OLED Display Using SPI Interface Scrambled


#1

Hello,

I’m adding an Adafruit ssd1325 OLED 2.7" display to my GOPIGO3 using the SPI interface on CE0. From your schematic it appears the GOPIGO3 board uses CE1. Even with the GOPIGO3 hat removed I am getting a scrambled display. When I move the breakout rig to another PI 3B (non-Raspbians for Robots), the display works fine after resetting it. Both PI’s are running up-to-date Stretch. Do you know if Raspbian for Robots does anything to the SPI interface that might cause a problem or have any other thoughts on what might be going on.

Many thanks!
John


#2

Hi @mindware01,

I confirm that the GoPiGo3 uses CE1. I’m not sure yet what’s causing it, but I know there are some pins that get configured when Raspbian For Robots is created.

We can start ruling them out one by one. Since you’re focused on the GoPiGo3, use a pure Raspbian distribution and run the following command to setup the GoPiGo3:

curl -kL dexterindustries.com/update_gopigo3 | bash -s -- --bypass-gui-installation

The above command skips the GUI installation as that takes a bit of time to install it.

If you see the LCD working after this step, then that’s great and if you want, you can go further an add other installations until it breaks (and just so you know, the GUI should only be installed once as it’s not necessary to do it again for all the number of installations there are).

The other installations are:

curl -kL dexterindustries.com/update_sensors | bash
curl -kL dexterindustries.com/update_brickpi3 | bash
curl -kL dexterindustries.com/update_gopigo | bash
curl -kL dexterindustries.com/update_pivotpi | bash
curl -kL dexterindustries.com/update_sensors | bash
curl -kL dexterindustries.com/update_grovepi | bash

Let me know how it goes for you.

Thank you!


#3

Thanks for the troubleshooting steps! I found that a clean install of Stretch had the same problem. So, I debugged the luma.oled code and added a fix with a line of code. It’s strange though that I didn’t have the problem on my other Stretch/luma.oled install. Anyway it’s working much better with Raspbian For Robots. I still have clear up some GPIO pin conflicts which luma.oled has documentation for. Many thanks for your help. The install steps you noted would be great for troubleshooting any Raspbian For Robots issues.