Robot Maker Toolkit › Pinouts › Arduino UNO R4 WiFi

Arduino UNO R4 WiFi pinout

Every Arduino UNO R4 WiFi pin with its capabilities (digital, PWM, ADC, I2C, SPI, UART) and the wiring gotchas that bite. The modern UNO: still 5 V and shield-compatible, but with WiFi/Bluetooth, a real DAC, CAN bus and a 12x8 LED matrix on board.

Renesas RA4M1 @ 48 MHz + ESP32-S3 (WiFi/BLE)Logic: 5 VFree in app

Pin	Capabilities	Watch out
D0 (RX)	DigitalUART RX
D1 (TX)	DigitalUART TX
D2	DigitalInterrupt
D3	DigitalPWMInterrupt
D4	DigitalCAN TX
D5	DigitalPWMCAN RX
D6	DigitalPWM
D9	DigitalPWM
D10	DigitalPWMSPI SS
D11	DigitalPWMSPI MOSI
D12	DigitalSPI MISO
D13	DigitalSPI SCKBuilt-in LED
A0	Analog inDAC out 12-bit	True analog output — not on other UNO pins
A1	Analog in
A2	Analog in
A3	Analog in
A4	Analog inI2C SDA
A5	Analog inI2C SCL
5V	Power out 5V
3.3V	Power out 3.3V	Lower current than the 5V rail
VIN	Power in 6–24V	R4 accepts up to 24V on VIN
GND	Ground

Arduino UNO R4 WiFi gotchas & notes

5 V logic and the classic UNO footprint — existing shields and 5 V modules still work.
A0 is a true 12-bit DAC (analogWrite to A0 outputs an analog voltage), not just PWM.
WiFi and Bluetooth are handled by an onboard ESP32-S3; use the WiFiS3 library.
Qwiic/STEMMA I2C connector on board; SDA/SCL also on A4/A5.
PWM (analogWrite) on ~3, 5, 6, 9, 10, 11.

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