How to Use ATtiny85: Examples, Pinouts, and Specs

Introduction

The ATtiny85 is a compact, high-performance microcontroller from Microchip Technology, designed for use in a variety of applications due to its small size and low power consumption. Based on the AVR RISC architecture, it features 8KB of in-system programmable flash memory, making it ideal for simple embedded projects, such as DIY electronics, wearables, and IoT devices.

Explore Projects Built with ATtiny85

ATtiny85 and OLED Display Based Interactive Game with Buzzer and LED

This circuit is a simple interactive game system powered by a 5V battery, featuring an ATtiny85 microcontroller, an OLED display, a buzzer, an LED, and multiple pushbuttons. The OLED displays a menu with options to start a game, which is controlled by the ATtiny85. The buzzer and LED provide audio-visual feedback, and the pushbuttons are used for user input to navigate the menu and play the game.

Open Project in Cirkit Designer

ATtiny-Controlled LED Blinker Circuit

This circuit consists of an ATtiny microcontroller that controls an LED through one of its GPIO pins (PB4). A resistor is connected in series with the LED to limit the current. The ATtiny is powered by a 3.3V battery, and the LED is designed to turn on when the ATtiny is powered up.

Open Project in Cirkit Designer

ATmega328P-Based Sensor Hub with OLED Display and LIDAR

This circuit features an Mtiny Uno ATmega328P microcontroller as its central processing unit, interfacing with a variety of sensors and peripherals. It includes a 0.96" OLED display and an MPU6050 accelerometer/gyroscope for user interface and motion sensing, respectively. The circuit also integrates a TF LUNA LIDAR for distance measurement, a DHT11 sensor for temperature and humidity readings, and uses a 9V battery with a 7805 voltage regulator for power management. Communication with a computer for programming and data exchange is facilitated by an Adafruit FTDI Friend module.

Open Project in Cirkit Designer

ATMEGA328 Battery-Powered LED Blinker with FTDI Programming

This circuit is a basic microcontroller setup using an ATMEGA328, powered by a 5V battery, and includes an FTDI programmer for serial communication. It features a pushbutton for reset functionality and two LEDs controlled by the microcontroller, with one LED blinking at a 1-second interval as programmed.

Open Project in Cirkit Designer

Common Applications and Use Cases

Hobbyist electronics projects
Wearable devices
Simple IoT applications
Prototyping and educational purposes
Battery-operated devices

Technical Specifications

Key Technical Details

Flash Memory: 8KB
SRAM: 512 Bytes
EEPROM: 512 Bytes
I/O Pins: 6
PWM Channels: 4
ADC Channels: 4 (10-bit resolution)
Clock Speed: Up to 20 MHz
Operating Voltage: 2.7V - 5.5V
Temperature Range: -40°C to +85°C

Pin Configuration and Descriptions

Pin Number	Name	Description
1	PB5	Reset and programming interface, also serves as I/O pin
2	PB3	Analog input or digital I/O, ADC3
3	PB4	Analog input or digital I/O, ADC2
4	GND	Ground pin
5	PB0	Digital I/O, OC0A (PWM output)
6	PB1	Digital I/O, OC0B (PWM output), ADC1
7	PB2	Digital I/O, INT0 (external interrupt), ADC0
8	VCC	Positive supply voltage

Usage Instructions

How to Use the ATtiny85 in a Circuit

Powering the ATtiny85:
- Connect the VCC pin to a power supply within the operating voltage range (2.7V - 5.5V).
- Connect the GND pin to the ground of the power supply.
Programming the ATtiny85:
- Use an AVR programmer or an Arduino as an ISP (In-System Programmer) to upload code to the ATtiny85.
- Ensure the correct pin mapping is used when programming the ATtiny85 with an Arduino.
Connecting I/O Pins:
- Configure the I/O pins as input or output according to your application needs.
- Use the PWM pins for analog output applications like dimming LEDs or controlling motor speed.
Using ADC Channels:
- Connect analog sensors to ADC pins for analog-to-digital conversion.
- Ensure proper reference voltage is set in your code for accurate readings.

Important Considerations and Best Practices

Always check the pinout and datasheet before connecting the ATtiny85 to other components.
Avoid supplying voltage higher than the maximum rating to prevent damage.
Use decoupling capacitors close to the VCC and GND pins to stabilize the power supply.
Consider using an external clock source for applications requiring precise timing.

Troubleshooting and FAQs

Common Issues

ATtiny85 not responding to programming:
- Check connections to the programmer.
- Ensure that the correct device is selected in the programming software.
- Verify that the ATtiny85 has not been set to use an external clock source without one being present.
Incorrect behavior in I/O operations:
- Double-check the pin configuration in your code.
- Ensure that the power supply is stable and within the specified range.

Solutions and Tips for Troubleshooting

If the ATtiny85 is unresponsive, try using a high-voltage programming mode if available.
For analog readings, calibrate the ADC regularly to maintain accuracy.
Use a multimeter to verify voltage levels and continuity in your circuit.

FAQs

Can the ATtiny85 be used with Arduino IDE?
- Yes, with the addition of the appropriate board package, the ATtiny85 can be programmed using the Arduino IDE.
What is the maximum current per I/O pin?
- The maximum DC current per I/O pin is 40 mA.
How can I reduce power consumption for battery-operated devices?
- Utilize sleep modes and disable unused peripherals to conserve power.

Example Code for Arduino UNO as ISP

#include <avr/sleep.h>
#include <avr/power.h>

void setup() {
  // Set up code here
}

void loop() {
  // Main code here

  // Example: Entering sleep mode to save power
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);
  sleep_enable();
  power_all_disable(); // Disable all peripherals
  sleep_mode();        // Enter sleep mode

  // The device will wake up here after an interrupt
  power_all_enable();  // Re-enable all peripherals
  sleep_disable();
}

Note: This example demonstrates how to put the ATtiny85 into a power-down sleep mode to conserve energy, which is useful for battery-operated devices. The actual implementation will vary based on the specific application and the required wake-up sources.