Arduino Standalone 3.3 V 8MHz without external crystal

If you want to play a low power Arduino Standalone you can use Atmega8L at 3.3 V power with 8 Mhz internal clock:

Steps:

1 - Plug the ATMega8L micro to an Arduino board to burn bootloader.

2 - Edit burn file in bootloader folder.

    Before burn bootloader you have to change burn file

    change    --wr_fuse_l=0xdf �wr_fuse_h=0xca

    to        --wr_fuse_l=0xd4 �wr_fuse_h=0xca

    more information about fuse bytes in ATMega8 data sheet

    AVR Fuse Calculator here http://palmavr.sourceforge.net/cgi-bin/fc.cgi

3 - Download this bootloader (for ATmega8L at 8Mhz, i.e. using internal crystal). Or compile your own one from source. Backup the original ATmegaBOOT.hex file in the arduino-000x/bootloader folder. (Rename the downloaded file to ATmegaBOOT.hex.)

4 - Burn bootloader

    see http://www.arduino.cc/en/Hacking/ParallelProgrammer

    in linux you have to execute burn as root (type sudo burn)

Once you have burn the micro build this simple circuit and you can program it normally em

but you have to modify some files in Arduino IDE.

5 - Edit preferences.txt file

    change      build.f_cpu=16000000L

    to          build.f_cpu=8000000L

6 - Edit makefile

    In arduino-0007/lib/targets/arduino edit makefile

    change    F_CPU = 16000000

    to        F_CPU = 8000000

Now you are ready to buid this circuit:

7 - Program the micro, for example use led_blink example

    To program the micro you can use an Arduino board without the Atmega as a serial
    adapter or use a Mini USB adapter (as Arduino mini).

    more info: http://www.arduino.cc/en/Guide/ArduinoMini

    RX pin (Arduino board) connected to pin 2 in ATmega8L
    TX pin (Arduino board) connected to pin 3 in ATmega8L

Some info on how to make it run on 4Mhz (to lower energy consumption even more): http://www.cs.colorado.edu/~buechley/e-textile_kit/e-textile_kit_tech.html