How to Use A-Star 32U4 Mini SV: Examples, Pinouts, and Specs

The A-Star 32U4 Mini SV is a compact and versatile microcontroller board developed by Pololu. It is based on the ATmega32U4 microcontroller, which features built-in USB functionality, making it ideal for projects requiring USB communication. The board includes 32KB of flash memory, 2.5KB of SRAM, and 1KB of EEPROM, providing ample resources for a wide range of applications. Its small form factor and robust design make it suitable for embedded systems, robotics, and IoT projects.

• Robotics and motor control
• IoT devices and home automation
• Sensor data acquisition and processing
• USB-based projects (e.g., HID devices, serial communication)
• Prototyping and educational purposes

• Microcontroller: ATmega32U4
• Operating Voltage: 5V
• Input Voltage Range: 5.5V to 36V
• Flash Memory: 32KB (4KB used by bootloader)
• SRAM: 2.5KB
• EEPROM: 1KB
• Clock Speed: 16 MHz
• USB Interface: Full-speed USB (12 Mbps)
• I/O Pins: 26 (7 can be used as PWM outputs, 12 as analog inputs)
• Dimensions: 1.9" × 0.7" (48 mm × 18 mm)
• Weight: 2.5 g

The A-Star 32U4 Mini SV has 26 I/O pins, which are broken out into two rows of through-hole pins. Below is a table describing the pin functions:

1. Powering the Board:

   • Connect a power source to the VIN pin (5.5V–36V) or via the USB port. The onboard regulator will provide a stable 5V to the microcontroller.
   • Ensure the input voltage does not exceed the specified range to avoid damaging the board.

2. Programming the Board:

   • The A-Star 32U4 Mini SV can be programmed using the Arduino IDE. Select "Arduino Leonardo" as the board type since it uses the same ATmega32U4 microcontroller.
   • Connect the board to your computer via a USB cable. The USB interface also provides serial communication.

3. Connecting Peripherals:

   • Use the digital and analog pins to interface with sensors, actuators, and other components.
   • For I2C communication, connect your device to the SDA and SCL pins. For UART communication, use the TX and RX pins.

4. Using PWM Outputs:

   • The PWM-capable pins (D3, D5, D6, D9, D10, D11, D13) can be used to control devices like LEDs or motors.

• Avoid exceeding the maximum input voltage of 36V to prevent damage to the onboard voltage regulator.
• Use decoupling capacitors when connecting sensors or other components to reduce noise and improve stability.
• When using the board in a breadboard, ensure proper alignment of the pins to avoid short circuits.

Below is an example code to blink an LED connected to pin D13:

// Blink an LED connected to pin D13 on the A-Star 32U4 Mini SV

void setup() {
  pinMode(13, OUTPUT); // Set pin D13 as an output
}

void loop() {
  digitalWrite(13, HIGH); // Turn the LED on
  delay(1000);            // Wait for 1 second
  digitalWrite(13, LOW);  // Turn the LED off
  delay(1000);            // Wait for 1 second
}

1. The board is not recognized by the computer:

   • Ensure the USB cable is properly connected and is a data cable (not a charge-only cable).
   • Check if the correct drivers are installed. Pololu provides drivers for Windows, which can be downloaded from their website.

2. Unable to upload code to the board:

   • Verify that "Arduino Leonardo" is selected as the board type in the Arduino IDE.
   • Double-tap the reset button to enter the bootloader mode and try uploading the code again.

3. The board overheats:

   • Check the input voltage to ensure it is within the 5.5V–36V range.
   • Ensure there are no short circuits in your circuit connections.

4. PWM outputs are not working:

   • Confirm that you are using the correct pins (D3, D5, D6, D9, D10, D11, D13) for PWM.
   • Ensure the analogWrite() function is used correctly in your code.

Q: Can the A-Star 32U4 Mini SV be powered solely via USB?
A: Yes, the board can be powered through the USB port, which provides 5V to the microcontroller.

Q: Is the A-Star 32U4 Mini SV compatible with Arduino libraries?
A: Yes, it is fully compatible with most Arduino libraries, as it uses the ATmega32U4 microcontroller.

Q: What is the maximum current output of the 5V pin?
A: The 5V pin can supply up to 1A, depending on the input voltage and the power dissipation of the onboard regulator.

Q: Can I use the board for battery-powered applications?
A: Yes, the wide input voltage range (5.5V–36V) makes it suitable for battery-powered projects.