Retrieving variables contents after power off.

[uni_student]

Hi, trying to store a value that changes into a variable, int mode; , switch off power to pic, and turn back on and retrieve the last value that was in that variable. Does declaring int mode; always store the variable in same space of memory every time switched on? How do i allocate to known part of memory if not the case? Cheers

[PCM programmer]

This example show how to save a variable in internal eeprom and
restore it upon power-up.
http://www.ccsinfo.com/forum/viewtopic.php?t=22109&start=17

However, remember that internal eeprom has a limited number of
writes (lifespan). For the 16F877, the limit is 100K. In the example
in that link, the number of write operations will be relatively small.

[uni_student]

Thanx for reply,

in the line

[jbmiller]

Each microcomputer has a 'memory map' that defines where what type of memory is located. The datasheets describe it in detail.EACH series of chips will be different(RAM,ROM, EEPROM, Peripherals,etc.)

Random Access Memory is volatile,used for dynamic variables...
Read Only Memory is programmed ONCE during the 'burning 'process'...
Electricallly Erasable program Memory can be reprogrammed when the program is running.....

Peripherals include all the 'I/O ports' and modules(timers,config locations,etc.)

[andrewg]

The address can be determined automatically: