ESP32 timing

A project log for EPDiy: 9.7"/6" E-Paper controller

I always wanted a large, affordable E-Ink screen to play around with. This board talks to cheap E-Reader replacement screens with an ESP32.

ValentinValentin 11/01/2019 at 11:320 Comments

Hello World! Finally, the project is ready to go public. If you have any ideas, improvements or comments to share, feel free!

During the last days, I struggled a bit with getting the timing for the gray scale output right. Each row has to be activated for a only a few microseconds to only dim it slightly. While this worked most of the time, sometimes, the code took much longer, resulting in dark horizontal stripes. Debugging this was quite a journey, since I was new to the ESP32:

Busy waiting does not seem like the most elegant solution, but it works. Refresh times are now at about 2 seconds for a gull grayscale image of 1200x825 pixels. If I could manage to already shift in new data while waiting for the current row to fade, this could be even faster. I'll have to try some things :)