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TinyCircuits / TinyCircuits-Tiny-Game-Engine

MicroPython game engine for TinyCircuits Thumby Color
GNU General Public License v3.0
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Hardware: white halo issue #70

Closed TinyCircuits closed 4 months ago

TinyCircuits commented 4 months ago

Sometimes when units boot up they get a white halo around the edges of the screen. The level of severity varies but sometimes washes out the entire screen.

The issue is most common when a unit has all of its files erased and then is turn off and back on after putting files back on it. Also seems to happen after loading .uf2s onto the device.

TinyCircuits commented 4 months ago

This issue can be replicated by putting the device into BOOTSEL mode or by removing the main.py file (so the screen is not initialized), leaving it sit while plugged in or on battery, and then by quickly turning the device off and back on (after putting main.py back on).

Figured out that this was an issue with the hardware where the LCD/screen reset line needed a small pull down resistor. After modifying the hardware, the replication steps above do not result in a white halo on the screen. Without the resistor, the reset line was not in the correct state when driven and the screen was being run in a invalid state, according to the controller datasheet.

Nothing can really be done software-wise to fix this issue (although occurrences could probably be minimized by sending commands as soon as possible). The next hardware revision will have the pull-down resistor.