Question: How do I use the timer from C ?

Answer: Here is an example using the C3x timer.
Also included are files to use the simulator. cl30 -g vecs.asm timer.c -z timer.cmd

 
******************************* timer.c ***************************************
 
void c_int99(void)
{
        for(;;);
}
 
void c_int09(void)
{
        static unsigned int count;
 
        count++;
}
 
void main(void)
{
 volatile unsigned int* Timer0GlobalControl = (volatile unsigned int*) 0x808020;
 volatile unsigned int* Timer0Counter       = (volatile unsigned int*) 0x808024;
 volatile unsigned int* Timer0Period        = (volatile unsigned int*) 0x808028;
 
 *Timer0Period = 100;
 *Timer0GlobalControl = 0x3C1;
 asm(          or      100h, IE);
 asm(          or      2000h, ST);
 
 for(;;);
}
 
******************************* vecs.asm **************************************
 
        .sect .vecs
 
        .ref    _c_int00
        .ref    _c_int09
        .ref    _c_int99
 
reset   .word   _c_int00
int0    .word   _c_int99
int1    .word   _c_int99
int2    .word   _c_int99
int3    .word   _c_int99
xint0   .word   _c_int99
rint0   .word   _c_int99
xint1   .word   _c_int99
rint1   .word   _c_int99
tint0   .word   _c_int09
tint1   .word   _c_int99
dint    .word   _c_int99
 
***************************** timer.cmd **************************************
 
-c
-stack 0x100
-heap  0x100
-lrts30.lib
-m c3x.map
-o c3x.out
-x
-w             /* Remove if using V4.50 */
 
MEMORY
{
   ROM:    org = 0x0      len = 0x1000     /* INTERNAL 4K ROM               */
   EXT0:   org = 0x1000   len = 0x7ff000   /* EXTERNAL MEMORY               */
   XBUS:   org = 0x800000 len = 0x2000     /* EXPANSION BUS                 */
   IOBUS:  org = 0x804000 len = 0x2000     /* I/O BUS                       */
   RAM0:   org = 0x809800 len = 0x400      /* RAM BLOCK 0                   */
   RAM1:   org = 0x809c00 len = 0x400      /* RAM BLOCK 1                   */
   EXT1:   org = 0x80a000 len = 0x1000     /* EXTERNAL MEMORY               */
}
 
SECTIONS
{
   .text:   > RAM0                   /* CODE                                */
   .cinit:  > RAM0                   /* INITIALIZATION TABLES               */
   .const:  > RAM0                   /* CONSTANTS                           */
   .stack:  > RAM1                   /* SYSTEM STACK                        */
   .sysmem: > RAM1                   /* DYNAMIC MEMORY - DELETE IF NOT USED */
   .bss:    > RAM0, block 0x10000    /* VARIABLES                           */
   .vecs    > 0h
}
 
******************************* siminit.cmd ***********************************
 
ma 0x0,0x1000,ram
ma 0x808000,0x10,ram  ; 0x808010 to 0x80801F reserved mem
ma 0x808020,0x400, ram; This one and above block defines some of
                      ; the memory mapped registers. These memory maps
                      ; are must for normal execution of simulator.
                      ; If you define your own siminit, please include
                      ; these two.
ma 0x809800,0x800,ram
map on
 
********************************* timer.tak ***********************************
 
load c3x.out
c
go main
pause - Press any key
step 8
pause - Press any key
go c_int09
wa count
pause - Press any key
mix
step 1000
 
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