Back when I did my Model M thingy with CircuitPython, I encountered a lot of difficulties doing I/O. For one, the I/O speed was much too slow for bit-banging anything in Python. Now, you could write some C and call it from Python, but that defeats the benefit of working with Python to begin with. Additionally, hardware peripherals seemed to be destined to be behind in Python. I doubt this will ever change, but a certain recent product seems to offer a bizarre best-of-all-worlds.
I ordered this super smol RP2040 board from adafruit, and barring some disappointment with the documentation, I am obsessed. It is built on the RP2040, a very unique microprocessor with a killer feature: it has two Programmable IO blocks that each have 4 state machines for running I/O programs. Basically, it has two special co-processors each with room for 32 instructions and 4 independent state machines that can execute those instructions, allowing you to bit-bang I/O protocols in the low level way that said task demands without being forced to use a CPU core solely on I/O or having to worry about being fast enough for I/O and whatever actual processing you want to do.
But the really amazing feature is that these boards support CircuitPython, and adafruit has a library for using the PIO from Python. It looks super wonky, with assembly programs being written inside Python strings, but this is probably the best way to go about it.
Now, adafruit has a great guide on their library, but it does have one major omission - for my board, the QT RP2040, I could find no information on controlling the integrated RGB LED. Specifically, I could not find what GPIO pin it was wired to. After digging for a while, I found a header file with some pin declarations, and found that the RGB led is wired to pin 12, but its power is controlled by pin 11, meaning to get it working you also need to set that pin high.
So with that in mind, I modified the NeoPixel example from the guide I just linked:
# SPDX-FileCopyrightText: 2021 Scott Shawcroft, written for Adafruit Industries # # SPDX-License-Identifier: MIT import time import rp2pio import board import microcontroller import adafruit_pioasm from digitalio import DigitalInOut, Direction, Pull # NeoPixels are 800khz bit streams. Zeroes are 1/3 duty cycle (~416ns) and ones # are 2/3 duty cycle (~833ns). program = """ .program ws2812 .side_set 1 .wrap_target bitloop: out x 1 side 0 ; Side-set still takes place when instruction stalls jmp !x do_zero side 1 ; Branch on the bit we shifted out. Positive pulse do_one: jmp bitloop side 1 ; Continue driving high, for a long pulse do_zero: nop side 0 ; Or drive low, for a short pulse .wrap """ assembled = adafruit_pioasm.assemble(program) NEOPIXEL_POWER = microcontroller.pin.GPIO11 NEOPIXEL = board.GP12 # Turn on power for the NeoPixel led_power = DigitalInOut(NEOPIXEL_POWER) led_power.direction = Direction.OUTPUT led_power.value = True sm = rp2pio.StateMachine( assembled, frequency=800000 * 6, # 800khz * 6 clocks per bit first_sideset_pin=NEOPIXEL, auto_pull=True, out_shift_right=False, pull_threshold=8, ) print("real frequency", sm.frequency) for i in range(30): sm.write(b"\x0a\x00\x00") time.sleep(0.1) sm.write(b"\x00\x0a\x00") time.sleep(0.1) sm.write(b"\x00\x00\x0a") time.sleep(0.1) print("writes done") time.sleep(2)