Datasheet

Arduino® UNO R4 WiFi
10 / 23 Arduino® UNO R4 WiFi Modified: 22/06/2023
6.1 ESP Header
ESP header.
The header located close to the RESET button can be used to access the ESP32-S3 module directly. The pins
accessible are:
ESP_IO42 - MTMS debugging (Pin 1)
ESP_IO41 - MTDI debugging (Pin 2)
ESP_TXD0 - Serial Transmit (UART) (Pin 3)
ESP_DOWNLOAD - boot (Pin 4)
ESP_RXD0 - Serial Receive (UART) (Pin 5)
GND - ground (Pin 6)