Working with TIVAC

The campus rover 4 prototype is based off of the "chefbot" from the textbook "Learning Robotics Using Python" by Lentin Joseph. Rather than using an OpenCR board like a turtlebot3, it uses a Tiva C Launchpad. To write code for the Tiva C, we need two things:

1. The Energia IDE to write our code, compile it and upload it to the board.

2. rosserial_tivac to allow the Tiva C to act like a ROS node.

Step 1. Download the Energia IDE

go to The Energia Download Page to get the IDE. Then, choose where to extract the files. You can put them wherever you like, I chose to keep them in my Downlaods folder, so for me the path to the IDE and it's related files/ folders is ~/Downloads/energia-1.8.10E23-linux64/energia-1.8.10E23, because my version of energia is 1.8.10E23. In the future, your version may be different.

To make it easy to open the Energia IDE, I added this alias to my .bashrc:

alias energiaIDE='cd ~/Downloads/energia-1.8.10E23-linux64/energia-1.8.10E23 && ./energia'

Step 2: Download and install rosserial_tivac

We need to download, build and install the rosserial_tivac package.

Run these five commands in your terminal:

cd ~/catkin_ws/src
git clone https://github.com/vmatos/rosserial_tivac.git
cd ~/catkin_ws
catkin_make
catkin_make install

Add this line to your .bashrc (preferably near similar lines that were automatically added when ROS was installed):

source ~/catkin_ws/install/setup.bash

Step 3: Enable energia to complie with ROS

In the terminal, cd to where energia is. So, because my Energia is in the Downloads directory, I input:

cd ~/Downloads/energia-1.8.10E23-linux64/energia-1.8.10E23

ls to see the files and subdirectories in the folder. There should be a libraries directory. Run this command:

rosrun rosserial_tivac make_libraries_energia libraries/

If that command completes without error, you should find the directory ros_lib inside libraries. Congratulations! You can now turn your Tiva C launchpad into a ROS node.

This guide up to this point was adapted from here

Step 4: Configure Energia for Tiva C

Open Energia. From the Menu at the top, Select Tools, then Boards, then Boards Manager.

In the Boards Manager, scroll down and select Energia TivaC boards, and install it.

Under Tools/Boards again, select LaunchPad (Tiva C) tm4c123 (80MHz)

Now, plug the Tiva C into your PC via USB. Now, under Tools you should now be able to select Ports, and the only option should be /dev/ttyACM0. Select it.

You are now configured to compile and upload your code to the Tiva C board by using the Upload button (it looks like an arrow pointing to the right)

Step 5: enabling your computer to send data to the TivaC

1. Download the Ti udev rules

2. in a terminal, cd to where you downloaded the udev rules. then, move them using this command: sudo mv 71-ti-permissions.rules /etc/udev/rules.d/

3. restart the udev service using this command: sudo service udev restart

PRO TIP: Follow the same three steps above on the robot's raspberry pi to give rosserial access to communicate with the tivac. (a restart may be required)

Step 6: running the node and communicating with ROS

For the node on your Tiva C to communicate with ROS, the computer it is attached to must be running the serial_node from the rosserial_python package. This node is installed by default along with ROS. Run it independantly with rosrun, or add it to your project's launch file.