atmega8,, program counter 12 bits...so how it will access full 8kb of memory flash...

[beyondH]

hellow experts,,

I am starting with the AVRs, so it may be a very silly question..but i am stuck with it...
since i got to know that the program counter of atmega8 is of 12bits...and the flash memory is of 8KB , how can we access the remaining memory....

does the remaining memory is reserved for the bootloader section(modifiable via the fuse bits)...
kindly tell me the exact application section and the bootloader section memory division??
i am confused....

 

[alexxx]

since i got to know that the program counter of atmega8 is of 12bits...and the flash memory is of 8KB , how can we access the remaining memory....

Even though I don't use assembly, I remember that PC keeps 16-bit addresses:

The ATmega8 contains 8Kbytes On-chip In-System Reprogrammable Flash memory for program storage. Since all AVR instructions are 16-bits or 32-bits wide, the Flash is organized as 4K × 16 bits.
.......................
The ATmega8 Program Counter (PC) is 12 bits wide, thus addressing the 4K Program memory locations.

http://www.atmel.com/dyn/resources/prod_documents/doc2486.pdf

 

[beyondH]

first of all thnx. for the reply sir,,
so,,
can i say like "in atmega8, using assembly i can go upto a maximum of 4096 number of instructions assuming every instruction takes 16 bits(here),."??

 

[alexxx]

can i say like "in atmega8, using assembly i can go upto a maximum of 4096 number of instructions assuming every instruction takes 16 bits(here),."??

Since it is written in the datasheet it is not assumed any more, it's a fact. :smile:

This reference about AVR instruction set may be helpful.
http://www.atmel.com/dyn/resources/prod_documents/doc0856.pdf