can't connect /dev/serial0

[Daniel Perron]

I'm using micropython in serial mode only, No USB,  on the Pico and I'm force to rename /dev/ttyS to /dev/ttyAMA0 

Why is /dev/serial0 not use, or available, instead of /dev/ttyAMA0 ?  

[Mickey Mx]

Check your Pico, make sure your PC as the driver for the Pico USB-UART bridge chip (CH340, CP2102, etc.).

[Daniel Perron]

I think that you didn't read my email properly.  I'm using my pico on USB host right now. 

I change the behavior of micropython so the USB port is reading my USB gamepad.

Because of that my USB port is not able to communicate via the USB. 

I recompile the Micropython code to enable the uart for  REPL to GP0&1.

The problem I'm facing is that the PI4 /dev/ttyAMA0 is for the bluetooth and it is not the tty serial anymore because it is /dev/ttyS.

To fix this issue the raspberryPi foundation ask us to use /dev/serial0 instead. This way any Raspberry Pi board will be the same.

/dev/serial0 assure us that the serial  is on  GPIO14 & 15 .  

[Andy Piper]

Is this a MicroPython issue or a Thonny issue?

If I understand correctly I think you're saying you need to modify MicroPython directly? Maybe worth raising this in the MicroPython forums (GitHub Discussions -> https://github.com/orgs/micropython/discussions)

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[guy colin]

Daniel is right, Thonny as any software when running on a Raspberry Pi must use /dev/serial0 to access the serial port.

/dev/serial0 is a link pointing to the correct serial port. The Raspberry Pi OS is managing this link, because depending of the Pi model the actual serial port may not be the same.

[Aivar Annamaa]

Thonny uses Pyserial library for detecting the available serial ports and communicating with them. Therefore only the ports listed by Pyserial are considered as possible communication targets.

Best regards,
Aivar

[Daniel Perron]

this is a problem.

Maybe  if we have the possibility in the option menu to type the device we want this will go around it.

[Aivar Annamaa]

If you can confirm that Pyserial is able talk to your device, then I could add /dev/serual0 to the list of option if the file exists.

Best regards,
Aivar

[Daniel Perron]

Ok this is from my micropython version which is UART enable

#define MICROPY_HW_ENABLE_UART_REPL             (1)   // UART enable
#define MICROPY_HW_ENABLE_USBDEV                (0)      // USB OFF  (I'm using it in USB_HOST_MODE)

The script using Pyserial,

import serial
com = serial.Serial('/dev/serial0',baudrate=115200,timeout=1)
#Send import command via /dev/serial0
com.write("import os\r".encode("utf-8"))
returnChars = com.read(100).decode("utf-8")
print(returnChars)
#"Send os.uname via /dev/serial0
com.write("os.uname()\r".encode("utf-8"))
returnChars = com.read(200).decode("utf-8")
print(returnChars)
#Send help('modules') via /dev/serial0
com.write("help('modules')\r".encode("utf-8"))
returnChars = com.read(3000).decode("utf-8")
print(returnChars)

And the result when I run it from the Pi

pi@benchpi4:~ $ python3 confirmserial0.py
import os
>>>
os.uname()
(sysname='rp2', nodename='rp2', release='1.19.1', version='v1.19.1-375-ge90b85cc9-dirty on 2022-09-08 (GNU 8.3.1 MinSizeRel)', machine='Raspberry Pi Pico with RP2040')
>>>
help('modules')
__main__          gamepad           uasyncio/funcs    ujson
_boot             gc                uasyncio/lock     umachine
_boot_fat         math              uasyncio/stream   uos
_onewire          micropython       ubinascii         urandom
_rp2              neopixel          ucollections      ure
_thread           onewire           ucryptolib        uselect
_uasyncio         rp2               uctypes           ustruct
builtins          uarray            uerrno            usys
cmath             uasyncio/__init__ uhashlib          utime
dht               uasyncio/core     uheapq            uzlib
framebuf          uasyncio/event    uio
Plus any modules on the filesystem
>>> 

You should read Raspberry Pi UART.   This tell that /dev/serial0 will be always the primary UART which depends of the Pi model.

Old PI use /dev/ttyAMA0 on GPIO14&15 but the PI3 &PI4 use /dev/ttyS0

regards,

Daniel Perron

[Aivar Annamaa]

Alright, I'll add more options to choose from in the next release (https://github.com/thonny/thonny/issues/2459)

The page you linked to, sais: "/dev/serial0 and /dev/serial1 are symbolic links which point to either /dev/ttyS0 or /dev/ttyAMA0". What do you think -- should I add all these 4 (if present) or only the symlinks? At the moment, on my machine with nothing attached, I see /dev/ttyS0 but neither /dev/serial0 nor /dev/serial1.

Best regards,
Aivar

[Daniel Perron]

The page you linked to, sais: "/dev/serial0 and /dev/serial1 are symbolic links which point to either /dev/ttyS0 or /dev/ttyAMA0". What do you think -- should I add all these 4 (if present) or only the symlinks? At the moment, on my machine with nothing attached, I see /dev/ttyS0 but neither /dev/serial0 nor /dev/serial1.

      Good question!
     
       Maybe just a way to type any device we want. Right now we are forced to select from a choice.

[Aivar Annamaa]

On Thursday, September 15, 2022 at 5:49:07 PM UTC+3 daniel...@gmail.com wrote: 

       Maybe just a way to type any device we want. Right now we are forced to select from a choice.

This would require changing the UI widget (note that currently it does not contain simply the port, but also some extra information). I'd rather add more items to the choice.