ATtiny85

The ATtiny85 is a small yet powerful 8-bit microcontroller from the AVR family, developed by Atmel (now owned by Microchip Technology). It is widely used in embedded systems due to its compact size, low power consumption, and affordability. Despite its small footprint, the ATtiny85 offers a robust set of features, making it ideal for various applications, including IoT devices, automation, and DIY electronics projects. This article explores the ATtiny85 microcontroller’s architecture, features, applications, programming, and example projects.

Features of ATtiny85

The ATtiny85 microcontroller is known for its simplicity and efficiency. Some of its key features include:

  • 8-bit AVR RISC Architecture: Ensures a compact and efficient instruction set.
  • 8 KB Flash Memory: Stores program code.
  • 512 Bytes SRAM: Provides memory for variable storage.
  • 512 Bytes EEPROM: Retains data even after power loss.
  • Up to 20 MHz Clock Speed: Supports external clock sources for enhanced performance.
  • 6 General-Purpose I/O Pins: Offers flexibility for digital input/output operations.
  • Analog-to-Digital Converter (ADC): 10-bit resolution with up to 4 channels.
  • Pulse Width Modulation (PWM): Supports up to 3 PWM channels.
  • Multiple Communication Interfaces: Supports SPI, I2C (TWI), and UART (software-based).
  • Low Power Consumption: Ideal for battery-powered applications.
  • Watchdog Timer: Ensures system stability by resetting during software failures.
  • Internal Oscillator: Eliminates the need for an external clock source in many applications.

ATtiny85 Architecture

The ATtiny85 follows the Harvard architecture, where program memory and data memory are separate, enabling efficient execution. Key architectural elements include:

  1. CPU Core:
    • 8-bit RISC processor with a streamlined instruction set.
    • Efficient execution with most instructions completing in a single clock cycle.
  2. Memory Organization:
    • Flash Memory (8 KB): Stores program code.
    • SRAM (512 Bytes): Temporary data storage for running programs.
    • EEPROM (512 Bytes): Stores non-volatile data.
  3. Timers and PWM:
    • One 8-bit timer/counter with compare modes.
    • Supports PWM for motor control and signal modulation.
  4. Interrupt System:
    • External and internal interrupts enhance system responsiveness.
  5. Peripheral Interfaces:
    • SPI and I2C (TWI) for communication with other devices.
    • Software-based UART for serial communication.

Development Tools for ATtiny85

To program the ATtiny85, specific hardware and software tools are required.

1. Hardware Requirements

  • ATtiny85 Standalone Chip or Development Board: Used for prototyping and deployment.
  • USB ASP Programmer or Arduino as ISP: Required for bootloading and programming.
  • Power Supply: Operates on 5V or a regulated 3.3V source.

2. Software Tools

  • Arduino IDE: Provides an easy-to-use environment for programming.
  • Atmel Studio: A professional-grade IDE for AVR microcontrollers.
  • AVR GCC Compiler: Open-source compiler for advanced programming.
  • AVRDUDE: Command-line tool for flashing firmware onto the microcontroller.

Getting Started with ATtiny85

To begin working with ATtiny85, follow these steps:

  1. Install the Arduino IDE (if using Arduino as an ISP programmer).
  2. Connect the ATtiny85 to the Programmer using an ISP connection.
  3. Select the ATtiny85 Board and Programmer in the Arduino IDE.
  4. Write and Compile Code in the Arduino IDE.
  5. Upload the Code to the ATtiny85.
  6. Test the Application.

Example Project: Blinking LED

A simple project to get started with ATtiny85 is blinking an LED.

Components Required:

  • ATtiny85 microcontroller.
  • LED.
  • Resistor (220Ω).
  • Breadboard and jumper wires.
  • USB ASP Programmer or Arduino as ISP.

Code Example (Using Arduino IDE):

void setup() {
    pinMode(0, OUTPUT); // Set pin 0 as an output
}

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

This program toggles an LED connected to pin 0 every second.

Applications of ATtiny85

Due to its compact size and versatility, the ATtiny85 is used in various industries and projects:

  1. Embedded Systems:
    • Small-scale automation and control applications.
  2. IoT and Smart Devices:
    • Low-power wireless sensor nodes.
    • Battery-powered remote control devices.
  3. Wearable Technology:
    • Smart rings, wristbands, and biofeedback devices.
  4. Home Automation:
    • Smart lighting and motion-activated devices.
  5. Consumer Electronics:
    • Digital thermometers and handheld gadgets.
  6. DIY Projects:
    • Compact robotics and electronic toys.

Advanced ATtiny85 Projects

1. Battery-Powered Temperature Logger

  • Uses an external temperature sensor to log temperature data.
  • Saves data to EEPROM for later retrieval.

2. Mini IR Remote Control

  • Uses infrared LEDs to control household appliances.
  • Ideal for TV remotes or smart home automation.

3. Capacitive Touch Sensor Interface

  • Converts a simple copper pad into a touch-sensitive button.
  • Used for interactive electronics projects.

4. Sound-Activated Light Switch

  • Uses a microphone module to toggle lights with a clap.
  • Enhances accessibility and convenience in smart homes.

Future of ATtiny85

While newer microcontrollers with more processing power exist, the ATtiny85 remains a popular choice due to its affordability, low power consumption, and ease of use. It continues to be widely used in hobbyist, educational, and commercial applications.

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