ATTINY85 - the Smallest Arduino




Introduction: ATTINY85 - the Smallest Arduino

This is one of the smallest if not the smallest arduino.

It has 6 Digital I/Os

Pin outs:

All pins can be used as Digital I/O

Pin 0 → I2C SDA, PWM (LED on Model B)
Pin 1 → PWM (LED on Model A)
Pin 2 → I2C SCK, Analog
Pin 3 → Analog In (also used for USB+ when USB is in use)
Pin 4 → PWM, Analog (also used for USB- when USB is in use)
Pin 5 → Analog In

I had some problems to make my PC associate with the USB driver. In fact the ArduinoISP was still unrecognized, but the Arduino IDE still uploaded the sketch. I had to download different drivers. Below I will post a link of some useful sites.

Another thing to say is that this does not work like an arduino when connected to a USB, even the upload is different.
Having said this, one can use the arduino IDE to upload the software.
One needs to compile to check the program for errors. Then hit the UPLOAD button with the ATTINY85 DISCONNECTED. In the bottom window, it will tell you when to plug the ATTINY85. Then it should upload.

Use the Example of the Blink, but instead use PIN 1, as this is where the on board LED is connected to.

My Arduino IDE is 1.6.5 on Windows XP.

Some helpful links

Got one of the drivers from here >

More info from the supplier

Links were active on 1st October 2015.

Be the First to Share


    • CNC and 3D Printing Contest

      CNC and 3D Printing Contest
    • Puzzles Challenge

      Puzzles Challenge
    • Lamps Challenge

      Lamps Challenge



    7 years ago

    I'm a complete noob currently (but I ordered a kit & a bunch of other parts; will be starting next week :) ) & have a few ATTINY85-related questions.

    ATTINY85 appears to refer to both the microcontroller and the development board that has the microcontroller on it, but the development board is cheaper than just the microcontroller on ebay (by over 50 cents) - why is this? Other than bulk, is there any advantage of the microcontroller over the development board? microcontroller, $2.49 USD shipped development board, $1.89 USD shipped development board, $1.90 USD shipped

    If I try to follow a project (like, say, this one for example: ), could I use the development board instead? Other than size, is there a reason not to? I'll be using 64bit Windows 7, if it makes a difference.

    Thanks in advance, apologies if I got lingo wrong, hopefully you understood me :)


    Reply 7 years ago

    From your links, the first one has a different packages (case).

    Here you can find further information of different types


    However, it depends on what you want to do with it. If you want to integrate it with your current pcb, you need to go to the first link, but if not, you can go on the others.

    It should works irrespective of the OS.

    If you want to go to option 1, do not forget to have a way to connect it to the USB, which is not so clear in the instructable document until you find out :-)

    Good luck on your project.