How to Use SparkFun Pro Micro: Examples, Pinouts, and Specs

The SparkFun Pro Micro is a compact microcontroller board based on the ATmega32U4, a member of the AVR family of microcontrollers. It is designed for use in projects where space is at a premium, offering the functionality of the larger Arduino Leonardo in a smaller form factor. The Pro Micro is notable for its on-board USB connectivity, which allows it to emulate a mouse, keyboard, or other USB device, making it a popular choice for HID projects.

• Wearable electronics
• USB Human Interface Device (HID) projects
• Compact embedded systems
• Prototyping IoT devices
• Robotics

• Microcontroller: ATmega32U4
• Operating Voltage: 5V or 3.3V (depending on the model)
• Input Voltage: 4-9V (5V model) or 3.3-12V (3.3V model)
• Digital I/O Pins: 12 (of which 5 can be used as PWM outputs)
• Analog Input Pins: 4
• Clock Speed: 16 MHz (5V model) or 8 MHz (3.3V model)
• Flash Memory: 32 KB (ATmega32U4) of which 4 KB used by bootloader
• SRAM: 2.5 KB (ATmega32U4)
• EEPROM: 1 KB (ATmega32U4)
• USB Connectivity: Built-in micro USB port for programming and serial communication

1. Powering the Pro Micro: Connect the VCC pin to a 5V or 3.3V power supply, depending on the model of your Pro Micro. Ensure that the power supply is within the input voltage range specified for your model.

2. Programming the Pro Micro: Connect the board to your computer using a micro USB cable. The Pro Micro can be programmed using the Arduino IDE. Select "Arduino Leonardo" as the board type, as the Pro Micro shares the same microcontroller.

3. Connecting I/O Pins: Use the digital and analog pins to connect sensors, actuators, and other components. Remember to configure the pins correctly in your code.

4. Using USB Functionality: To use the Pro Micro's USB capabilities, include the appropriate libraries in your Arduino sketch, such as Keyboard.h or Mouse.h.

• Always ensure that the power supply voltage matches the requirements of the Pro Micro model you are using.
• When using the USB functionality, be aware that the Pro Micro will register as a USB device on the connected computer.
• Avoid connecting high-current loads directly to the I/O pins to prevent damage to the microcontroller.
• Use a current-limiting resistor when connecting LEDs to the I/O pins.

• Pro Micro not recognized by computer: Ensure that the micro USB cable is properly connected and that the cable supports data transfer, not just charging.
• Sketch upload fails: Double-check the board and port selections in the Arduino IDE. Press the reset button on the Pro Micro twice quickly to enter bootloader mode if necessary.
• I/O pin not functioning: Verify that the pin is configured correctly in your sketch and that there are no shorts or open circuits in your connections.

• If the Pro Micro is not recognized, try using a different USB port or cable.
• Ensure that the correct drivers are installed for the Pro Micro on your computer.
• Use serial print statements to debug your code and verify that the program is running as expected.

Here is a simple example of how to blink an LED connected to pin 9 (D9) on the SparkFun Pro Micro:

// Define the LED pin
const int ledPin = 9;

void setup() {
  // Set the LED pin as an output
  pinMode(ledPin, OUTPUT);
}

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

Remember to adjust the ledPin variable if you connect your LED to a different pin. This code will toggle the LED on and off every second, creating a blinking effect.