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Serial monitor cannot find port


Have a problem with monitor port autodetection. Upload works fine but monitor cannot find port. Please help.

viktor@Black-pro-4:~/Documents/PlatformIO/Projects/Test $ cat platformio.ini
platform = espressif8266
board = esp12e
framework = arduino
upload_port = /dev/cu.wchusbser*
upload_speed = 921600
monitor_speed = 115200
monitor_port = /dev/cu.wchusbser*
viktor@Black-pro-4:~/Documents/PlatformIO/Projects/Test $ ls -l /dev/cu.wchusbser*
crw-rw-rw-  1 root  wheel   19,  29 Jun 28 20:17 /dev/cu.wchusbserial14140
viktor@Black-pro-4:~/Documents/PlatformIO/Projects/Test $ ~/.platformio/penv/bin/platformio device monitor
could not open port '/dev/cu.wchusbser*': [Errno 2] could not open port /dev/cu.wchusbser*: [Errno 2] No such file or directory: '/dev/cu.wchusbser*'
viktor@Black-pro-4:~/Documents/PlatformIO/Projects/Test $

I don’t think it does shell path expansion when passing the monitor device to

Works when used as upload_port and monitor_port?

Also PIO should try and autodetect the correct port automatically, so you don’t need to specify it.

Sorry, I use platformio for a 2 days for now and not too familiar with it yet, but I bet it was working yesterday ))
Also from the docs :

Sure, if I specify exact path to the port, it works fine. The problem is, that ch341 driver changes the port name in case… I don’t really know when, but quite often )))
In case I do not specify the monitor_port at all, it lists me all available ports prompting to choose which one shall I use - each time, a bit annoying.

If the wildcards don’t work (which I didn’t know exist), then something is broken. Open an issue at with the exact hardware you’re using.

Ok, was not sure is it issue or just me doing something wrong. Thank you!

monitor_port wildcards are new for PIO 4… so if the OP isn’t using the 4.0 beta, it won’t work. PIO 4 should go live in the next few days or week, so probably best to just wait for that.

1 Like

well, ok, thank you!