JTAG pins
Some ESP32 devices (e.g. ESP32 C3 and S3) default to JTAG assignment of the IO pins via the IO matrix and the pins won’t work as general IO until you call gpio_reset_pin():
gpio_reset_pin(GPIO_NUM_4); //Remove JTAG default assignment
USB pins
Some ESP32 devices (e.g. ESP32 S3) default to USB of their IO pins via the IO matrix and the pins won’t work as general IO until you call gpio_reset_pin():
gpio_reset_pin(GPIO_NUM_19); //Remove USB default assignment
gpio_reset_pin(GPIO_NUM_20); //Remove USB default assignment
