EPD feather grey out weirdness | adafruit | Page 1

pure vector Sep 17, 2022, 12:45 AM

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sooo. I found a big difference between the two units. It appears the epd screen is different which would explain why one screen always keeps contast and why one only keeps contrast during a certain power down scenario.

Screen_Shot_2022-09-16_at_2.45.34_PM.png

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Here are the osc traces of the 5v rail and 3.3v rail dropping on power disconnect. https://photos.app.goo.gl/EySFzfkYv8J2MXn36

Google Photos

4 new items by Tavis Gustafson

glad furnace Sep 17, 2022, 3:09 PM

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ohh that's fascinating.

I thought this was the same unit powered down in different ways exhibiting different behavior? But if I understand properly now, it's two different units of the same style, exhibiting different behavior from each other, but the per-unit behavior is identical to itself regardless of power-down method?

pure vector Sep 17, 2022, 11:21 PM

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At first it was the same unit powered down in different ways but then I decided to test the second unit just in case. The second unit behaves properly in all power down scenarios. Really bizarre.

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I've added two new videos to the album above. One is turning ignition off and one is pulling the plug. So it seems that dropping the voltage immediatly to 640mv is what keeps the display from greying out. I tried adding a discharge resistor across +,- but this did not work.

#EPD feather grey out weirdness