User manual
142
mikoPascal PRO for PIC32
MikroElektronika
Linker Directives
mikroPascal PRO for PIC32 uses an internal algorithm to distribute objects within memory. If you need to have a
variable, constant or a routine at the specic predened address, use the linker directives absolute and org.
When using these directives, be sure to use them in proper memory segments, i.e. for functions it is the KSEG0 and
for variables it is the KSEG1. Linker directives are used with the virtual addresses.
Directive absolute
Directive absolute species the starting address in RAM for a variable. If the variable is multi-byte, higher bytes will be
stored at the consecutive locations.
Directive absolute is appended to declaration of a variable:
// Variable x will occupy 1 word (16 bits) at address 0xA0000000
var x : word; absolute 0xA0000000;
// Variable y will occupy 2 words at addresses 0xA0000000 and 0xA0000002
var y : longint; absolute 0xA0000000;
Be careful when using the absolute directive, as you may overlap two variables by accident. For example:
// Variable i will occupy 1 word at address 0xA0000002;
var i : word; absolute 0xA0000002;
// Variable will occupy 2 words at 0xA0000000 and 0xA0000002; thus,
// changing i changes jj at the same time and vice versa
var jj : longint; absolute 0xA0000000;
Directive org
Directive org species the starting address of a constant or a routine in ROM. It is appended to the constant or a routine
declaration.
To place a constant array in Flash memory, write the following :
// Constant array MONTHS will be placed starting from the address 0x9D000000
const MONTHS : array[1..12] of byte = (31,28,31,30,31,30,31,31,30,31,30,31); org
0x800;
If you want to place simple type constant into Flash memory, instead of following declaration:
const SimpleConstant : byte = 0xAA; org 0x9D000000;
use an array consisting of single element :
const SimpleConstant : array[1] of byte = (0xAA); org 0x9D000000;