I need to monitor 20 esp32 for a long time ( more than 48h) to monitor crash dump.
Since with the arduino framework, it's not possible (yet) to store the dump in the flash, and I don't want to have a usb hub to 20 usb, I was thinking about a single wire connection from one pin of a master esp32, to all tx of the esp32 to monitor with softserial, copying the serial input to the serial output ( with a header to the line corresponding to the pin receiving the debug log).
the master is connected to my usb port, reading all logs at once.
In theory, this seems.... nice.
But it doesn't seem to work in practice ... I am not able to read all input with softserial at the same time.
Your Original Post gave the impression that all of the other ESP32s were connecting to a single Rx pin on the Master - which probably would not work either - unless you could control when each of the slaves was allowed to talk.
Your diagram implies that you would have several instances of SoftwareSerial. That is very unlikely to work - generally only one instance is usable. SoftwareSerial is a very poor substitute for HardwareSerial.
the objective is to detect the crashdump ( wdt) generated by my code and... by the wifi stack (using asynctcp) ...
I don't find a way to catch the coredump in another way than the serial monitor via Serial...
and the arduino framework does not support writing the coredump in the flash (yet)...
At the moment, I have 3 usb connexions to 3 esp, ( hoping that one of those 3 will fail in the next hours/days) but the rest is not monitored....