arduino board (atmega8 dev)

Forum 2005-2010 (read only) Hardware Development
1

Hi,

I have an STK 500v2 programmer which uses a USB to serial converter.I have an atmega8.I have been trying to make the older arduino board but during my trials I bricked 5 atmega 8 chips.

My question:
1)How to upload the bootloader (board to work at 8Mhz internal oscillator)
Please tell me a step by ste process.

2)How shall I upload sketched without using the bootloader.

(I have looked at some pages in arduino website but could not get it working).

My frustration only grows with each atmega 8 that I brick.

2

Also I think that I need to recompile the bootloader source code by modifying the make file.The atmega8 for 8Mhz I have been using are hfuse=D9 and lfuse=E4 .Also I want to do it at 9600 baud.Could some please suggest me how to recompile the boot loader source code.I have WinAVR

3

I think you need to use the Lilypad bootloader.

You can upload sketches directly to the chip if you have an external programmer.

4

You cannot compile the Mega8 bootloader using the current version of AVR-GCC supplied.

Download an old version of GCC something < version 4 . Then compile.

I could not makefile supplied to work , so had to make a new one when i built a custom mega8 bootloader.

5

Bricking an AVR has nothing really to do with the programmer you are using and everything to do with the fuse bits. If you set the wrong clock bits [CKSEL3..0], [SUT1..0] then it is very easy to brick one. It is possible to recover most bricked AVRs by using High Voltage Parallel Programming Mode as found on the STK500. There are even specialist boards made for this purpose.

I'm not sure where you got those fuse settings from, but the correct ones are HFUSE 0xCA and LFUSE 0xDF assuming an external crystal oscillator. Here is a detailed page that explains all. Alternatively you can check the fuses with this interactive fuse calculator.

It should be possible to use the 8MHz mega8 at 9600 baud as you have the same bit errors as 16 MHz. To set the correct clock speed and baud rate, change the Makefile as follows:

DEFS= -DF_CPU=8000000 -DBAUD_RATE=9600