How to Use ATtiny85 20PU: Examples, Pinouts, and Specs

The ATtiny85 20PU is a small, low-power 8-bit microcontroller from the AVR family, designed for compact and efficient embedded applications. It features 8 KB of flash memory, 512 bytes of SRAM, and 6 general-purpose I/O pins. Despite its small size, the ATtiny85 is highly versatile and capable of handling a variety of tasks, making it ideal for simple control systems, IoT devices, wearable electronics, and other space-constrained projects.

• LED control and lighting systems
• Small IoT devices and sensors
• Wearable electronics
• Battery-powered devices
• Simple robotics and automation tasks
• Signal processing and data logging

The ATtiny85 20PU is a DIP-8 (Dual Inline Package) microcontroller with the following key specifications:

The ATtiny85 20PU has 8 pins, with the following configuration:

1. Power Supply: Connect the VCC pin to a regulated power source (2.7V to 5.5V) and the GND pin to ground.
2. Programming: Use an ISP (In-System Programmer) such as an Arduino UNO or a dedicated USB programmer to upload code to the ATtiny85.
3. I/O Connections: Connect peripherals (e.g., LEDs, sensors, or buttons) to the I/O pins (PB0 to PB5) as needed.
4. Clock Source: The ATtiny85 can use its internal 8 MHz oscillator or an external clock source. Configure this in the fuse settings during programming.

• Pull-Up Resistors: Enable internal pull-up resistors for input pins if no external pull-up is used.
• Power Consumption: Use sleep modes to reduce power consumption in battery-powered applications.
• Pin Limitations: Avoid exceeding the maximum current rating of 40 mA per pin or 200 mA for the entire chip.
• Decoupling Capacitor: Place a 0.1 µF ceramic capacitor between VCC and GND to stabilize the power supply.

Below is an example of how to blink an LED connected to PB0 using the Arduino IDE:

// Include the necessary library for ATtiny85
// Ensure you have installed the ATtiny board package in Arduino IDE
void setup() {
  pinMode(0, OUTPUT); // Set PB0 (pin 5) as an output pin
}

void loop() {
  digitalWrite(0, HIGH); // Turn the LED on
  delay(1000);           // Wait for 1 second
  digitalWrite(0, LOW);  // Turn the LED off
  delay(1000);           // Wait for 1 second
}

Steps to Upload Code:

1. Install the ATtiny board package in the Arduino IDE.
2. Connect the ATtiny85 to the Arduino UNO as an ISP programmer:
   • Arduino UNO Pin 10 → ATtiny85 RESET
   • Arduino UNO Pin 11 → ATtiny85 PB0 (MOSI)
   • Arduino UNO Pin 12 → ATtiny85 PB1 (MISO)
   • Arduino UNO Pin 13 → ATtiny85 PB2 (SCK)
   • Arduino UNO GND → ATtiny85 GND
   • Arduino UNO 5V → ATtiny85 VCC
3. Select "ATtiny85" as the board and "8 MHz (Internal)" as the clock in the Arduino IDE.
4. Upload the code using "Upload Using Programmer."

1. Problem: The ATtiny85 is not responding or programming fails.

   • Solution: Check the wiring between the programmer and the ATtiny85. Ensure the RESET pin is correctly connected.
   • Solution: Verify that the correct board and clock settings are selected in the Arduino IDE.

2. Problem: The LED does not blink as expected.

   • Solution: Double-check the pin number in the code. For example, PB0 corresponds to pin 0 in the Arduino IDE.
   • Solution: Ensure the LED is connected with the correct polarity and has a current-limiting resistor (e.g., 220 Ω).

3. Problem: Excessive power consumption in battery-powered applications.

   • Solution: Use sleep modes and disable unused peripherals in the code to reduce power usage.

• Q: Can I use the ATtiny85 without an external clock?
  A: Yes, the ATtiny85 has an internal 8 MHz oscillator, which is sufficient for most applications.

• Q: How do I reset the ATtiny85 fuse settings?
  A: Use an ISP programmer to reprogram the fuses. Be cautious when setting the clock source to avoid locking the chip.

• Q: Can I use the ATtiny85 for I2C communication?
  A: Yes, the ATtiny85 supports I2C communication using software libraries like TinyWire.

By following this documentation, you can effectively integrate the ATtiny85 20PU into your projects and troubleshoot common issues.