PWM波程序求助

伍师傅32 · 发表于 2012-5-2 16:20:13

看着芯片手册，我写了一段产生PWM控制LED亮度的程序。目的是实现按键按下，PWM的占空比产生变化。按键采用外部中断。我想利用TA1计数器进行按键消抖，可是不知道为什么TA1的中断一直进不去。在仿真的过程中，每次程序进入中断后，TA0CCR1的值都会回到初始化时的值，所以PWM的占空比就无法通过按键进行控制。我看了好久，还是不清楚到底哪里出了毛病。希望大家能够指点一下，本人不胜感激！下面是源程序：
#include<msp430g2553.h>

unsigned char state = 0;
unsigned int count = 0;
unsigned int temp;

void main( void )
{
  // Stop watchdog timer to prevent time out reset
  WDTCTL = WDTPW + WDTHOLD;
  BCSCTL1 = CALBC1_1MHZ;
  DCOCTL = CALDCO_1MHZ;
  P1SEL |= BIT6;
  P1DIR |= BIT6 + BIT0;
  P1OUT &= ~BIT0;
  P1REN |= BIT3;
  P1IE |= BIT3;
  P1IES |= BIT3;
  P1IFG &= ~BIT3;

  TACTL |= MC_1 + TASSEL_2;
  TA1CTL |= MC_1 + TASSEL_2 + ID_2;
  TACCTL1 = OUTMOD_7;
  TACCR0 = 1000;
  TACCR1 = temp;
  _BIS_SR(GIE);
//  while(1);
  _BIS_SR(LPM0_bits + GIE);
}

#pragma vector = PORT1_VECTOR
__interrupt void P1_EX(void)
{
  if((P1IFG & BIT3) == BIT3)                            //只要一进这个中断，TACCR1就被还原到初始值了
  {
P1IE &= ~BIT3;
TA1CCR0 = 5000;
TA1CCTL0 = CCIE;
P1IFG &= ~BIT3;
count++;
temp = TACCR1;
if(state == 0)
{
   if(temp < 950)
      temp += 50;
   else
      state = 1;
}
else
{
   if(temp > 50)
      temp -= 50;
   else
      state = 0;
}
TA0CCR1 = temp;
  }
}

#pragma vector = TIMER0_A1_VECTOR
__interrupt void Timer_A1(void)
{
  if((TA1CCTL0 & CCIFG) == CCIFG)                               //这个中断就一直进不来
  {
if((P1IN & BIT3) == 0)
{
   P1OUT ^= BIT0;
   if(state == 0)
   {
      if(TACCR1 < 950)
      TACCR1 += 50;
      else
      state = 1;
   }
   else
   {
      if(TACCR1 > 50)
      TACCR1 -= 50;
      else
      state = 0;
   }
}
TA1CCTL0 &= ~CCIFG;
  }
  P1IE |= BIT3;
  TA1CCTL0  &= ~CCIE;
}

PWM波程序求助

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