I’m trying to use an ESP-Prog to debug a sketch running on an ESP32 with an ILI9341 touchscreen on a pre-built board, which connects ESP32 and the touchscreen.
While debugging a simple blink-demo (without the touchscreen) works fine, the debug session can’t be established when all components (ESP32, Touchscreen and ESP-Prog) are connected. First I was a little bit puzzled, 'til I recognized that the reason is the usage of the GPIOs 14 and 15 which were used by the board designer (not me
) to control background light of the touchscreen resp. as chip select for the touchscreen. Unfortunately these ports are obviously part of the JTAG interface of the ESP32 (TMS/TDO).To avoid this clash I saw two (theoretical) solutions. Separating the PCB-tracks for background light and CS and reconnecting them to alternate GPIOs (16 and 17 look fine) or reassigning TMS/CDO to these GPIOs - may be via something like PIN_FUNC_SELECT. However after reading some docs I am in doubt that the latter is possible, because - as far as I understood - reassigning JTAG lines, which are connected via IO_MUX, is not as free as it would be if they were connected to the GPIO matrix.
Just to be sure - could somebody please confirm that I have understood that correctly - or otherwise tell me how to proceed?
Kind regards
arduhe