Prevent CCS C from using EEPROM question...

Guest · Posted: Thu May 17, 2007 9:26 am

Sorry for asking such dumb question, but I'm new to CCS C and this PIC programming stuff...

My question is how do you prevent CCS C compiler from using the EEPROM space for variables, data storage, or even code (If it infact does).

I want to use (better yet reserve) some space on the EEPROM for my configuration variables.

My problem is: Upon a fresh flash of the .HEX to the PIC, I can use the EEPROM to store configuration values; however, after x number of times of turning the system off and on, I am no longer able to save new values to those same regions. What am I doing wrong.

I'm using a PIC18F4620 and PCWH 4.x

If this question is already addressed somewhere on here, please refer me to that link. Thanks in advanced.

Ttelmah · Guest

It doesn't.
How often are you writing these values?. The write life of the EEPROM, is limited, and if (for instance), you write a value every second to the EEPROM, the minimum 'life' can be used in just over a day.
If (accidentally), your code kept rebooting, or going through the 'write' routine, it is possible to use the entire life up, in just over 6 minutes!...

Best Wishes

Guest · Posted: Thu May 17, 2007 11:02 am

I wasn't sure whether CCS C compiler is generating code to use the EEPROM during runtime... but it doesn't right? Good.

I don't write the EEPROM enough to kill it... Maybe 20 times a day during testing and development. 20 x 120 bytes total around there.

Thanks for the insight on the "life" of the EEPROM -- I didn't know about that.

I need to do more digging...