is a simple wrapper to the following bash commands. Manipulating the BeagleBoard hardware is as simple as writing data to a file.
echo default-on > /sys/class/leds/beaglebone:green:usr0/trigger
echo default-on > /sys/class/leds/beaglebone:green:usr1/trigger
echo default-on > /sys/class/leds/beaglebone:green:usr2/trigger
echo default-on > /sys/class/leds/beaglebone:green:usr3/trigger
Set the LEDs back to their default configuration
echo heartbeat > /sys/class/leds/beaglebone:green:usr0/trigger
echo mmc0 > /sys/class/leds/beaglebone:green:usr1/trigger
echo cpu0 > /sys/class/leds/beaglebone:green:usr2/trigger
echo mmc1 > /sys/class/leds/beaglebone:green:usr3/trigger
We flashed our BeagleBoard with a specially prepared image of Ubuntu made by Robert C Nelson. The version I used in December 2013 was BBB-eMMC-flasher-ubuntu-13.04-2013-10-08.img.xz from http://rcn-ee.net/deb/flasher/raring/. The same paths ought to work for Angstrom too, we just find mono easier on Ubuntu thanks to apt.
More information about directly working with files to control the hardware here
If you're planning to do any serious work with C# and the BeagleBoard, it's worth knowing about Ahead-of-time compliation. There is more information about that on the Mono project's website.
Cheers http://markable.in/editor/. Also check out The making of BeagleBone Black and the BeagleBone GamingCape