问 我想利用定时器产生一个在一个周期中有多个脉宽,脉宽是变化的波形,脉宽是预先给定的.我编了个两个脉宽交替变化的程序(用C语言),仿真时用示波器看结果,不管我怎么改变定时器1的周期值,输出波形总是一样的,请问是不什么原因?我把程序贴在下面,请各位大侠帮帮我吧,谢谢!

#include "register.h"
//int T[2]={0x6000,0x8000};

void inline disable( )
{
    asm(" setc    INTM");
}

void inline enable( )
{
    asm(" clrc    INTM");
}

initial( )
{
    asm(" setc    SXM");
    asm(" clrc    OVM");
    asm(" clrc    CNF");
    *(unsigned int*)SCSR1=0x81FE;
    *(unsigned int*)WDCR=0x0E8;
    *(unsigned int*)IMR=0x0002;
    *(unsigned int*)IFR=0x0FFFF;
    *(unsigned int*)WSGR=0x00;
    
    *(unsigned int*)MCRA=*(unsigned int*)MCRA&0x0FF;
    *(unsigned int*)PBDATDIR=*(unsigned int*)PBDATDIR|0x0FF00;
    *(unsigned int*)PBDATDIR=*(unsigned int*)PBDATDIR&0x0FF00;
}

int timer1int( )
{
    *(unsigned int*)EVAIMRA=*(unsigned int*)EVAIMRA|0x0080;
    *(unsigned int*)EVAIFRA=*(unsigned int*)EVAIFRA|0x0080;
    *(unsigned int*)T1CON=0x100C;
    *(unsigned int*)T1PR=0x6000;
    *(unsigned int*)T1CNT=0x00;
}

void interrupt T1INT( )
{
    int flag,i=0,led;
    flag=*(unsigned int*)EVAIFRA&0x0080;
    if (flag!=0x0080)
    {
        enable( );
        return;
        
    }
    i=i+1;
    if(i<2)
    {
        *(unsigned int*)T1PR=0x6000;
        led=0x00FE;
    }
    if (i==2)
    {
        i=0;
        led=0x00FF;
        *(unsigned int*)T1PR=0x6000;
    }
    *(unsigned int*)T1CNT=0x00;
    *(unsigned int*)EVAIFRA=*(unsigned int*)EVAIFRA|0x0080;
    enable( );
    return;
}

void interrupt nothing( )
{
    enable( );
    return;
}


main( )
{
    int led=0x00FF;
    disable( );
    initial( );
    timer1int( );
    enable( );
    *(unsigned int*)T1CON=*(unsigned int*)T1CON|0x0040;
    while(1)
    {
        *(unsigned int*)PBDATDIR=*(unsigned int*)PBDATDIR&0x0FF00;
        *(unsigned int*)PBDATDIR=*(unsigned int*)PBDATDIR|led;
    }
}
    
    
    
    
     答 1: ...void interrupt T1INT( ) 中的变量 i ，有什么用，按照理解，你是不是想用全局变量，不然它永远不会是2 答 2: 回复主题：请教DSP2407高手关于定时器1的问题为什么不用PWM来实现呢? 答 3: 同意一楼的。定时器中的变量一般都是全局变量，否则每次进中端之后又从新初始化为0。