wiki：https://docs.espressif.com/projects/esp-dev-kits/en/latest/other/esp-prog-2/index.html
This user guide will help you get started with ESP-Prog and will also provide more in-depth information.
ESP-Prog is one of Espressif’s development and debugging tools, with functions including automatic firmware downloading, serial communication, and JTAG debugging. ESP-Prog’s automatic firmware downloading and serial communication functions are supported on ESP8266, ESP32, ESP32-S2, ESP32-S3, and ESP32-C3, while the JTAG debugging is supported only on ESP32, ESP32-S2, ESP32-S3, and ESP32-C3.
ESP-Prog can be easily connected to a PC with the use of only one USB cable. Then, the PC can identify the board’s Program and JTAG interfaces (functions) by their port numbers.
Given that the power supply voltage may vary on different user boards, either of the ESP-Prog interfaces can provide 5 V or 3.3 V power supply through pin headers, in order to ensure power compatibility. Power on ESP-Prog could be toggled between 3.3 V and 5 V, but the RX/TX & JTAG signals will always be at the 3.3 V level.
