This 2-in-1 PR started with the goal of support the Bangle.js 2
smartwatch with *no USB*.
* Adds "secure" DFU build support with a committed private key.
* Adds 3-bit color support with one dummy bit for the JDI memory display
* Allows nrf boards to have a board_background_task() run in RUN_BACKGROUND_TASK.
This is needed because the Bangle.js 2 uses the watchdog to reset.
* Renamed port_background_task() to port_background_tick() to indicate it
runs on tick, not RUN_BACKGROUND_TASK.
* Marks serial connected when the display terminal is inited. This means
that safe mode messages show up on the display.
ACep, 7-color epaper displays also pack 3 bits in 4. So, I added that
support as well.
* Adds 3-bit ACeP color support for 7-color e-paper displays. (Not
watch related but similar due to color depth.)
* Allows a refresh sequence instead of a single int command. The 7" ACeP
display requires a data byte for refresh.
* Adds optional delay after resetting the display. The ACeP displays
need this. (Probably to load LUTs from flash.)
* Adds a cleaning phase for ACeP displays before the real refresh.
For both:
* Add dither support to Palette.
* Palette no longer converts colors when set. Instead, it caches
converted colors at each index.
* ColorConverter now caches the last converted color. It should make
conversions faster for repeated colors (not dithering.)
* write any partial message
* instead of "..." show a sensible (translatable) message
This does slightly lower the amount of data that can be printed,
and makes the exact amount dependent on the language. However, if boot.py
intentionally needs to produce larger amounts of output, it can
deliberately mount the filesystem in RW mode and perform any writes needed.
In that case it's up to the boot.py to choose an appropriate way to
limit the number of writes if needed for the application.
These changes result in working neopixel functionality. I've tested on
both the zero2w and the pi4b (The 4b didn't exhibit the original issue)
and the boards now behave properly with 1 to 30 pixels and the board hanging
no longer occurs.
Remove mod that didn't help during testing
Restoring back to original structure
Replace 2 microsecond delay w/deterministic loop
Remove unneded check for empty queue
Put transmit delay outside loop so Queue is used
Make sure last transmission is complete
If an exception's chain or context can refer to a pointer from a different
VM, a crash would typically result.
This couldn't turn up on UNIX testing because the VM is never torn
down and rebuilt like it is on hardware.
Because in the 'static' case the GeneratorObject is now fully initialized
whenever it's raised, the initialization can be dropped, which reduces
the flash size slightly.
Closes: #7565
