Arduino UNO R4 Minima VS WiFi- What’s the Difference?

Last updated on July 30th, 2023 at 02:34 pm

Arduino UNO R4 Minima and WiFi are the latest addition to the popular UNO series boards. In this article, we will compare these two boards: their specs, pinout, and unique features.

So what’s the difference between Arduino UNO R4 Minima and WiFi?

Arduino UNO R4 WiFi has an additional ESP32-S3 chip for wireless connectivity, a 12×8 LED matrix, and a Qwiic I2C connector, priced at $27.50. Whereas R4 Minima is the basic version with no such features, priced at $20. So, R4 WiFi has everything a R4 Minima board has, but R4 Minima doesn’t.

DifferenceR4 MinimaR4 WiFi
WiFi ConnectivityNOYES
BluetoothNOYES
12×8 LED MatrixNOYES
Price$20$27.50
MicrocontrollerArm Cortex- M4 Arm Cortex- M4 +
ESP32-S3 Mini
CAN BusYESYES
QWiic connectorNOYES
RTCYESYES
RTC pinsNOYES
Difference between Arduino UNO R4 Minima and WiFi

Arduino UNO R4 Minima VS WiFi- Specifications

Differences in their specifications are listed below:

SpecR4 MinimaR4 WiFi
MicrocontrollerRenesas RA4M1Renesas RA4M1
WiFi-Bluetooth moduleNOESP32-S3 Mini
USB PortUSB-CUSB-C
Digital I/O Pins1414
Analog input pins6(14-bit)6(14-bit)
DAC1(12-bit)1(12-bit)
PWM pins6(12-bit)6(12-bit)
CAN Bus11
Input voltage (VIN)6-24 V6-24 V
Memory256 kB Flash, 32 kB RAM256 kB Flash, 32 kB RAM
ESP: 384 kB ROM, 512 kB SRAM
Clock speed48 MHz48 MHz
ESP: 240 MHz
Dimensions68.58 x 53.44 mm68.58 x 53.44 mm
Comparing the specs of R4 Minima VS R4 WiFi

Hardware Overview- R4 Minima VS R4 WiFi

Both R4 Minima and WiFi follow the same form factor as the previous R3 board. But there are many hardware differences between these two.

Main Microcontroller

Renesas RA4M1 in UNO R4
Renesas RA4M1

Both boards have a powerful 32-bit Arm Cortex-M4 microcontroller(Renesas RA4M1) with a clock frequency of up to 48 MHz. The main features of Renesas RA4M1 are listed below:

  • 256 KB code flash memory
  • 8 KB data flash memory
  • 32-KB SRAM
  • 14-bit A/D Converter (ADC14)
  • 12-bit D/A Converter (DAC12)
  • Realtime Clock (RTC)
  • Up to 84 input/output pins
  • VCC: 1.6 to 5.5 V

WiFi & Bluetooth connectivity

ESP32-S3 Mini on UNO R3 WiFi
ESP32-S3 Mini on UNO R3 WiFi

Arduino UNO R4 WiFi has another microcontroller- ESP32-S3 Mini with a clock frequency of up to 240 MHz. The ESP32-S3 chip has two main functions: giving the board WiFi+Bluetooth functionality and acting as a serial bridge for the main microcontroller. Given below are its main features:

  • 384 KB ROM & 512 KB SRAM
  • 802.11 b/g/n; Bit rate: 802.11n up to 150 Mbps
  • Bluetooth LE: Bluetooth 5, Bluetooth mesh
  • On-board PCB antenna
  • VCC: 3.0 ~ 3.6 V

ESP Header: Can be used to access the ESP32 pins directly from here.

USB-C connector

Both boards are equipped with a USB-C connector. This is helpful because USB-C is very popular and commonly used nowadays. So no need to purchase a cable separately just for programming the UNO.

This is a significant upgrade to the old type-B USB connector.

12×8 onboard LED Matrix

R4 WiFi has an onboard 12×8 LED matrix which is programmable and connected using the technique known as Charlieplexing. There are a total of 96 LEDs.

These LEDs can be accessed as an array using a specific library. See the mapping below:

UNO R4 WiFi LED matrix mapping
UNO R4 WiFi LED matrix mapping

This matrix has multiple applications and supports animation, basic game designs, scrolling text, and more.

Qwiic Connector

WiFi version of UNO R4 has an onboard I2C connector as well. It is connected to a secondary I2C bus on the board and is powered via 3.3 V.

Qwiic connector is a plug-and-play interface designed to simplify the process of connecting various sensors, modules, and other electronic components to a microcontroller or development board. It uses a simple four-wire connection for power, ground, and communication(I2C protocol).

QWiic connector
QWiic connector

With Qwiic, you don’t need to solder or deal with complicated wiring, which is great for beginners and experienced users who want to quickly prototype and connect components.

This connector is absent in R4 Minima.

Pinout- R4 Minima VS WiFi

The pin diagram of Arduino UNO Minima and WiFi shows that though the GPIO pins are identical, R4 WiFi has additional onboard connectors/pins due to the presence of ESP32-S3 chip. Their pinout is given below:

Arduino UNO R4 Minima Pinout
Arduino UNO R4 Minima Pinout
Arduino UNO R4 WiFi Pinout
Arduino UNO R4 WiFi Pinout

Conclusion- Arduino UNO R4 Minima VS WiFi

Arduino UNO R4 WiFi has an additional ESP32-S3 chip for wireless connectivity, a 12×8 LED matrix, and a Qwiic I2C connector, priced at $27.50. Whereas R4 Minima is the basic version with no such features, priced at $20. So, R4 WiFi has everything a R4 Minima board has, but R4 Minima doesn’t.

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Ankit Negi

I am an electrical engineer by profession who loves to tinker with electronic devices and gadgets and have been doing so for over six years now. During this period, I have made many projects and helped thousands of students through my blog and YouTube videos. I am active on Linkedin and Facebook.

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