CircuitPython asyncio with task added later

code.py

#3 no gather, and add a task later
import board
import digitalio
import asyncio
import adafruit_ticks

led_pins = [board.A0, board.A1, board.A2, board.A3]
extra_led_pin = board.D24

async def do_led(pin):
    led = digitalio.DigitalInOut(pin)
    led.switch_to_output(False)
    while True:
        led.value = not led.value
        await asyncio.sleep(led_pins.index(pin) + 0.25)

async def main():
    tasks = []
    for taskno in range(len(led_pins)):
        tasks.append(asyncio.create_task(do_led(led_pins[taskno])))

    done_once = False
    t = adafruit_ticks.ticks_ms()

    # This will run forever, because no tasks ever finish.
    # await asyncio.gather(*tasks)
    while True:
        # add a task after running for a bit
        # move this to its own task, and delete that task when done once...
        if not done_once and (adafruit_ticks.ticks_ms() - t > 10_000):  # 10 sec
            led_pins.append(extra_led_pin)
            tasks.append(asyncio.create_task(do_led(led_pins[-1])))
            done_once = True
        await asyncio.sleep(0)

asyncio.run(main())

async_leds.mov

(yellow wire is connected to board.D24)

#2 no gather, all tasks created at the start
import board
import digitalio
import asyncio

led_pins = (board.A0, board.A1, board.A2, board.A3)
extra_led_pin = board.D24

async def do_led(pin):
    led = digitalio.DigitalInOut(pin)
    led.switch_to_output(False)
    while True:
        led.value = not led.value
        await asyncio.sleep(led_pins.index(pin) + 0.25)

async def main():
    tasks = []
    for taskno in range(len(led_pins)):
        tasks.append(asyncio.create_task(do_led(led_pins[taskno])))

    # This will run forever, because no tasks ever finish.
    # await asyncio.gather(*tasks)
    while True:
        await asyncio.sleep(0)

asyncio.run(main())

#1 canonical version, with gather
import board
import digitalio
import asyncio

led_pins = (board.A0, board.A1, board.A2, board.A3)
extra_led_pin = board.D24

async def do_led(pin):
    led = digitalio.DigitalInOut(pin)
    led.switch_to_output(False)
    while True:
        led.value = not led.value
        await asyncio.sleep(led_pins.index(pin) + 0.25)

async def main():
    tasks = []
    for taskno in range(len(led_pins)):
        tasks.append(asyncio.create_task(do_led(led_pins[taskno])))

    # This will run forever, because no tasks ever finish.
    await asyncio.gather(*tasks)

asyncio.run(main())