Can't get my Waveshare e-paper display to update without creating a new project

Good morning everyone,

I’m working with a 7.5" Waveshare e-paper display (B&W), I already succesfully completed some projects on it thanks to the GxEPD 2 libraries, but on the last project which I’m working on, I’m experiencing some problems with the display.

I’m currently basing my code on one of the library examples to retrieve via HTTP an image to display, but oddly enough, I can get the e-paper to display the image successfully only by creating a new project everytime I need to make a change. That means that if I flashed again the very same code (which worked the first time), the console outputs correctly but the display won’t update. This problem is often (and not even always) fixed by creating a new project, copy-pasting the same exact code into it, making the change and flashing again. This workaround doesn’t always work everytime, and I’m quite confused. Maybe my code is missing a function to reset some internal parameters or components, but basically I flashed the board like 40 times today and only 4 times the display updated / responded at all, while the console seemed to work just fine.

The 2 images I tried to display are in the right format since I was able to display them correctly at least once on the epaper.

I also tried to unplug and plug the board again to the usb port, and also I already tried toying with the BOOT and EN buttons, but the display won’t update/respond at all.

I’m attaching the code I’m flashing (not so well-optimized for my case at the moment, but it worked once).

I hope someone can help me with this. Many thanks.

display_image.zip (4.22 KB)

@tHe_giafra_sHoW,

This was already your 10th post, so you should know you need to provide enough information!

What processor and processor board do you use, and what connection module?

Maybe you use an e-paper HAT from Waveshare, with a 3.3V processor. There is a known issue with marginal supply voltage especially for the 7.5" e-papers caused by the LDO on the HAT.

Ok, I see that you use a Waveshare e-Paper ESP32 Driver Board. This should be ok with supply voltage to the e-paper and the on board driver voltage generation circuit.
But marginal supply might still be an issue; try to connect the processor to a USB3 connector instead of USB2, to check if this helps.

@ZinggJM

You're right, I should have provided more infos regarding the specs.

Yes, you got it right, I'm using a 7.5" waveshare e-paper esp32 driver board.

I checked the USB ports of my notebook, the board is connected to a SS port.

I can add some more details, after some tries today I figured out that the problem might not be related to the code or the project. I tried unplugging all the parts and connections and plugging them in again and the display started to work for a bit. Then it stopped. I was able to test the code I attached above and also the main project I'm working on.

This trick didn't work a second time after the display stopped working again. I also tried to change the USB cable, and the adapter, with no avail.

@tHe_giafra_sHoW,

I assume you know how the flex connector "works"; the version on the ESP32 driver board has a black lever that needs be gently pulled up, then the flex cable moved in, and then the lever pushed down to fix the cable and make contact. And you surely have set the RESE switch to the correct position for the e-paper panel, position B for 0.47ohm.