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epd1in54b (V1) dim red color and border around screen on RasPi 4B #257

Open ShadF0x opened 2 years ago

ShadF0x commented 2 years ago

Tried running RasPi epd1in54b demo for V1 display.

Red color is very dim, almost invisible. If I draw the same framebuffer as both red and black the picture gets better, but it's still nowhere near as vivid as I saw in other people's projects.

Also, the demo causes a thin black border to appear around the edge of the panel.

Documentation on the panel says that both the contrast and the border can be controlled via either VCOM or "Border Waveform Control register", but I can't find any info on how to actually do it.

cjs30 commented 2 years ago

Have you found how to do this yet? I will have a play this morning.

ShadF0x commented 2 years ago

Nope.

After reading the specs some more, I've found something that mentions Border Waveform Control on page 25.

Seems like the doc references to this: https://github.com/waveshare/e-Paper/blob/dee10ea85d16df3e8879c31ad4f16d1925551307/RaspberryPi_JetsonNano/python/lib/waveshare_epd/epd1in54b_V2.py#L111

In theory, if you change 0x3C to something else (say, to 0x38 or 0x3F), it should affect the red channel.

That said, I didn't have time to test it yet, and I have no idea what most of the abbreviations they use mean (even after googling), so I might be dead wrong.

w3p706 commented 1 year ago

I was able to change the border of my display to black with

_writeCommand(0x3C); // BorderWavefrom
_writeData(0x00);

instead of the orginal which gave a white border

_writeCommand(0x3C); // BorderWavefrom
_writeData(0x05);

but i didn't found a description of the values for this command.