e-paper
2 posts tagged e-paper · all posts
Debugging
I Debugged a Display by Photographing It
by Robert Jefe Lindstaedt Aug 20, 2026
Orientation bugs on a 22 mm e-paper panel, one build-flash-photograph cycle at a time. Symmetric test patterns hide flips, the controller's own 180-degree mode mirrors at byte granularity, and partial refresh has prerequisites nobody documents.
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Debugging
The HAL Said Ok. The Pin Never Moved.
by Robert Jefe Lindstaedt Aug 20, 2026
Two days blaming a booster circuit, two e-paper panels and an adapter board. The actual bug: esp-idf-hal returns Ok() for GPIO writes that never reach the pad, because the pin belongs to the JTAG block.
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