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Connecting Tic T 834 with Raspberry Pi 4


I am working on connecting Raspberry 4 with the Tic motor controller following the instruction Pololu - 12.8. Example I²C code for Linux in C (section 12.8). However, after adding dtoverlay=i2c-gpio into the /boot/config.txt file as described in the instruction and after rebooting I do not see the /dev/i2c-3 has been created. I am not sure what causing this issue. Any help in resolving this probelm will be appreciated.

Thank you.


It looks like you might have made a typo in your post, but just in case and for the people following this discussion, dtoverlay=i2c-gpio should be added to /boot/config.txt, not /dev/config.txt.

Can you reboot your Raspberry Pi and run cat /boot/config.txt then ls /dev/i2c* and post the results here?

- Amanda

Hi Amanda,

Thank you for your reply. I have fixed the typo in the post. I actually added dtoverlay=i2c-gpio to /boot/config.txt but made typo in the post. I still do not see /dev/i2c-3 has been created. By doing

$ ls /dev | grep i2c

I see the following files


Further, I am using Ubuntu 21.04 on Raspberry Pi 4.


Our instructions were written for Raspbian, and apparently Ubuntu works a little differently. We tried it out and found that you shouldn’t need to add that line to config.txt (which is in /boot/firmware for Ubuntu). The Tic should be on the i2c-1 bus, so you should use i2c-1 instead of i2c-3 on line 108 in the example code. Let us know if that fixes the problem for you.

- Amanda

Hi Amanda,

Thank you for the clarification. I am actually interested in using Python script. In that case, In that case I need to change the bus value to 1 instead of 3 at line number 55, right?


I can connect to the Tic board using Raspberry Pi 4 now. Thank you for the help.

Yes, you would need to change the bus number from 3 to 1 on line 55 in the example I2C code for Linux in Python, which it sounds like you did. Glad your setup is working now! Please let us know if you have any additional questions.

- Amanda