How to Use PICAXE-08: Examples, Pinouts, and Specs

The PICAXE-08, manufactured by Revolution Education Ltd, is a low-cost microcontroller designed for educational and hobbyist projects. It features a simple programming interface and supports a BASIC-like programming language, making it highly accessible for beginners. Despite its simplicity, the PICAXE-08 is versatile and capable of controlling various electronic devices, making it suitable for a wide range of applications, from simple automation tasks to more complex robotics projects.

• Educational projects for learning microcontroller programming
• Simple automation systems (e.g., light control, motor control)
• Robotics and mechatronics
• Sensor-based projects (e.g., temperature, light, or motion sensing)
• Hobbyist electronics and DIY projects

The PICAXE-08 comes in an 8-pin Dual Inline Package (DIP). Below is the pinout and description:

1. Power Supply: Connect the VCC pin (Pin 1) to a 3V-5V power source and the GND pin (Pin 4) to ground.
2. Programming: Use the PICAXE Programming Editor software to write your program in the BASIC-like language. Connect the Serial In (Pin 7) and Serial Out (Pin 8) pins to a compatible programming cable for downloading the program.
3. Input/Output Configuration: Configure the I/O pins (Pins 2, 3, 5, and 6) in your program as either inputs or outputs, depending on your application.
4. Peripheral Connections: Connect sensors, LEDs, motors, or other peripherals to the I/O pins as needed.

• Power Supply: Ensure the power supply voltage is within the specified range (3V to 5V). Exceeding this range may damage the microcontroller.
• Programming Cable: Use the official PICAXE programming cable for reliable communication with the microcontroller.
• Pull-Down Resistors: For input pins, consider using pull-down resistors to prevent floating inputs.
• Current Limitations: Avoid exceeding the maximum current rating of the I/O pins. Use external transistors or relays for high-current loads.
• Decoupling Capacitor: Place a 0.1 µF decoupling capacitor between VCC and GND to reduce noise and improve stability.

Although the PICAXE-08 is a standalone microcontroller, it can communicate with an Arduino UNO via serial communication. Below is an example of how to send data from an Arduino UNO to the PICAXE-08:

Arduino UNO Code:

void setup() {
  Serial.begin(4800); // Set baud rate to 4800 for PICAXE communication
}

void loop() {
  Serial.println("Hello, PICAXE!"); // Send a message to the PICAXE-08
  delay(1000); // Wait for 1 second
}

PICAXE-08 Code:

main:
  serin 7, N4800, b0  ' Receive data on Serial In (Pin 7) at 4800 baud
  sertxd ("Received: ", b0, 13, 10) ' Send received data to Serial Out (Pin 8)
  pause 1000           ' Wait for 1 second
  goto main            ' Repeat the loop

1. The PICAXE-08 is not responding to programming commands.

   • Solution: Ensure the programming cable is properly connected to the Serial In (Pin 7) and Serial Out (Pin 8) pins. Verify that the correct COM port is selected in the PICAXE Programming Editor.

2. The microcontroller is not powering on.

   • Solution: Check the power supply voltage and connections. Ensure the VCC (Pin 1) and GND (Pin 4) pins are correctly connected.

3. Input pins are behaving erratically.

   • Solution: Use pull-down resistors on input pins to prevent floating inputs.

4. Output pins are not driving connected devices.

   • Solution: Verify that the connected device does not exceed the current rating of the output pins. Use external transistors or relays for high-current loads.

• Can the PICAXE-08 be powered by batteries? Yes, the PICAXE-08 is designed for low-power operation and can be powered by batteries (e.g., 3V coin cell or 4.5V AA battery pack).

• What programming software is required? The PICAXE Programming Editor, available for free from Revolution Education Ltd, is used to program the PICAXE-08.

• Can the PICAXE-08 handle analog inputs? Yes, the PICAXE-08 supports analog inputs on specific pins (e.g., Input 3 and Input 4).

• What is the maximum program size? The PICAXE-08 has 256 bytes of program memory, which is sufficient for small to medium-sized projects.

This concludes the documentation for the PICAXE-08 microcontroller.