Programming an ATtiny85 with Arduino

I am currently working on this LED bar and I ran into, let's say a problem. Up here I want to use my WS2801 LED strip to play some different animations which I want to cycle through with a push button.

This project requires a separate microcontroller for the LED strip, which will be an ATtiny85. The ATtiny85 is a smaller and more affordable option compared to the Arduino Uno's ATmega 328.

Why Choose ATtiny85?

• Cost-effective (around $1)
• 5 IOs, sufficient for this project
• 8 kilobytes of flash memory, enough space for some animations

Software Requirements

To program the ATtiny85 using Arduino software and an Arduino Uno as a programmer, you need to:

1. Download and install Arduino software (version 1.0.5)
2. Download board data for the ATtiny from HiloTech.org
3. Extract the zip archive and copy the ATtiny folder into the Arduino hardware folder

Hardware Requirements

• ATtiny85 IC
• Arduino Uno (as a programmer)
• 10uF capacitor
• Jumper wires

Wiring the ATtiny85

Connect the Arduino pins to the ATtiny85 IC as follows:

1. Arduino pin 13 to ATtiny IO 2
2. Arduino pin 12 to ATtiny IO 1
3. Arduino pin 11 to ATtiny IO 0
4. Arduino pin 10 to ATtiny reset pin 1
5. 5V from Arduino to ATtiny VCC (pin 8)
6. Ground from Arduino to ATtiny ground (pin 4)

Programming the ATtiny85

Select the Arduino ISP as programmer and ATtiny85 with a clock of 1MHz as the board. Upload your sketch to the ATtiny85.

Example Sketch: Blinking LED

A simple blink sketch for an LED on IO 3 of the ATtiny85:

// Define the LED pin
const int ledPin = 3;

void setup() {
  pinMode(ledPin, OUTPUT);
}

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

ATtiny Programming Shield

Create a programming shield using a PCB and male headers. Connect the Arduino pins to the ATtiny85 IC using bridge wires.

Bitbanging SPI Protocol

Use bitbanging to emulate the SPI protocol, necessary for the WS2801 LED strip.

Conclusion

This project demonstrates how to program an ATtiny85 using Arduino software and an Arduino Uno as a programmer. The ATtiny85 is a cost-effective option for small projects, and bitbanging can be used to emulate the SPI protocol.

Programming ATtiny85 with Arduino Software

• ATtiny85 microcontroller
• Arduino Uno or other compatible board
• Breadboard and jumper wires
• USB cable for programming

1. Connect the Arduino Uno to your computer via USB.
2. Open the Arduino IDE and select "Tools" > "Board" > "Arduino Uno".
3. Select "Tools" > "Processor" > "ATtiny85".

1. Connect the ATtiny85 to the breadboard.
2. Connect the VCC pin of the ATtiny85 to the 5V pin on the Arduino Uno.
3. Connect the GND pin of the ATtiny85 to the GND pin on the Arduino Uno.
4. Select "Tools" > "Burn Bootloader".

1. Create a new sketch in the Arduino IDE.
2. Select "Tools" > "Board" > "ATtiny85".
3. Select "Sketch" > "Upload Using Programmer".

• Use an external crystal oscillator for more accurate timing.
• Use a voltage regulator to supply power to the ATtiny85.
• Use a programmer such as the USBasp or AVR ISP MKII for more reliable programming.

• ATtiny85 microcontroller
• Arduino IDE (version 1.6.x or later)
• USBasp or other AVR programmer (optional)
• Breadboard and jumper wires for prototyping (optional)

• Arduino IDE (version 1.6.x or later) with ATtiny85 support
• Avrdude (version 5.10 or later) for programming the ATtiny85
• Optional: Arduino Core for ATtiny85 (for more advanced features)

1. Open the Arduino IDE and go to Tools > Board > Boards Manager...
2. Search for "ATtiny" and install the "ATTinyCore" by David A. Mellis
3. Select the ATtiny85 from the "Tools > Board" menu

1. Open the Arduino IDE and go to Tools > Programmer > USBasp (or other AVR programmer)
2. Select the correct baud rate for your programmer (e.g., 9600)

1. Create a new sketch in the Arduino IDE or open an existing one
2. Verify the sketch by clicking on the "Verify" button or pressing Ctrl+R (Windows) or Cmd+R (Mac)
3. Upload the sketch to the ATtiny85 by clicking on the "Upload" button or pressing Ctrl+U (Windows) or Cmd+U (Mac)

• In your sketch, include the SoftwareSerial.h library: #include
• Create a SoftwareSerial object and define the RX and TX pins: SoftwareSerial mySerial(0, 1); // or other available pins

1. Digital I/O: Use the pinMode(), digitalRead(), and digitalWrite() functions
2. Analog I/O: Use the analogRead() function (only available on pins 2, 3, and 4)