rockbox/firmware/target/arm/s3c2440/gigabeat-fx/kernel-meg-fx.c
Karl Kurbjun 67ef4500e3 More interupt/timer work
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@14823 a1c6a512-1295-4272-9138-f99709370657
2007-09-22 23:17:52 +00:00

60 lines
1.4 KiB
C

#include "config.h"
#include "system.h"
#include "kernel.h"
#include "timer.h"
#include "thread.h"
extern void (*tick_funcs[MAX_NUM_TICK_TASKS])(void);
void tick_start(unsigned int interval_in_ms)
{
/*
* Based on default PCLK of 49.1568MHz - scaling chosen to give
* remainder-free result for tick interval of 10ms (100Hz)
* Timer input clock frequency =
* fPCLK / {prescaler value+1} / {divider value}
* TIMER_FREQ = 49156800 / 2
* 13300 = TIMER_FREQ / 231 / 8
* 49156800 = 19*(11)*(7)*7*5*5*(3)*2*2*2*2*2*2
* 231 = 11*7*3
*/
/* stop timer 4 */
TCON &= ~(1 << 20);
/* Set the count for timer 4 */
TCNTB4 = (TIMER_FREQ / 231 / 8) * interval_in_ms / 1000;
/* Set the the prescaler value for timers 2,3, and 4 */
TCFG0 = (TCFG0 & ~0xff00) | ((231-1) << 8);
/* MUX4 = 1/16 */
TCFG1 = (TCFG1 & ~0xff0000) | 0x030000;
/* set manual bit */
TCON |= 1 << 21;
/* reset manual bit */
TCON &= ~(1 << 21);
/* interval mode */
TCON |= 1 << 22;
/* start timer 4 */
TCON |= (1 << 20);
/* timer 4 unmask interrupts */
INTMSK &= ~TIMER4_MASK;
}
void TIMER1(void)
{
int i;
/* Run through the list of tick tasks */
for(i = 0; i < MAX_NUM_TICK_TASKS; i++)
{
if(tick_funcs[i])
{
tick_funcs[i]();
}
}
current_tick++;
SRCPND = TIMER4_MASK;
INTPND = TIMER4_MASK;
}