I have ESP8266 boards with CP2102 USB to serial IC and ESP8266 boards with CH340 USB to serial IC. On both boards automatic entering programming mode and automatic restart after programming work well.
However - when starting the Serial Monitor, ESP8266 on CP2102 boards always restarts while on CH340 boards it doesn’t restart.
Since automatic entering programming mode and automatic restart after uploading firmware on both types of boards work well I tried to reproduce the behaviour of the CP2102 boards with the CH340 boards by testing all combinations of:
monitor_rts = 0 / 1
monitor_dtr = 0 / 1
added to platformio.ini but neither combination caused reset of CH340 boards when starting Serial Monitor.
What is causing that difference in the behaviour between these boards and how to control whether starting Serial Monitor will or will not cause a reset?
The boards with CP2102 are the same as NodeMCU V2 and the boards with CH340 are the same as NodeMCU V3 in this picture:
