Rshell REPL works but minicom and pyterm do not

[MK27]

I know this maybe a bit of a nitpick, but I just got two new ESP32 WROOM boards (https://www.amazon.ca/dp/B0D4X3S1LQ?ref=ppx_yo2ov_dt_b_fed_asin_title); via esptool they report as:

esptool.py v4.8.1
Serial port /dev/ttyUSB1
Connecting......
Chip is ESP32-D0WD-V3 (revision v3.1)
Features: WiFi, BT, Dual Core, 240MHz, VRef calibration in efuse, Coding Scheme None
Crystal is 40MHz

These are my first ESP32s; I've used the ESP8266 before.
I flashed v1.24.0 of the micropython firmware release from here: https://micropython.org/download/ESP32_GENERIC/

 esptool  --port /dev/ttyUSB1 --chip esp32 --baud 115200 write_flash -fm dio -z 0x1000 ESP32_GENERIC-20241025-v1.24.0.bin

I ended up doing this multiple times because of the issue described below, and if I replaced -fm dio and --baud 115200 with -fm qio and --baud 460800, connecting to the REPL failed no matter what the tool, despite the fact that the install went without error.

After I flashed one board the first time, minicom would not show a REPL prompt and was totally unresponsive; it's what I prefer to use with micropython (mostly on Pi Pico and ESP8266 boards). I have noticed in the past that sometimes when it when it would not work pyterm.py did. In this case, I got a prompt but hitting enter did not work, the only thing it responded to was ctrl-C which simply yielded another prompt.

I've actually never used rshell for the REPL so did not think of this right away. I tried the other board, same issue. I tried using the next to last micropython (v1.23.0) instead, same issue. I always used erase_flash before write_flash. I used 115200 as the explicit baud rate with both minicom and pyterm.

However, using rshell to check the filesystem worked fine; I could cat /pyboard/boot.py etc. (just 4 lines all commented out). I found out about the repl command and viola, there seems to be no problem.

So I'm happy, but I'm interested to know what explanation there is for this. Why does rshell work when minicom does not?

[robert-hh]

Why does rshell work when minicom does not?

You have to set hardware flow control off, which is a little bit tricky with minicom.

[MK27]

Cheers -- did that via the config menu (ctrl-a, z, o, "Serial port setup", "Hardware flow control" -> off) and instantly got a working prompt.

[robert-hh]

That's what I meant with tricky. No simple command line option. I prefer picocom, which is smaller and simpler, or mpremote.