How many bytes a char use on program memory?

[restman]

Hi.
My problem is (if it is a problem); when i declare a variable as a constant, it uses 2 bytes on program memory. (i look at it in Proteus) Is this natural or is there any setting for this to use one byte?

Thanks for your helps...

[Ttelmah]

You don't say what processor?.
The answer varies with the chip.
On the older PIC12/16 chips, there is no ability to directly access program memory, so a single byte, is coded as the instruction:
RETLW n
Where 'n' is the value required. Here, a single byte will always use one _word_ of program memory.
On PIC16 chips where the program memory can be directly accessed, though the whole word can now be retrieved, the problem is that the word, is 14bits long, and hence can't hold two bytes. There have been programs posted here in the past, to encode two 7bit ASCII values, into one of these locations.
On the PIC18, the locations can now hold two bytes, but the bytes have to be 'word aligned' at the start of the declaration. So, if you store 5 bytes, it'll use just three words, but storing a single byte, will use one word (the same applies with the fourteen bit encoding programs mentioned above).

Best Wishes

[treitmey]

ie:
http://www.ccsinfo.com/forum/viewtopic.php?t=20782