I would like to use the Raspberry Pi 3B+ to operate the rectangular HyperPixel 4.0 touchscreen from Pimoroni. However, I don’t want to plug the touchscreen directly onto the Raspberry Pi, but instead use a 3.5 meter long cable to connect the touchscreen to the Raspberry Pi.
My structure is such that I bring the Raspberry Pi to a circuit board using a 40-pin cable. From there I pick up the I²C signal so that I can connect some I/O’s on the board. There is also a 40-pin connection on the circuit board, to which I can connect my 3.5 meter cable to the HyperPixel 4.0.
When I still had the cable connection from the circuit board to the HyperPixel 4.0 with a 40 cm cable, everything worked fine. However, when I replaced the 40 cm long cable with the 3.5 m, the display only flickered, but the touch still worked. I replaced the 3.5 m cable again with the 40 cm cable and the image display on the touchscreen still didn’t work. However, if I plug the HyperPixel directly onto the Raspberry Pi header again, everything works again.
At first I thought it was the I/O board that connects the Raspberry Pi to HyperPixel, but replacing this board didn’t help either. I’m at a loss, because I don’t know where to start troubleshooting. How can I do it?