Tiniest arduino | Smallest arduino

Tiniest arduino | Smallest arduino

From website :
http://hlt.media.mit.edu/?p=1695


This tutorial shows you how to program an ATtiny45, ATtiny85, ATtiny44 or ATtiny84 microcontroller using the Arduino software (version 1.0.1). These are small, cheap ($2-3) microcontrollers that are convenient for running simple programs. The ATtiny45 and ATtiny85 have eight legs and are almost identical, except that the ATtiny85 has twice the memory of the ATtiny45 and can therefore hold more complex programs. The ATtiny44 and ATtiny84 have 14-legs and more inputs and outputs. Thanks to Mark Sproul for his work on making the Arduino core portable across processors.
Materials and Tools


For this tutorial, you’ll need:
An in-system programmer (ISP), a piece of hardware used to load programs onto the ATtiny. Options include:

A commercial programmer like the AVRISP mkII or USBtinyISP.
a Arduino Uno or Duemilanove (w/ an ATmega328, not an older board with an ATmega168). See this tutorial for using an Arduino board as a programmer
the TinyProgrammer, a board that we’ve developed to make it as easy as possible to program the ATtiny45 and 85.
ATtiny45 or ATtiny85 (8-pin DIP package) or an ATtiny44 or ATtiny84.
a solderless breadboard and jumper wires (unless you’re using the TinyProgrammer w/ the ATtiny45 or 85)


For more information, see our list of materials and parts and our list of prototyping supplies.
Software


You’ll need the Arduino software, version 1.0.1. (Instructions for Arduino 0022 are also available.) You can download Arduino 1.0.1 from the Arduino site. Installation instructions are available for Windows and for Mac OS X.


Download: Arduino 1.0.1 and the ATtiny zip (from this GitHub repository)
Installing ATtiny support in Arduino
Download: ATtiny (from this GitHub repository)
Locate your Arduino sketchbook folder (you can find its location in the preferences dialog in the Arduino software)
Create a new sub-folder called “hardware” in the sketchbook folder.
Copy the attiny folder from inside the .zip to the hardware folder. You should end up with folder structure like Documents > Arduino > hardware > attiny that contains the fileboards.txt and another folder called variants.
Restart the Arduino development environment.
You should see ATtiny entries in the Tools > Board menu.

Connecting the ATtiny


You’ll need to provide power to the ATtiny and connect it to your programmer. That is, connecting MISO, MOSI, SCK, RESET, VCC, and GND of the programmer to the corresponding pins on the ATtiny. (Or, if you’re using an circuit w/ an ATtiny, simply connect the programmer to the ISP header on the board – you may also need to power the board separately.)


Instructions and diagrams are available for:

Configuring the ATtiny to run at 8 MHz (for SoftwareSerial support)


By default, the ATtiny’s run at 1 MHz (the setting used by the unmodified “ATtiny45″, etc. board menu items). You need to do an extra step to configure the microcontroller to run at 8 MHz – necessary for use of the SoftwareSerial library. Once you have the microcontroller connected, select the appropriate item from the Boards menu (e.g. “ATtiny45 (8 MHz)”). Then, run the “Burn Bootloader” command from the Tools menu. This configures the fuse bits of the microcontroller so it runs at 8 MHz. Note that the fuse bits keep their value until you explicitly change them, so you’ll only need to do this step once for each microcontroller. (Note this doesn’t actually burn a bootloader onto the board; you’ll still need to upload new programs using an external programmer.)
Programming the ATtiny


Next, we can use the Arduino as an ISP to upload a program to the ATtiny:




Open the Blink sketch from the examples menu.

• Change the pin numbers from 13 to 0.
• Select the appropriate item from the Tools > Board menu (leave the serial port set to that of your Arduino board).
• Select the appropriate item from the Tools > Programmer menu (e.g. “Arduino as ISP” if you’re using an Arduino board as the programmer, USBtinyISP for the USBtinyISP, FabISP, or TinyProgrammer, etc).
• Upload the sketch.

You should see “Done uploading.” in the Arduino software and no error messages. If you then connect an LED between pin 0 and ground, you should see it blink on and off. Note that you may need to disconnect the LED before uploading a new program.
ATtiny Microcontroller Pin-Outs

Reference


The following Arduino commands should be supported:
pinMode()
digitalWrite()
digitalRead()
analogRead()
analogWrite()
shiftOut()
pulseIn()
millis()
micros()
delay()
delayMicroseconds()
SoftwareSerial (has been updated in Arduino 1.0)
References
arduino-tiny: alternative approach to ATtiny support for Arduino
TinyWireM & TinyWireS: Wire (I2C / TWI) library for the ATtiny85 (using USI)