micropython / micropython/micropython-lib

Cannot init USB devices in boot.py

Open
#882 8 comments 1 reaction 0 assignees View on GitHub

Nobody has claimed this yet.

bug
Dominant language
Python
Stars
2.9k
Forks
1.1k
Avg merge
7d 6h
Merged PRs (30d)
3

Description

I tested this on a pico running MP 1.23 and the latest release of usb-device-cdc.

boot.py:

import usb.device
from usb.device.cdc import CDCInterface

IFACE_TWO = CDCInterface()
IFACE_TWO.init(timeout=0)
#usb.device.get().init(IFACE_TWO, builtin_driver=True)

main.py:

from time import sleep_ms

def main():
	while True:
		print(IFACE_TWO)
		sleep_ms(1000)

if __name__ == "__main__": main()

Running this as-is, IFACE_TWO does show up in main.py, but uncommenting the init function causes the process to error out. This discord post suggests you can call usb.device.get.init() in boot.py, is this no longer true?

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the example using boot.py and main.py on MicroPython 1.23 with the latest usb-device-cdc release. Start by tracing usb.device.get().init() and CDCInterface.init(timeout=0) to compare initialization in boot.py with later execution. Done when the supported boot.py behavior is established and the process error is fixed or clearly documented.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
embedded-iot
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.