S3C2440定時器的使用

S3C2440定時器的使用

#include "mytimer.h"
#include "lhg_def.h"
#include "uart.h"
#include "lhg_def.h"
#include "2440addr.h"

//Timer input clock Frequency = PCLK / {prescaler value+1} / {divider value}
//PCLK=50Mhz
//prescaler : 0~255
#define prescaler234 99
//divider : 1/2,1/4,1/8,1/16 選擇為(0,1,2,3)
#define divider4 2
//定時器設置為62500HZ

void __irq timer4ISP(void) //中斷函數
{
rSRCPND |= rSRCPND|(0x1<<14);
rINTPND |= rINTPND|(0x1<<14);

Uart_Printf("now in timer4 interrupt~~ ");
}

void mytimer_init(void)//初始化定時器
{
Uart_Printf("timer4 init/r/n");
//設置中斷入口
pISR_TIMER4 = (U32)timer4ISP;
rTCFG0 &=~(0xff<<8);
rTCFG0 |= prescaler234<<8;
rTCFG1 &=~(0xf<<16);
rTCFG1 |= divider4<<16;
rTCNTB4 = 62500;//16位的 count buffer register
//rTCNTO4 = //16位的 count observation value for Time 4
rTCON |= (1<<22)|(1<<21)|(1<<20);//自動裝載，啟動定時器
rTCON &= ~0x200000 ; //定時器4開始工作
//關於中斷
rSRCPND |= rSRCPND|(0x1<<14);
rINTPND |= rINTPND|(0x1<<14);
rINTMSK &= ~(0x1<<14);
}