I’m working on a project with a Display HAT Mini connected to my Raspberry Pi 5. The display is connected via a 40-pin ribbon cable to the GPIO. In addition, I have a Waveshare relay HAT between the Pi and the display (see photo).
When the Pi is powered on, the display LED glows a solid bright green, and there is no backlight. I’ve had success getting the display to work properly when connected directly to the GPIO connector on the board. I’m only seeing this behavior when using the ribbon cable. The cable is from AdaFruit and is standard, 40-pin straight thru.
What I’ve tested and tried:
I’ve tried connecting directly to the Pi board and removing the Waveshare relay board. Same result either way.
I’m not using RPi.GPIO, but rather, GPIOZero. The Pi is running the Bookworm port.
I’ve tried a different Display HAT mini, and it behaves the same way.
I’ve tried connecting to a Pi 4 device, and have the same behavior.
I checked to make sure pin 1 is aligned correctly on both ends of the cable.
I confirmed SPI is enabled with raspi-config.
Any thoughts or ideas as to what I can be missing? Thanks in advance!
Just to recap, it only happens when using the ribbon cable?
The schematic shows what pin is for the green led signal, I’d check that pin for a ground signal. It should be floating / no ground for the LED to be off.
Yes, it only happens with the cable. I can check the pin, but wouldn’t I see the same issue when the display is connected directly to the GPIO port? Could it be a cable issue? Can anyone suggest a 40-pin cable that will work with a TFT display?
“The display LED glows a solid bright green, and there is no backlight” only happening when you use the cable makes me think its the cable.
Is that cable a “male to female” type?
It’s female on both ends, and I was using a converter on one side.
Perhaps that’s the issue. Is there another cable you can recommend, or will any 40-pin male to female work?
Ah, yes thats your issue. I think you’ll find pin 1 on the Pi is actually going to pin 2 on the hat. And pin 2 to 1 etc. The cable you want is this one.
