MicroPython Cooperative Scheduler

A simple, lightweight, cooperative scheduler module designed for MicroPython.

Installation

Via mip

You can install this package directly onto your MicroPython device using mip:

import mip
mip.install("github:simonl65/scheduler")

Or using mpremote:

mpremote mip install github:simonl65/scheduler

Via uv / pip (For development/simulation)

For local simulation or development, you can install the package via:

uv pip install .
# or
pip install .

Usage

Define your task functions and task list, and run the scheduler loop:

from machine import Pin
from scheduler import Task, run

led = Pin("LED", Pin.OUT)

def task_led():
    led.toggle()
    print("LED toggled")

def task_sensor():
    print("Reading sensor data")

# Set up tasks with their intervals (in milliseconds)
tasks = [
    Task(task_led, interval_ms=1000),
    Task(task_sensor, interval_ms=500),
]

# Build the generator once, outside the loop.
# Setting light_sleep=True will sleep between task rounds to save power.
scheduler = run(tasks, light_sleep=True)

while True:
    next(scheduler)

A task's exception is isolated by default -- caught and stashed on task.last_exception so one failing callback doesn't stop the round or later tasks in it. Pass Task(..., isolate_errors=False) for a task whose failure must propagate and stop the loop instead.

light_sleep caveat

light_sleep=True calls machine.lightsleep() between rounds, which stops the device responding to everything outside of a Task callback for up to the soonest task's remaining interval -- including any UART, SPI, or other peripheral serviced by application code between next(scheduler) calls. Bytes arriving during the sleep are lost with no indication to the caller. Only enable it on a device where all I/O happens inside Task callbacks.