Hacking an Arduino ISP Shield for AtTiny45 / AtTiny85

This is how to hack an Evil Mad Scientists Lab Arduino ISP Shield so that you can use the Arduino environment to program some nifty little microcontrollers.


The Arduino is a great little development environment for creating electronic projects http://www.arduino.cc/ but there are times when you just want the minimum possible pieces, and don't want the expense, or size, of a full Arduino plus breadboard/prototyping shield.

That's when you want to use a dinky microcontroller.

Fortunately AtMel (who make the AtMega inside the Arduino) also make a bunch of little ones called AtTiny. These range from 6 pin to 28 pin chips, and use almost the same instruction set as the big guys - they are part of the same AVR family.

My chip of choice for these kinds of projects is the ATtiny85

It has 8K of program memory, comes in a PDIP 8 pin package and has 5 (or 6) I/O pins. It also has 512 bytes of static RAM, and 512 bytes of EEPROM. It can run on two AA batteries (3 Volts, some version will go as low a 1.8V), and doesn't use much power.

For the technically inclined see http://www.atmel.com/dyn/resources/prod_documents/2586S.pdf for a summary of its capabilities.

Step 1 Things you will need

Arduino http://arduino.cc/en/Main/Hardware

- for this instructable an older Arduino is better than the latest.  The UNO has a problem, soon to be resolved, which prevents it from working as an ISP.    I use a Diecimila with an older atMega168 - this is a good use of an older device.

- if you don't already have one, I can recommend Adafruit http://www.adafruit.com/ as a supplier


Arduino ISP Shield http://evilmadscience.com/productsmenu/tinykitlist/253

- this image is from EMSL website
- build the ISP kit, and make sure it works.
- you most likely will want the jumper connection set to

    OVERRIDE AUTORESET - YES PLEASE

- also load the Arduino ISP example sketch  Files -> Examples -> ArduinoISP and upload it into your Arduino.


Software follow the instructions here: http://hlt.media.mit.edu/wiki/pmwiki.php?n=Main.ArduinoATtiny4585

- this is a really nice page with good information about how you can wire up your own breadboard to achieve the same thing.
- in particular you will need to install the AtTiny45_85 support files http://hlt.media.mit.edu/wiki/uploads/Main/attiny45_85.zip


Microcontrollers

- AtTiny45 or AtTiny85 chips to program - they are available from Mouser, DigiKey and many other places.


Miscellaneous

- connecting wire - I used bits of wire wrap because it is small and neat; but any insulated wire, you can solder, will do!