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SeeSharp228-Jun-21 1:38
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GeneralVICTORY! (Programming for e-paper devices is *hard*) Pin
honey the codewitch25-Jun-21 11:05
mvahoney the codewitch25-Jun-21 11:05 
Standing atop a pile of code and e-paper displays, I am victorious. Veni vidi vici.


You all get to be my rubber duck. Again. This because I work alone, and don't have a coworker I can bore with this. Laugh | :laugh:

I've been writing some e-paper drivers, and after I got the mode switching out of the way, I ran into so many other issues.

The datasheets for these devices are cryptic.

The sample code provided by the manufacturers invariably bit bangs the SPI and does things like reset the device 3 times in a row and other things that aren't production-worthy, leaving me having to kind of second guess things (why are they bit banging instead of using the SPI API? What is the target MHz here? do I really need to reset 3 times in a row? will one work? twice etc)

And then there's the issue of partial vs full updates.

Full updates kind of "wash" the screen. Otherwise you get residual ink build up that leads to ghosting from previous images. They take awhile for the screen to refresh when doing it this way.

Partial updates are much much faster but do not "wash" the screen, meaning you get ink build up as you're doing it, but the updates go by quick.

*sigh*

My driver is kind of working, but it's not washing properly, and I also don't like the code. Plus sometimes I get a weird screen during the washing process - like an old tube TV picture's hsync going bad, and then that image is ghosted onto the next screen.

It's frustrating. I'm so close, but none of this is easy to run down.

These displays are *tricky*. I didn't have this complication with the ones that don't support partial updates, but supporting partial updates on the (more expensive) devices that support it is too important to punt, even if it's heckin' tricky to do.

Man, this whole e-paper endeavor has turned into quite a bear.

Real programmers use butterflies


modified 25-Jun-21 23:18pm.

GeneralRe: Programming for e-paper devices is *hard* Pin
OriginalGriff25-Jun-21 11:57
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GeneralRe: VICTORY! (Programming for e-paper devices is *hard*) Pin
obermd26-Jun-21 14:36
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GeneralRe: VICTORY! (Programming for e-paper devices is *hard*) Pin
honey the codewitch26-Jun-21 14:59
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GeneralRandom generator Pin
Henco Du Plessis25-Jun-21 8:05
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