Using atmega 8

I have a few atmega8 chips that I would like to use instead of the 328 where the code requirements are not that big.

I know the original arduino used an ATmega8, but it seems that currently there is no longer support for such chips. Is there any guide here in the forum that explains how the process can be done and more importantly with references to the required files to change in the compiler and booloaders?

Regards

Under Tools->Board select "Arduino NG or older w/ ATmega8".

Saddly the chips I have are 3.3V 8Mhz and hnce canot programmed using the above.

Pin13 flashes but the software cant communicate with the board

all m8 chips work fine with 16mhz crystal on 3.3v or 5v. ng baud with that crystal is 19.2k. with 8mhz crystal 9.6k works fine. going from one clock to the other its not necessary to change bootloader. only change 16mhz/19.2k to 8mhz/9.6k in boards.txt.

These chips have the bootloader installed? If so, you should be able to upload sketches to them. I use several mega8 but I have to manually reset the chip. As soon as compilation is done and you see "Uploading" hit the reset button.

If you don't have bootloaders, instal Optiboot. It only takes 512 bytes.

casemod: Saddly the chips I have are 3.3V 8Mhz and hnce canot programmed using the above.

Pin13 flashes but the software cant communicate with the board

Are your chips bare bone or already installed on a board? Do you have a variation of atmega8? Atmega8-16PU?

mart256:

casemod: Saddly the chips I have are 3.3V 8Mhz and hnce canot programmed using the above.

Pin13 flashes but the software cant communicate with the board

Are your chips bare bone or already installed on a board? Do you have a variation of atmega8? Atmega8-16PU?

They are standalone chips, however I want to program them using the arduino board and the atmel AVRISP programmer. Some came in a older lot of arduinos I purchased which were replaced with atmega328's, others are brand new and need to have the fuses set as I used to work a lot wih mega8's back in 2003-6, so I still have abouy 30 left from those days.

I will be operating them mostly at 3.3V in low power applications without great processing power, hence I would like to use the built in RC

I would modify the bootloader settings of "Arduino NG with Atmega8"

For 8 MHZ internal clock:

Low fuse: 0xC4 High fuse: 0xD9

Do you know how to create a new or modify an existing board? Go to boards.txt and modify "Arduino NG with Atmega8" (from arduino 1.0.5)

atmega8.name=Arduino NG or older w/ ATmega8

atmega8.upload.protocol=arduino atmega8.upload.maximum_size=7168 atmega8.upload.speed=19200

atmega8.bootloader.low_fuses=0xC4 atmega8.bootloader.high_fuses=0xD9 atmega8.bootloader.path=atmega8 atmega8.bootloader.file=ATmegaBOOT.hex atmega8.bootloader.unlock_bits=0x3F atmega8.bootloader.lock_bits=0x0F

atmega8.build.mcu=atmega8 atmega8.build.f_cpu=8000000L atmega8.build.core=arduino atmega8.build.variant=standard

Then run "burn bootloader". And later you can upload from Arduino board or avr programmer.