Why are eink displays so annoying to work with?
The generally write only nature of the interface is definitely part of it. No way to read back any config or status registers to see what's happening. You either get an image or not.
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@jpm this is a reset line, a mode strap, and half duplex SPI.
I'm able to read what looks like valid config data out of the OTP but when I send a refresh command with all black image I don't see anything. Some of the display perimeter and some segments out by the controller flash a bit so it's alive and powered but doesn't seem happy
@azonenberg yep I feel this. Could be a magic wakeup sequence not followed exactly, could be slightly bad timing, could be a faulty display
@jpm it's not a bad display i have a whole batch of them and have used one on another board fine using almost the same code.
I'm suspecting subtle timing or bugs related to half duplex on the stm32h7 spi which I haven't done before. I saw some timing weirdness i still need to investigate
@azonenberg oh yeah, display controllers are so so bad. I’m looking at one that’s got a SPI-shaped-if-you-squint interface that is technically read-write but uses a single data line…