AVR-Chat

--- In AVR-Chat@yahoogroups.com, jay marante <jaythesis@y...> wrote:
> What is the boot loader? where can i use it?
>  
> I have a project on door lock using keypad. it definitely asks for 
a password. how can will i include in my code (using ICCAVR) so that 
the EEPROM will be written only once for the administrator password 
everytime i turn on the system?

The boot loader really doesn't deal with the EEPROM (although I 
suppose it could).  The boot loader is a way to reprogram the whole 
chip (excluding the boot code, obviously) so that you can have an 
easier time of it.  It's a feature found in the newer Atmel chips.

I think all you're going to need to do is to just set a value in a 
RAM location somewhere after you've used the administrator password.  
So...when you turn on the system, the RAM location will have the 
wrong value and you'll know the admin password hasn't been used.  
After using the admin password, you set whatever EEPROM information 
you were going to set and then set the RAM and PRESTO.  You only run 
the routine once per power-up