timer.c

DSP的配置TIMERO进行计数并产生中断,通过调用中断服务子程序,进行处理

/*
 *  Copyright 2003 by Texas Instruments Incorporated.
 *  All rights reserved. Property of Texas Instruments Incorporated.
 *  Restricted rights to use, duplicate or disclose this code are
 *  granted through contract.
 *  
 */
/* "@(#) DSP/BIOS 4.90.270 06-11-03 (barracuda-m10)" */
/******************************************************************************\
*           Copyright (C) 2000 Texas Instruments Incorporated.
*                           All Rights Reserved
*------------------------------------------------------------------------------
* FILENAME...... timer.c
* DATE CREATED.. 01/11/2000
* LAST MODIFIED. 01/04/2001
\******************************************************************************/

#include <stdio.h>

#include <csl.h>
#include <csl_irq.h>
#include <csl_timer.h>
#include <csl_chiphal.h>

/* This is a simple timer example to set the timer with */
/* an interrupt period of 0x400 cycles.                 */

/* The example uses predefined CSL macros and symbolic  */
/* constants to create the correct register settings    */
/* needed to configure the timer.                       */


/* Reference start of interrupt vector table   */
/* This symbol is defined in file, vectors.s55 */
extern void VECSTART(void);

#define TIMER_CTRL    TIMER_TCR_RMK(\
                      TIMER_TCR_IDLEEN_DEFAULT,    /* IDLEEN == 0 */ \
                      TIMER_TCR_FUNC_OF(0),        /* FUNC   == 0 */ \
                      TIMER_TCR_TLB_RESET,         /* TLB    == 1 */ \
                      TIMER_TCR_SOFT_BRKPTNOW,     /* SOFT   == 0 */ \
                      TIMER_TCR_FREE_WITHSOFT,     /* FREE   == 0 */ \
                      TIMER_TCR_PWID_OF(0),        /* PWID   == 0 */ \
                      TIMER_TCR_ARB_RESET,         /* ARB    == 1 */ \
                      TIMER_TCR_TSS_START,         /* TSS    == 0 */ \
                      TIMER_TCR_CP_PULSE,          /* CP     == 0 */ \
                      TIMER_TCR_POLAR_LOW,         /* POLAR  == 0 */ \
                      TIMER_TCR_DATOUT_0           /* DATOUT == 0 */ \
)  


/* Create a TIMER configuration structure that can be passed */
/* to TIMER_config CSL function for initialization of Timer  */
/* control registers.                                        */
TIMER_Config timCfg0 = {
   TIMER_CTRL,               /* TCR0 */
   0x3400u,                  /* PRD0 */
   0x0000                    /* PRSC */
};


Uint16 eventId0;  

/* Create a TIMER_Handle object for use with TIMER_open */
TIMER_Handle mhTimer0;

volatile Uint16 timer0_cnt = 0;

/* Function/ISR prototypes */
interrupt void timer0Isr(void);
void taskFxn(void);

int old_intm;
Uint16 tim_val;
Uint16 xfchange = 0;

void main(void)
{
	 /* Initialize CSL library - This is REQUIRED !!! */
	 /*CLS库的初始化，这是必需的*/
	 CSL_init();
	
	 /* Set IVPH/IVPD to start of interrupt vector table */
	 /*修改寄存器IVPH，IVPD，重新定义中断向量表*/
	 IRQ_setVecs((Uint32)(&VECSTART));
	 
	 /* Temporarily disable all maskable interrupts */
	/*禁止所有可屏蔽的中断源*/
	old_intm = IRQ_globalDisable();   
	
	/* Open Timer 0, set registers to power on defaults */
	/*打开定时器0，设置其为上电的的默认值，并返回其句柄*/
	mhTimer0 = TIMER_open(TIMER_DEV0, TIMER_OPEN_RESET);
	
	/* Get Event Id associated with Timer 0, for use with */
	/* CSL interrupt enable functions.                    */
	/*获取定时器0的中断ID号*/         
	eventId0 = TIMER_getEventId(mhTimer0);
	
	/* Clear any pending Timer interrupts */
	/*清除定时器0的中断状态位*/
	IRQ_clear(eventId0);
	
	/* Place interrupt service routine address at */
	/* associated vector location */
	/*为定时器0设置中断服务程序*/
	IRQ_plug(eventId0,&timer0Isr);
	
	/* Write configuration structure values to Timer control regs */
	/*设置定时器0的控制与周期寄存器*/ 
	TIMER_config(mhTimer0, &timCfg0);  
	
	/* Enable Timer interrupt */
	/*使能定时器的中断*/
	IRQ_enable(eventId0);             
	
	/* Enable all maskable interrupts */
	/*设置寄存器ST1的INTM位，使能所有的中断*/
	IRQ_globalEnable();      
	
	/* Start Timer */
	/*启动定时器0*/
	TIMER_start(mhTimer0);
	    
	for(;;)
	{
		/* Wait for at least 10 timer periods */
	    /*等待10个定时周期*/
		if(xfchange == 0) 
		{
		   /*点亮XF的LED*/
		   CHIP_FSET(ST1_55,XF,1);  
		}
		else
		{
			/*关掉XF的LED*/
		  	CHIP_FSET(ST1_55,XF,0); 
		}
	}
	
	
	/* Restore old value of INTM */
	/*恢复INTM旧的值*/
	IRQ_globalRestore(old_intm);
	
	/* We are through with timer, so close it */
	/*关掉定时器0*/
	TIMER_close(mhTimer0); 
}
/*定时器0的中断程序*/
interrupt void timer0Isr(void)
{
    ++timer0_cnt;
    if(timer0_cnt == 500)
    {
    	xfchange = 1;
    }
    if(timer0_cnt == 1000)
    {
    	timer0_cnt = 0;
    	xfchange = 0;	
    }
}