Getting Started with MATLAB Support Package for BeagleBone Black Hardware

Introduction

The MATLAB Support Package for BeagleBone Black Hardware enables you to communicate with BeagleBone Black hardware remotely from a computer running MATLAB. The support package includes a MATLAB command line interface for accessing BeagleBone Black hardware's I/O peripherals and communication interfaces. Using this command line interface, you can collect data from sensors connected to BeagleBone Black hardware and actuate devices attached to BeagleBone Black hardware.

In this example you learn how to create a beaglebone object to connect to BeagleBone Black hardware from within MATLAB. You examine the properties and methods of this object to learn about the status of basic peripherals such as digital I/O pins (also known as GPIO), SPI, I2C, and Serial. Using this object, you execute shell commands on your BeagleBone Black hardware and manipulate files on the BeagleBone Black hardware.

Prerequisites

Required Hardware

To run this example you need the following hardware:

Create a beaglebone Object

Create a beaglebone object.

bbb = beaglebone();

The bbb is a handle to a beaglebone object. While creating the bbb object, the MATLAB connects to a server running on the BeagleBone Black hardware through TCP/IP. If you have any issues with creating a beaglebone object, see the troubleshooting guide to diagnose connection issues.

The properties of the beaglebone object show information about your BeagleBone Black hardware and the status of some of the hardware peripherals available. The numeric IP address or the hostname of your BeagleBone Black hardware is displayed in the DeviceAddress property. The beaglebone object detects the model and version number of your board and displays it in the BoardName property. The GPIO pinouts and available peripherals change with the model and version of your BeagleBone Black hardware.

Turn an LED on and off

There are user LEDs on BeagleBone Black hardware that you can turn on and off. Execute the following commands at the MATLAB prompt to turn the LED off and then turn it on again.

led = bbb.AvailableLEDs{1};
writeLED(bbb, led, 0);
writeLED(bbb, led, 1);

While executing the preceding commands, visually confirm that the LED on the BeagleBone Black hardware is turned off and then turned on. If you are unsure where the user LED is located, execute the following command. If you are unsure where the user LED is located, execute the following command.

showLEDs(bbb);

You can make the LED blink in a loop with a period of 1 second.

for i = 1:10
    writeLED(bbb, led, 0);
    pause(0.5);
    writeLED(bbb, led, 1);
    pause(0.5);
end

Execute System Commands

The beaglebone object has a number of methods that allow you to execute system commands on BeagleBone Black hardware from within MATLAB. You can accomplish quite a lot by executing system commands on your BeagleBone Black hardware.

system(bbb, 'ls -al /home')

This statement executes a Linux directory listing command and returns the resulting text output at the MATLAB command prompt.

Perform the LED exercise this time using system commands.

system(bbb, 'echo 1 > /sys/class/leds/beaglebone:green:usr3/brightness');
system(bbb, 'echo 0 > /sys/class/leds/beaglebone:green:usr3/brightness');

You cannot execute interactive system commands using the system() method. To execute interactive commands on the BeagleBone Black hardware, you must open a terminal session.

openShell(bbb)

This command opens a PuTTY terminal. Log in with your user name and password. The default user name is 'root' and no password is required. After logging in, you can execute interactive shell commands like 'top'.

Manipulate Files

The beaglebone object provides the basic file manipulation capabilities. To transfer a file on BeagleBone Black hardware to your host computer you use the getFile() method.

getFile(bbb, '/boot/uboot/Docs/images/beagle.png');

You can then open the file 'beagle.png' containing an image in MATLAB:

img = imread('beagle.png');
image(img);

The getFile() method takes an optional second argument that allows you to define the file destination. To transfer a file on your host computer to BeagleBone Black hardware, you use putFile() method.

putFile(bbb, 'beagle.png', '/tmp');

Make sure that file is copied.

system(bbb, 'ls -l /tmp/beagle.png')

You can delete files on your BeagleBone Black hardware using the deleteFile() command.

deleteFile(bbb, '/tmp/beagle.png');

Make sure that file is deleted.

system(bbb, 'ls -l /tmp/beagle.png')

The preceding command should result in an error indicating that the file cannot be found.

Summary

This example introduced the workflow for using the MATLAB Support Package for BeagleBone Black Hardware. Using the BeagleBone Black support package, you turned the user LED on and off, executed system commands and manipulated files on BeagleBone Black hardware.