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.
| Difference | R4 Minima | R4 WiFi |
| WiFi Connectivity | NO | YES |
| Bluetooth | NO | YES |
| 12×8 LED Matrix | NO | YES |
| Price | $20 | $27.50 |
| Microcontroller | Arm Cortex- M4 | Arm Cortex- M4 + ESP32-S3 Mini |
| CAN Bus | YES | YES |
| QWiic connector | NO | YES |
| RTC | YES | YES |
| RTC pins | NO | YES |
Table of Contents
Arduino UNO R4 Minima VS WiFi- Specifications
Differences in their specifications are listed below:
| Spec | R4 Minima | R4 WiFi |
| Microcontroller | Renesas RA4M1 | Renesas RA4M1 |
| WiFi-Bluetooth module | NO | ESP32-S3 Mini |
| USB Port | USB-C | USB-C |
| Digital I/O Pins | 14 | 14 |
| Analog input pins | 6(14-bit) | 6(14-bit) |
| DAC | 1(12-bit) | 1(12-bit) |
| PWM pins | 6(12-bit) | 6(12-bit) |
| CAN Bus | 1 | 1 |
| Input voltage (VIN) | 6-24 V | 6-24 V |
| Memory | 256 kB Flash, 32 kB RAM | 256 kB Flash, 32 kB RAM ESP: 384 kB ROM, 512 kB SRAM |
| Clock speed | 48 MHz | 48 MHz ESP: 240 MHz |
| Dimensions | 68.58 x 53.44 mm | 68.58 x 53.44 mm |
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
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
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:
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).
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:
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.
