Continuing the discussion from I have a sick robot. .:
@cleoqc
Working on Charlie, I noticed a significant functional difference between Charlie and Charlene:
The Waveshare 2.13" e-paper displays V1 and V2 work on both Charlie and Charlene. Likewise the 2.7" e-paper Hat works on both robots.
However, the 2.13" e-paper display DOES NOT WORK on Charlie, but DOES work on Charlene.
Since I’ve been having connection problems with Charlie’s interface connector, I decided the time had come to replace it.
The result was a butcher-job of epic proportions.
I had to drill a 3mm hole to pass the rework wiring through, and my money’s on other connections failing later on.
The result:
No change. The V3 display still wouldn’t work on Charlie, but would on Charlene.& so I examined the boards more carefully.
Charlie’s board, (with the 26 pin connector is version 3.2.2, corresponding to the latest schematic on.the GoPiGo repo on GitHub.
Charlene’s board, (with the 40 pin connector), is version 3.3.0, and there is no corresponding schematic on GitHub.
Note the following significant difference:
(3.2.2 revision GoPiGo3 board)
(3.3.0 revision GoPiGo3 board)
If you look up at the top center of the board, (just under the connector) you will notice an IC and two transistors on the 3.2 version board, and on the 3.3 version board the IC has been entirely replaced by transistors and diode-resistor isolation networks.
This represents a significant circuit change, and there may be other changes elsewhere that I haven’t noticed yet. This may also account for functional differences that I had attributed to connector issues.
I have to confess to being a bit peeved since I spent the lion’s share of yesterday trying to replace a connector that probably didn’t need replacing.
I have created an issue against the GoPiGo GitHub repository asking for updated schematics.
Be aware of these differences and note that certain items built later than the 3.3 version board may not work with earlier versions of the GoPiGo.