Hi David,

use the "dw" assembler directive.

ie:

data  dw  0x02324, 0x02425, 0x03233...

It will store the data in the format you want into program memory and can be
read using the EEPROM program memory read commands.

myke
----- Original Message -----
From: David Williams <davidw2@MORGAN.UCS.MUN.CA>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, October 14, 1999 9:47 AM
Subject: Inefficient use of Program Memory in PIC16F877


> Hello all,
> I have a question.  I have a bunch of data that is 14 bits in size.  I'm
> using Hitech PIC-C so I've placed the data in an integer.  I've done
> something like this:
>
> const int data[256] = {0x2324,0x2425,0x3233, ..... };
>
> So I compile and I notice that in the program memory ROM the data is
> stored like this:
>
> 3F24 3F23 3F25 3F24 ....
>
> Look at all that space that could be used.  My 256 array takes up 512
> words of program memory.  Now my data is only 14 bits big.  Is there
> anyway I can delcare a variable 14 bits in size such that my constant
> table of data that is 256 14bit words big could be stored in 256 words of
> program memory?
>
> Same goes for charaters.  If I never plan to use characters with an ASCII
> value greater than 127, then can I find some efficent way to store these
> 7bit characters in program memory without using 1 word per character.  Ie
> stick two 7bit characters in 1 word of program memory.
>
> Note:  I don't want to use the write to and read from program memory
> capabilities of the PIC16F877 because that would just cause more code to
> be writen and hence more program memory occupied.  Soemthing like the
> const expression which stores values in ROM is what I'm looking for.
>
> Thanks
> Dave
>