Arduino UNO R4 WiFi

Arduino® UNO R4 WiFi
11 / 23 Arduino® UNO R4 WiFi Modified: 26/06/2023
ESP header (schematic)
6.2 USB Bridge
When programming the UNO R4 WiFi, the RA4M1 MCU is programmed via the ESP32-S3 module by default. The U2
and U6 switches can switch the USB communication to go directly to the RA4M1 MCU, by writing a high state to the
P408 pin (D40).
Soldering together the SJ1 pads permanently sets the USB communication directly to the RA4M1, bypassing the
ESP32-S3.