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error: espcomm_open failed



This post shows a solution to the espcomm_open failed error after clicking Upload on Linux. It also shows how to cause this error.


Symptom


After clicking Upload you see this error:


Arduino: 1.8.7 (Linux), Board: "WeMos D1 R2 & mini, 80 MHz, 921600, 4M (3M SPIFFS)"


Sketch uses 225289 bytes (21%) of program storage space. Maximum is 1044464 bytes.

Global variables use 32140 bytes (39%) of dynamic memory, leaving 49780 bytes for local variables. Maximum is 81920 bytes.

warning: espcomm_sync failed

error: espcomm_open failed

error: espcomm_upload_mem failed

error: espcomm_upload_mem failed


This report would have more information with

"Show verbose output during compilation"

option enabled in File -> Preferences.



A Solution


1. Open a terminal

2. Type fuser /dev/ttyUSB0

You should see something like:

/dev/ttyUSB0: 28988


3. Type kill -9 28988 (replace 28988 with the actual number listed)

4. Click Upload again

You should see something like:

Sketch uses 225289 bytes (21%) of program storage space. Maximum is 1044464 bytes.

Global variables use 32140 bytes (39%) of dynamic memory, leaving 49780 bytes for local variables. Maximum is 81920 bytes.

Uploading 229440 bytes from /tmp/arduino_build_91017/sketch_nov03a.ino.bin to flash at 0x00000000

................................................................................ [ 35% ]

................................................................................ [ 71% ]

................................................................. [ 100% ]



Cause Problem


In another terminal type minicom (follow [link])

Click Upload, you'll see the error



Reference


Arduino icon clipped from [link]