How to Use ATTINY84A: Examples, Pinouts, and Specs

The ATTINY84A is a low-power 8-bit microcontroller from Atmel's AVR family, designed for compact and efficient embedded applications. With its 14-pin configuration, 8KB of flash memory, and versatile peripherals, the ATTINY84A is ideal for projects requiring a small footprint and low power consumption. It supports a wide range of functionalities, including timers, analog-to-digital conversion (ADC), and pulse-width modulation (PWM).

• IoT devices and sensors
• Wearable electronics
• Small robotics and automation systems
• Battery-powered devices
• LED control and lighting systems

The ATTINY84A has 14 pins, each with specific functions. Below is the pinout description:

1. Power Supply: Connect the VCC pin to a power source (1.8V to 5.5V) and the GND pin to ground.
2. Programming: Use an AVR programmer or an Arduino as an ISP (In-System Programmer) to upload code to the ATTINY84A.
3. I/O Configuration: Configure the I/O pins as digital or analog inputs/outputs in your code.
4. Peripherals: Utilize the built-in peripherals such as ADC, timers, and PWM for your application.
5. Communication: Use SPI, I²C, or USART for interfacing with other devices.

• Decoupling Capacitors: Place a 0.1µF capacitor between VCC and GND to stabilize the power supply.
• Clock Source: The ATTINY84A can use an internal 8 MHz oscillator or an external crystal oscillator for higher precision.
• Pull-Up Resistors: Enable internal pull-up resistors for unused input pins to prevent floating states.
• Low Power Modes: Use sleep modes to reduce power consumption in battery-powered applications.

Below is an example of programming the ATTINY84A using an Arduino UNO as an ISP:

1. Connect the Arduino UNO to your computer and upload the "ArduinoISP" sketch from the Arduino IDE.
2. Wire the ATTINY84A to the Arduino UNO as follows:
   • ATTINY84A Pin 1 (VCC) → Arduino 5V
   • ATTINY84A Pin 14 (GND) → Arduino GND
   • ATTINY84A Pin 4 (PB2) → Arduino Pin 10 (SS)
   • ATTINY84A Pin 7 (PA6) → Arduino Pin 11 (MOSI)
   • ATTINY84A Pin 8 (PA4) → Arduino Pin 12 (MISO)
   • ATTINY84A Pin 9 (PA3) → Arduino Pin 13 (SCK)

// Blink an LED connected to PB0 (Pin 2 on ATTINY84A)

// Define the LED pin
#define LED_PIN 0  // PB0 corresponds to digital pin 0 on ATTINY84A

void setup() {
  pinMode(LED_PIN, OUTPUT);  // Set PB0 as an output pin
}

void loop() {
  digitalWrite(LED_PIN, HIGH);  // Turn the LED on
  delay(500);                  // Wait for 500 milliseconds
  digitalWrite(LED_PIN, LOW);   // Turn the LED off
  delay(500);                  // Wait for 500 milliseconds
}

To upload the code:

1. Select "ATTINY84A" as the board in the Arduino IDE.
2. Choose the appropriate clock frequency (e.g., 8 MHz internal).
3. Select "Arduino as ISP" as the programmer.
4. Upload the sketch.

1. The ATTINY84A is not responding to programming commands.

   • Solution: Ensure the wiring between the programmer and the ATTINY84A is correct. Check for loose connections.
   • Tip: Verify that the correct board and clock settings are selected in the Arduino IDE.

2. The microcontroller is not running the uploaded code.

   • Solution: Check the power supply voltage and ensure it is within the operating range (1.8V to 5.5V).
   • Tip: Confirm that the fuses are set correctly for the desired clock source.

3. Analog readings are unstable.

   • Solution: Add a decoupling capacitor (e.g., 0.1µF) near the VCC and GND pins.
   • Tip: Use an external reference voltage for the ADC if higher precision is required.

4. PWM output is not working as expected.

   • Solution: Verify that the correct timer and pin are configured for PWM in the code.
   • Tip: Check the datasheet for the specific timer and pin mappings.

• Can the ATTINY84A run at 3.3V?

  • Yes, the ATTINY84A operates within a voltage range of 1.8V to 5.5V, making it compatible with 3.3V systems.

• What is the maximum clock speed of the ATTINY84A?

  • The maximum clock speed is 20 MHz when using an external crystal oscillator.

• How many PWM channels are available?

  • The ATTINY84A provides 4 PWM channels.

• Can I use the ATTINY84A for I²C communication?

  • Yes, the ATTINY84A supports I²C communication using the USI (Universal Serial Interface) module.

This concludes the documentation for the ATTINY84A. For further details, refer to the official datasheet provided by Atmel.