platformio/platformio-core

`pio device monitor` doesn't reconnect proactively when resetting ESP32

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#5231 opened on Aug 16, 2025

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device managementhelp wanted

Description

Original post to the community: https://community.platformio.org/t/how-can-pio-device-monitor-detect-disconnection/48477?u=riywo

I’m looking for a way to reconnect serial monitor automatically when the device is unplugged then plugged, or pushed the RST. Especially because I want to capture logs from setup(). I’m using Seeed XIAO ESP32 S3 from Windows 11.

Although pio device monitor has auto reconnection by default (#3939), it doesn’t recognize the disconnection itself until I hit any key. Once I hit a key, it tries to send the key and raises an exception, thus reconnects:

(I hit a key)
Disconnected (ClearCommError failed (PermissionError(13, 'The device does not recognize the command.', None, 22)))
Reconnecting to COM14    Connected!

I wonder whether we have a workaround or we can add a new feature to do some keepalive check proactively so that it can reconnect immediately?

I'll try to create a PR when I have a time, but please let me know if someone has already solved this problem.

Contributor guide

Tech stack
python
Domain
cli
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
pythonserial communication basicsplatformio core codebase
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Start by examining the existing auto reconnection logic in the `pio device monitor` implementation, particularly the code referenced in PR #3939. Look into how the serial port's connection status is monitored (e.g., via polling the port state or sending keepalive pings). The issue suggests implementing a proactive keepalive check that periodically verifies the connection, possibly by sending a small byte and checking for an error. Investigate the Python `serial` library's capabilities for detecting disconnection without data transmission. Check the serial monitor's main loop in the platformio core source to see where a check could be added.