Waveshare 7.5in E-ink screen not working with ESP32

[purerandom]

Hi, I recently bought a Waveshare 7.5in V2 E-ink display with raspberry pi hat (v2.3) and I cannot get it to work with an esp32 ( I believe its a Nodemcu one but it's unlabeled so IDK)
I have tried multiple different wiring configs and multiple different example sketches as well as trying esphome, the error message I received from esphome is "[waveshare_epaper:167]: Timeout while displaying image!" Also can ribbon cables be plugged in either orientation, or is it a single set direction?

That red cable is the PWR cable and none of the sketches or guides use it so it is left unplugged on purpose.

[toddnz]

@purerandom

That red cable is the PWR cable and none of the sketches or guides use it so it is left unplugged on purpose.

There is a mistake in the table on the waveshare site. I suspect they want you to connect it to D6.

The schematic shows that PWR should be connected to 3.3V, to switch the display on.

This is also mentioned briefly on the wiki, but not very clearly:

If you want to upgrade the version, you can choose one of the following ways:

• Update the program to the newest one (Arduino program only supports 7.5inch e-Paper, 7.5inch e-Paper (B), 5.83inch e-Paper, 5.83inch e-Paper (B), 2.9inch e-Paper (D), 2.13inch e-Paper (D)).
• Connect PWR pin to 3.3V.
• The empty pad on the back side is soldered with a 47K (or similar) resistor.

[purerandom]

Ok so do I plug pin into 3vots or into d6?

[toddnz]

Without checking, I imagine the waveshare example code will change D6 between 3.3V and ground, as a power-saving technique.

I don't believe you will have any issues from simply connecting PWR directly to 3.3V. The display will remain connected to power.

[ksteczk]

@purerandom - is that working for you? I have similar situation but my ESP32 has only one 3.3V pin, probably like yours. What pins exactly did you use to make it working? I took this connection scheme:

BUSY->GPIO4|D4
RST->GPIO16|RX2
DC->GPIO 17|TX2
CS->GPIO5 (SS)|D5
CLK->GPIO18 (SCK)|D18
DIN->GPIO23 (MOSI)|D23
GND->GND|GND
VCC->3.3V|3V3

and only PWR remains unplugged and screen blank.

[purerandom]

So it turns out that the PWR pin does need to be connected to power/3.3v for it to work, so try powering the PWR pin and see what happens, that is what fixed it for me.

[mswsn]

What did you do with the VCC pin?

[ksteczk]

I connected the PWR pin to 3.3V so that now I have both 3v3 and PWR connected to one 3.3V pin since the board has only one 3.3V pin.
VCC remains unused for now as I'm powering the board from USB port.