📋 Overview
The UNO R4-Compatible WiFi Board is a UNO-form-factor development board built around the same core chipset used in the official Arduino UNO R4 WiFi: a 32-bit Renesas RA4M1 (R7FA4M1AB3CFM) microcontroller paired with an ESP32-S3 module for Wi-Fi and Bluetooth. This is a compatible clone, not a genuine Arduino-branded product — but it uses the identical microcontroller and wireless chipset, so it runs the same libraries, sketches, and board-level projects you'll find across the maker community.
The board uses a dual-MCU design: the RA4M1 handles all of your sketch logic, digital/analog I/O, and onboard peripherals (DAC, op-amp, CAN controller), while a separate dual-core ESP32-S3 coprocessor manages Wi-Fi and Bluetooth 5 connectivity. The two chips talk to each other over an internal logic-level bridge, so from your code's perspective, wireless features are accessed through simple, built-in libraries — no separate shield required.
On top of the wireless upgrade, this board keeps the classic 5V UNO operating voltage and pin layout for shield compatibility, while adding a built-in 12x8 LED matrix, a 12-bit DAC, an onboard op-amp, a USB-C port, a Qwiic I2C connector, and CAN bus support — making it a strong upgrade path for anyone moving up from an 8-bit UNO board into IoT, audio, or automotive-style projects.
⭐ Key Features
- Renesas RA4M1 Microcontroller — 32-bit Arm Cortex-M4 running at 48 MHz with floating point unit (FPU), 256 kB flash, 32 kB SRAM, and 8 kB EEPROM
- ESP32-S3 Wi-Fi & Bluetooth Coprocessor — Dual-core module providing Wi-Fi 4 (802.11 b/g/n, 2.4 GHz) and Bluetooth 5 LE, with no extra shield needed
- Built-In 12x8 LED Matrix — 96 programmable red LEDs for animations, scrolling text, sensor readouts, and simple games
- 12-Bit DAC & Onboard Op-Amp — For generating analog waveforms (like sawtooth or audio signals) and buffering/amplifying analog signals
- USB-C, Qwiic I2C & CAN Bus — Modern USB-C programming/power port, plug-and-play Qwiic I2C connector, and a CAN controller for automotive/industrial-style projects (external transceiver required)
- Full UNO Shield Compatibility — Same 5V operating voltage and pin layout as classic UNO boards, so most existing shields and accessories still work
📡 How the Dual-MCU Design Works
This board doesn't use one chip to do everything — it splits the work between two microcontrollers that communicate internally:
- RA4M1 (Main MCU) — Runs your Arduino sketch, controls all digital/analog pins, the LED matrix, DAC, op-amp, and CAN controller. Operates at 5V, matching classic UNO boards.
- ESP32-S3 (Wireless Coprocessor) — A separate, dual-core chip dedicated to Wi-Fi and Bluetooth. It operates at 3.3V and is not directly accessible from your pin headers.
- Logic-Level Bridge — Because the two chips run at different voltages (5V vs. 3.3V), an internal logic-level translator lets them exchange data safely without you needing to manage the voltage difference yourself.
- USB Programming Path — By default, USB communication for programming is routed through the ESP32-S3 module before reaching the RA4M1. This is normal and doesn't require any special setup for typical use.
📝 Note: Because the RA4M1 (main MCU) is single-core and the ESP32-S3 (wireless coprocessor) is dual-core, we describe this board as having a "dual-MCU" architecture with a dual-core wireless coprocessor — not a single dual-core chip. This is a more accurate description than calling the whole board "dual-core."
📌 Module Pinout
Looking at the board from the top, with the USB-C port and DC jack at the top-left and the digital header along the top edge:
| Pin | Label | Function |
|---|---|---|
| D0 / D1 | RX / TX | UART Serial Receive / Transmit |
| D2, D3 | Digital / Interrupt | GPIO with external interrupt support |
| D3, D5, D6, D9 | PWM (~) | PWM-capable digital pins |
| D4 | Digital | General purpose GPIO |
| D10 | CANTX0 | CAN Bus Transmit (requires external transceiver) |
| D11–D13 | SPI / SCK | SPI Controller Out/In, Clock (D13 doubles as CANRX0) |
| D13 | CANRX0 | CAN Bus Receive (requires external transceiver) |
| SDA / SCL | Digital header I2C | Standard I2C bus (also on A4/A5) |
| A0 | Analog In / DAC | Analog input 0 or 12-bit DAC output |
| A1 / A2 / A3 | OPAMP+ / OPAMP− / OPAMP Out | Onboard operational amplifier connections |
| A4 / A5 | SDA / SCL | Standard I2C bus (shared with digital header) |
| Qwiic Connector | SCL / SDA / 3V3 / GND | Secondary I2C bus, 3.3V only |
| VIN | Power In | 6–24V input (barrel jack or header) |
| USB-C | Power / Data | 5V power, programming, and serial communication |
| +5V / +3V3 | Power Out | Regulated power rails for external components |
⚠️ Important: The ESP32-S3 coprocessor and its dedicated header operate at 3.3V and are not 5V tolerant. Never connect a 5V signal to the ESP header or the Qwiic connector — doing so can permanently damage the ESP32-S3 module. Keep 3.3V and 5V circuits separate on this board.
📊 Specifications
| Main Microcontroller | Renesas RA4M1 (R7FA4M1AB3CFM), 48 MHz Arm Cortex-M4 with FPU |
| Wireless Module | ESP32-S3-MINI-1-N8, dual-core Xtensa LX7, Wi-Fi 4 (2.4 GHz) & Bluetooth 5 LE |
| Flash / SRAM / EEPROM | 256 kB / 32 kB / 8 kB |
| Operating Voltage | 5V (RA4M1) / 3.3V (ESP32-S3, internal only) |
| Input Voltage (VIN) | 6–24V (barrel jack or header) |
| USB Input Voltage | 4.8–5.5V via USB-C (do not exceed 5V) |
| Digital I/O Pins | 14, each rated up to 8 mA max |
| Analog Input Pins | 6 (A0–A5) |
| DAC Resolution | Up to 12-bit (on pin A0) |
| LED Matrix | 12x8 (96 LEDs), red, charlieplexed |
| Communication | 1x UART, 1x SPI, 2x I2C (incl. Qwiic), 1x CAN (external transceiver required) |
| USB Connector | USB-C |
| Operating Temperature | -40°C to +85°C |
| Board Dimensions | Approx. 68.6 × 53.3 × 15 mm (2.70 x 2.10 x 0.59 inches) L × W × H |
🔌 CAN Bus Wiring
The RA4M1's CAN controller is built into the microcontroller, but it has no onboard transceiver — you'll need an external CAN transceiver module (such as an SN65HVD230) to connect to an actual CAN bus network.
| Board Pin | CAN Transceiver Pin |
|---|---|
| D13 (CANRX0) | CAN RX |
| D10 (CANTX0) | CAN TX |
| 3.3V | VIN |
| GND | GND |
Between two CAN transceivers, connect CANH to CANH and CANL to CANL. The onboard CAN library supports standard bit rates of 125k, 250k, 500k, and 1000k bps.
📝 Note: A CAN transceiver is required for this board to communicate on a real CAN bus network — the pins alone will not work without one.
🔌 Compatible With
- Arduino IDE (Desktop) and Arduino Cloud Editor, using an RA4M1-compatible board package
- Existing 5V UNO-format shields and accessories
- Qwiic-standard I2C sensor and actuator modules (3.3V only)
- External CAN transceiver modules (e.g., SN65HVD230)
🎯 Typical Applications
- IoT and smart home projects using built-in Wi-Fi and Bluetooth
- Visual feedback and status displays using the onboard LED matrix
- Audio signal generation and simple analog projects using the 12-bit DAC
- Automotive, robotics, or industrial prototyping using CAN bus
- STEM education and general-purpose learning projects
- Upgrading existing 8-bit UNO shield-based projects to more memory and speed
🚀 Getting Started
- Install the Arduino IDE (Desktop) or use the Arduino Cloud Editor
- Connect the board to your computer using a USB-C cable
- Install the appropriate RA4M1-based board package for UNO R4 WiFi-compatible boards
- Select the correct board and port, then upload a simple sketch (like Blink) to confirm everything is working
💡 Tip: If a sketch locks up the board and it's no longer reachable over USB, double-tap the reset button right after powering up to enter bootloader mode for recovery.
⚠️ Important Notes
- Do not power the board with more than 5V through the USB-C port
- Never connect a 5V signal to the ESP32-S3 header or the Qwiic connector — both are 3.3V only and not 5V tolerant
- Digital GPIO pins are rated for a maximum of 8 mA — use an external driver or power supply for higher-current loads like motors or servos
- A4/A5 are shared with the main I2C bus — avoid using them as analog inputs while I2C devices are active on that bus
- CAN bus functionality requires an external transceiver module; it will not work with the pins alone
- Operating temperature range is -40°C to +85°C; USB input should stay within 4.8–5.5V
🏪 Where to Buy
Buy the UNO R4-Compatible WiFi Board at Envistia Mall.
Buy Now- 📦 Fast US Shipping
- 🔄 Hassle-Free Returns
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📚 Documentation & Resources
- Arduino Uno R4 Wifi Documentation at arduino.cc
⚠️ Disclaimer
This guide is provided for educational purposes to help you get started with the UNO R4-Compatible WiFi Board. Envistia Mall makes no warranty regarding the accuracy or completeness of third-party software, libraries, or board packages referenced here. Always follow proper electrical safety practices when wiring or powering this board — incorrect voltage or wiring can permanently damage the board, connected components, or pose a risk of injury. Specifications are based on the manufacturer's reference chipset documentation and may vary slightly between production batches or firmware/board-package versions. This product is a compatible clone using the same RA4M1 and ESP32-S3 chipset as certain officially branded boards, but is not manufactured, endorsed, or affiliated with the original brand owner.