UART Repl Virtual Terminal Help / Possible Bug

[PsuFan]

Is anyone familiar with the repl virtual terminal? I'm writing a program that accesses the repl via uart just like putty but allows me to upload and download files like ampy. Why? Because ampy SUCKS and you have to close putty to upload a program. It was going really well until I got to Control+E Paste mode. The commands start behaving completely different. I dont understand how putty knows what mode its in, it doesn't send any commands to tell it that its in a different mode but backspace doesn't send ^[K to erase to end of line.

Also the bug part, even in putty, you are allowed to backspace over the === which causes an error. Invalid syntax I think. This is not allowed in normal mode with >>>

[shariltumin]

We have two REPL modes in MicroPython: 1) REPL, and 2) raw REPL. The second mode is for program to program script transfer and execution, like ampy and your program with MicroPython firmware.

Have you tried mpremote? With mpremote you can do:

mpremote mount .

You can run your scripts without making copies on your board. Good for development and testing.

But it is up to you, there is a useful learning process to be gained here. To make your program work properly, you need to handle different REPL modes, especially the raw REPL.

[PsuFan]

Yeah I don’t have a problem with the raw repl, I use it for upload and download. They could have used more consistent and more unique terminators… never heard of mpremote. Can I be in repl and send files at the same time?

[Josverl]

Can I be in repl and send files at the same time?

No, as that is practically impossible without rewriting the repl to include and allow file transfers.

Mpremote avoids needing to do file transfers, by running a virtual filesystem on the MCU that accesses the files on the host.

TLDR, it (mpremote mount .) accomplishes the (short inner loop) dev workflow you want, without needing to update files on the MCU.

Just need to copy them once, after you are finished developing

[PsuFan]

@Josverl but can I be in the repl while mounted? I’m doing it with my program, you can’t use them at the same time but I don’t have to keep leaving and entering repl to upload.

[Josverl]

Yes you can !
First mount a folder, then repl : mpremote mount <folder> repl

the folder will even be remounted after a soft reboot ( Ctrl-D)

 D:\mypython\pico_w\src> mpremote mount . repl
Local directory . is mounted at /remote
Connected to MicroPython at COM31
Use Ctrl-] or Ctrl-x to exit this shell
>
MicroPython v1.24.1 on 2024-11-29; ESP32C3 module with ESP32C3
Type "help()" for more information.
>>> import os
>>> os.getcwd()
'/remote'
>>> os.listdir()
['lib', 'main.py', 'mqtt_local_example.py', 'tst_mqtt.py', 'wifi.py', '_secrets.py', '_secrets_sample.py']
>>>

re-mounting may go off if you have a boot.py/main.py that get in the way of remounting.

so you can edit your code an IDE, such as VScode ( with linting,typechecking, AI support etc etc
and run the above in a terminal to get :

When you are done , and want to deploy / test on a device in isolation
then you copy the files to the device
from the src folder mpremote cp -r . :

[shariltumin]

Perhaps I can show you a simple example.

$ cd ~/micropython/scripts/tests/tool_test
$ ls
ESP8266  pow.py
$ mpremote a0 mount .
Local directory . is mounted at /remote
Connected to MicroPython at /dev/ttyACM0
Use Ctrl-] or Ctrl-x to exit this shell
>
MicroPython v1.25.0-preview.442.g3805e65ed.dirty on 2025-04-05; Raspberry Pi Pico with RP2040
Type "help()" for more information.
>>> import os
>>> os.listdir()
['pow.py', 'ESP8266']
>>> with open('ESP8266/pow.mpy', 'rb') as f:
...     w = f.read(10)
...     print(w)
... 
b'M\x06\x00\x1f\t\x00\x0cpow'
>>> import pow
2.828427
>>> with open('test.txt', 'w') as f:
...     f.write('Hello World!')
... 
12
>>> Ctrl-x
$ cat test.txt 
Hello World!

What you want to do already exists. But as I said, if you have the time and the will, please continue. Or maybe you have some other features you want to implement. We learn by doing!

$ mpremote --help
mpremote -- MicroPython remote control
See https://docs.micropython.org/en/latest/reference/mpremote.html

List of commands:
  connect     connect to given device
  disconnect  disconnect current device
  edit        edit files on the device
  eval        evaluate and print the string
  exec        execute the string
  fs          execute filesystem commands on the device
  help        print help and exit
  mip         install packages from micropython-lib or third-party sources
  mount       mount local directory on device
  repl        connect to given device
  resume      resume a previous mpremote session (will not auto soft-reset)
  rtc         get (default) or set the device RTC
  run         run the given local script
  sleep       sleep before executing next command
  soft-reset  perform a soft-reset of the device
  umount      unmount the local directory
  version     print version and exit

List of shortcuts:
  --help      
  --version   
  a0          connect to serial port "/dev/ttyACM0"
  a1          connect to serial port "/dev/ttyACM1"
  a2          connect to serial port "/dev/ttyACM2"
  a3          connect to serial port "/dev/ttyACM3"
  bootloader  make the device enter its bootloader
  c0          connect to serial port "COM0"
  c1          connect to serial port "COM1"
  c2          connect to serial port "COM2"
  c3          connect to serial port "COM3"
  cat         
  cp          
  devs        list available serial ports
  df          
  ls          
  mkdir       
  reset       hard reset the device
  rm          
  rmdir       
  sha256sum   
  touch       
  u0          connect to serial port "/dev/ttyUSB0"
  u1          connect to serial port "/dev/ttyUSB1"
  u2          connect to serial port "/dev/ttyUSB2"
  u3          connect to serial port "/dev/ttyUSB3"