The ATTiny85 is a compact, high-performance 8-bit RISC-based microcontroller that packs a surprising amount of power into a tiny 8-pin package. It is the ideal choice for projects where space is at a premium and power consumption must be kept to an absolute minimum. Despite its small size, it features 8KB of flash memory, 512B of EEPROM, and 512B of SRAM. It is widely loved by the maker community for “shrinking” Arduino projects, as it can be programmed using the Arduino IDE. Whether you are building wearable electronics, small sensor nodes, or simple handheld gadgets, the ATTiny85 provides the perfect balance of simplicity and functionality.
ATTiny85 Pinout (DIP-8)
The ATTiny85 is most commonly used in the 8-pin Dual In-line Package (DIP), making it incredibly easy to use on breadboards or in small sockets.
| Pin Number | Pin Name | Description |
| 1 | PB5 (RESET) | Reset Pin / ADC1 / PCINT5 |
| 2 | PB3 (XTAL1) | Port B Pin 3 / Crystal Input / ADC3 |
| 3 | PB4 (XTAL2) | Port B Pin 4 / Crystal Output / ADC2 |
| 4 | GND | Ground |
| 5 | PB0 (MOSI) | Port B Pin 0 / SPI MOSI / PWM / SDA |
| 6 | PB1 (MISO) | Port B Pin 1 / SPI MISO / PWM |
| 7 | PB2 (SCK) | Port B Pin 2 / SPI Clock / ADC1 / SCL |
| 8 | VCC | Supply Voltage (1.8V – 5.5V) |
Technical Specifications – maximum
- Operating Voltage: 1.8V to 5.5V
- Flash Memory: 8 KB
- SRAM: 512 Bytes
- EEPROM: 512 Bytes
- Clock Speed: 0 to 20 MHz (Internal 8MHz oscillator available)
- DC Current per I/O Pin: 40.0 mA
- Operating Temperature: -40°C to +85°C
- Low Power Consumption: 0.15mA at 1.8V (Active Mode)
- ADC: 10-bit resolution, 4 channels
- PWM Channels: 2 (up to 4 using high-speed timer)
Key Features & Benefits
- Ultra-Compact Form Factor: The 8-pin design is perfect for space-constrained applications where a full Arduino is too bulky.
- Internal Oscillator: Eliminates the need for an external crystal in many projects, further reducing the component count.
- Universal Serial Interface (USI): Flexible hardware support for SPI and I2C (TWI) communication.
- Multiple Sleep Modes: Features Idle, ADC Noise Reduction, and Power-down modes to extend battery life in portable devices.
- High-Speed Timer: Includes a unique high-speed 64MHz PLL timer for high-frequency PWM generation.
Common Applications
- Wearable Electronics: Controlling LEDs or vibration motors in clothing and jewelry.
- Sensor Nodes: Reading analog sensor data and transmitting it via low-power wireless modules.
- USB Dongles: Using software-based USB (Digispark style) for HID devices like keyboards or mice.
- Battery Monitors: Monitoring voltage levels in Li-Po batteries and providing visual alerts.
- Signal Converters: Acting as a small logic gate replacement or signal inverter in larger circuits.
ATTiny85 Equivalent & Substitutes
- Selection Guide: Ultimate Microcontroller Selection Guide
- ATTiny45: Identical features but with 4KB of flash memory.
- ATTiny25: Identical features but with 2KB of flash memory.
- ATTiny13A: Even more basic 8-pin MCU with 1KB flash (very low cost).
- ATTiny84: A 14-pin version if you need 12 I/O pins instead of 6.
Related Tutorials on ElxHub – with links
- How to Program ATTiny85 using Arduino Uno
- Creating a Digispark-like USB Device with ATTiny85
- Power Saving Tips: ATTiny85 Deep Sleep Mode
- Driving an OLED Display with ATTiny85 via I2C
Conclusion
The ATTiny85 proves that great things come in small packages. It is the definitive choice for engineers and hobbyists who want to keep their designs elegant, cheap, and power-efficient. While it lacks the high pin count of its larger cousins, its ability to handle complex tasks like I2C communication and high-speed PWM makes it a versatile tool in any electronics toolkit. For anyone looking to take their project from a bulky prototype to a finished, compact product, the ATTiny85 is an essential microcontroller to master.
Download the Microcontroller’s Datasheet pdf
focus keyword: ATTiny85 Datasheet seo title: ATTiny85 Pinout, Specs, and Programming Guide | ElxHub slug: attiny85-microcontroller-datasheet meta description: Discover the ATTiny85 datasheet. Detailed 8-pin DIP pinout, 8KB flash specs, and low-power features. Learn why this tiny MCU is a maker favorite.