Programming the ATTINY85 Chip




Introduction: Programming the ATTINY85 Chip

About: I like to make stuff from rockets to electronics.

How to make your Arduino projects Small and cheap? Simple program an ATTiny85 Chip!

Step 1: Parts List

We are going to need the following:

  • Some jumper wires
  • 1 x 10 micro farad capacitor
  • The ATTiny85 Chip
  • A breadboard and
  • An Arduino

For Extra visual's (that are not really required) I'm going to add:

  • 3 LED's
  • 1 x 330 Ohm Resistor
  • And some extra jumper cables

Step 2: Breadboard and Schematics

The circuit is sectioned into 2 parts

  • The Chip Programming section and
  • The LED's Section

Step 3: Setting Up the Arduino IDE

Before we start with the circuit build, Head over to the Arduino IDE

Open the Sketch ArduinoISP from the File, Examples and ArduinoISP menus

Verify and upload this sketch to your Arduino

The Arduino software does not natively support the ATTiny85 so we need to add support for it.

  • Open the Boards Manager from the Tools, Board Menus
  • Select the attiny from the list once the software has updated

Note that you will require an internet connection for the ATTINY board manager to download.

  • Search for attiny, either manually scrolling down the list or typing in "attiny" in the filter field.
  • Click Install the (Use the latest version).

Lets set up the program to use the arduino as a programmer.

Select Arduino as ISP from the Tools, Programmer Menus

Select ATTiny from the Tools, Board Menus

Select ATTINY85 from the Tools, Processor Menus

I'm selecting 16Mhz Internal from the Tools, Clock Menu

Step 4: Very Short Explanation of the ATTINY85 Pins

The chip has 8 pins, to program the ATTINY85 we are interested only 6 of them MISO, MOSI, SCK, RESET, Ground, and Positive.

If you look closely at the chip you will see a dot.

This is Pin 1. Pin 2 through 8 follow in an anti-clockwise order around the chip.

Conveniently the headers on the Arduino are easy to work with to program the ATTINY85.

We are ready to jump into building the programming circuit

Step 5: The Programming Circuit

We are ready to jump into building the programming circuit

  • Unplug your Arduino
  • Place the ATTiny Chip onto the breadboard
  • Connect the ground from the Arduino to the Ground Rail
  • Connect the 5V from the Arduino to pin 8 of the ATTiny.
  • Connect pin 4 of the chip to ground.
  • Place the Capacitor between ground and another terminal strip (The Anode of the capacitor must be connected to ground)
  • Connect the Cathode of the Capacitor to the Reset pin of the Arduino
  • Connect a lead from the header pin 10 of the Arduino to pin 1 of the chip
  • Connect Arduino Pin 11 to Pin 5 of the chip
  • Connect Arduino Pin 12 to Pin 6 of the chip and
  • Connect Arduino pin 13 to pin 7 of the ATTiny85

The programmer will now work but in the next step I'm going to add some LED's. (Because LED's are fun to have)

Step 6: Adding LED's

  • Connect the 330k resistor to ground and a terminal strip.
  • Connect Arduino pins 7, 8 and 9 to separate terminal strips.
  • Place LED's between each of the terminal strips (connected to 7, 8 and 9) and to the terminal strip with the 330k Resistor.

Step 7:

Head back over to the Arduino IDE

First we need to burn the Bootloader to the chip.

  • Select Burn Bootloader from the Tools Menu
  • Once that is done, you can upload Arduino Sketches to the Attiny chip as if it were an Arduino.

Just remember the limitations to the ATTINY chip and any program within the limitations will work.

1 Person Made This Project!


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11 months ago on Step 1

I was able to burn a simple blink formula but i get some weird errors. can you help.. Attaching the error screen shot. Thanks


Question 3 years ago on Step 7

Capasitor and led is wrong side, turn it around and the it is right. For every led's needed be own 330R resistor.


Answer 2 years ago

Good day, my Friend.

You're sooo right as for the LED's polarity, however, for the resistor(s), only one would be needed IF only ONE LED is on at a time. If not, you're right again, otherwise, intensity will drop if two are lit simultaneously, and even more if all three are on. But in this case, I think it was ment to be lit one at a time.

Have a great day !


5 years ago

Are you sure you put in the capacitor the right way? All others connect ground to ground and positive to the reset pin of Arduino.

Its not a good way to connect three LEDs to one limiting resitor on the ground pin. Better way is to put a seperate resistor to the positive side of each LED.


5 years ago

I can never get the wiring right. That is why I designed a shield:


5 years ago

I am having some issues trying to download the Instructable, Usually they will download as a PDF file, but this will only give the download option as text. Can you let me know what I have to do to dowload in PDF format. Thank you.


5 years ago

One question: does the programmer matter when burning a bootloader, because you have it set to AVR ISP...


Reply 5 years ago

Yes It does matter. It should be set to Arduino as ISP. Thanks for pointing that mistake out!


Reply 5 years ago

No problem thanks for making it clear


5 years ago

Can you run interupts on them?