Arduino Uno R4 WiFi

The Arduino Uno R4 WiFi is a development board based on the Renesas RA4M1 32-bit ARM Cortex-M4 microcontroller with 32KB of SRAM and 256KB of flash. It also has an Espressif ESP32-S3 coprocessor that handles USB and wireless.

Interfaces

Interface	Hardware Supported	TinyGo Support
GPIO	YES	YES
UART	YES	YES
SPI	YES	Not yet
I2C	YES	Not yet
ADC	YES	YES
PWM	YES	Not yet
USBDevice	YES	Not yet

Pins

Pin	Hardware pin	Alternative names
`D0`	`P3_01`	`UART2_RX_PIN`
`D1`	`P3_02`	`UART2_TX_PIN`
`D2`	`P1_04`
`D3`	`P1_05`	`PWM_D3_PIN`
`D4`	`P1_06`
`D5`	`P1_07`	`PWM_D5_PIN`
`D6`	`P1_11`	`PWM_D6_PIN`
`D7`	`P1_12`
`D8`	`P3_04`
`D9`	`P3_03`	`PWM_D9_PIN`
`D10`	`P1_03`	`PWM_D10_PIN`, `SPI_CS_PIN`, `CAN_TX_PIN`, `ADC_CH19_PIN`
`D11`	`P4_11`	`PWM_D11_PIN`, `SPI_SDO_PIN`
`D12`	`P4_10`	`SPI_SDI_PIN`
`D13`	`P1_02`	`LED`, `SPI_SCK_PIN`, `CAN_RX_PIN`, `ADC_CH20_PIN`
`D14`	`P0_14`	`A0`, `DAC0_PIN`, `ADC_CH9_PIN`
`D15`	`P0_00`	`A1`, `ADC_CH0_PIN`
`D22`	`P1_09`	`UART_TX_PIN`, `UART1_TX_PIN`
`D23`	`P1_10`	`UART_RX_PIN`, `UART1_RX_PIN`
`D24`	`P5_01`	`UART3_TX_PIN`, `ADC_CH17_PIN`
`D25`	`P5_02`	`UART3_RX_PIN`, `ADC_CH18_PIN`
`D26`	`P4_00`	`SCL1_PIN`
`D27`	`P4_01`	`SDA1_PIN`
`A2`	`P0_01`	`ADC_CH1_PIN`
`A3`	`P0_02`	`ADC_CH2_PIN`
`A4`	`P1_01`	`SDA_PIN`, `ADC_CH21_PIN`
`A5`	`P1_00`	`SCL_PIN`, `ADC_CH22_PIN`
`AVCC_MEASURE_PIN`	`P5_00`	`ADC_CH16_PIN`

Machine Package Docs

Documentation for the machine package for the Arduino Uno R4 WiFi

Flashing

CLI Flashing

The Uno R4 WiFi is flashed using the Arduino fork of bossac. It must be in your PATH as bossac.

Plug your Uno R4 WiFi board into your computer’s USB port.
Build and flash your TinyGo code using the tinygo flash command. This command flashes the board with the blinky example:
```
tinygo flash -target=arduino-uno-r4-wifi examples/blinky1
```
The Uno R4 WiFi board should restart and then begin running your program.

Notes

The serial console uses UART1, which the ESP32-S3 bridges to the USB port. UART2 is on the D0 and D1 header pins.

Last modified October 28, 2026: docs: update machine docs for 0.44.0 release (b77bfd3)