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For a few cents more, you can quadruple the amount of microcontroller program memory. The ATmega328 has 32K of Flash, 1K of EEPROM, and 2K of SRAM. This chip is pin compatible with your kit's ATmega88, but it requires three changes to your programming.
First, you must program the fuse bytes. For the '328, they are low=$F7, high=$D7, and extended=$FF. You must program these bytes with your AVRISP-II programming software. Note that there are many different values that will work, but there are also values that will 'brick' your microcontroller, rendering it almost inoperable. There is a nice online fuse calculator at http://www.engbedded.com/fusecalc/
Second, you must use the proper include file in your code. Instead of the line '.include "m88def.inc"' you must use '.include "m328def.inc"' My software didn't have this file, for some reason, but it is easy to find on the internet.
Finally, the size of the interrupt vector table is twice as large in the 328, and all of the rjmp entries in the table must be changed to jmp. Again, there are several ways to write this table. Here is one method:
.cseg .org $000 jmp RESET .org Int0addr jmp EXT_INT0 ; External Interrupt Request 0 .org Int1addr jmp EXT_INT1 ; External Interrupt Request 1 .org OVF0addr jmp OVF0 ; Timer/Counter0 Overflow .org INT_VECTORS_SIZE RESET: ;init everything here
Do these three things, and your ATmega328 chip will be happy.
Last edited by w8bh (2010-07-11 21:55:57)