MSP430G2553 PWM 占空比乱跳问题

1万 · 2014-6-20 08:10

调一个死值的占空比没事 ,我将占空比 100% 慢慢降到 0% 快到 0%时
出现一次占空比100%的一个脉冲 LED灯闪一下,调光中间不闪.
现在还不知道是我程序的BUG还是这IC本来就有这鸟问题不能用于调光.
这要命 ,,,

我已经在 PWM 那路中断中去更新占空比了,
前面我还试了在MAIN中更新和另一组定时器中更新  结果就是中间不断有闪烁感有时无.

我用的是MSP430G2553

//===========================================================================
TA1CCR0 = Lum100-1;                         // PWM Period 1000us/(1/8MHZ) 这里不减1 高电平还不能到100%
TA1CCR1 = 0;//PWM1_duty_cycle_Val;                      // CCR1 PWM duty cycle 2.1
TA1CCR2 = 0;//PWM1_duty_cycle_Val;                      // CCR2 PWM duty cycle 2.4

TA1CCTL0 = CCIE;                         // CCR0 interrupt enabled  就用这个中断
TA1CCTL1 = OUTMOD_7;                   // CCR1 reset/set
TA1CCTL2 = OUTMOD_7;                   // CCR2 reset/set
TA1CTL = TASSEL_2 + TACLR + MC_1;       // SMCLK, up mode

然后定时中断更新

// Timer1 A0 interrupt service routine
#pragma vector=TIMER1_A0_VECTOR //TA1 CCR0
__interrupt void Timer1_A0 (void)  //1khz
{
   TA1CCR1 = PWM1_duty_cycle;
   TA1CCR2 = PWM1_duty_cycle;
}

1万 · 2014-6-20 08:56

#include <msp430.h>

typedef unsigned char  u8;
typedef unsigned int u16;
typedef unsigned long  u32;

typedef signed char s8;
typedef signed int    s16;
typedef signed long s32;

#define LED1()                   (P2OUT ^=  BIT0)

#define PWM1_duty_cycle_Val       8000

u16 PWM1_duty_cycle          = 0;
u16 PWM1_duty_cycle_CCR       = 0;

//=============================================================================
void InitSystemClock(void)
{
BCSCTL1 = CALBC1_8MHZ;
DCOCTL  = CALDCO_8MHZ; // DCO 8MHZ

FCTL2 = FWKEY + FSSEL0 + 0x18;          // MCLK/3 for Flash Timing 8M / 25 320K  //FLASH IN 257-476KHZ

}

//=============================================================================
void Init_IO(void)
{

P2DIR |=BIT0;                         //P2.0 Output LED

//P2OUT &= ~BIT1;                         //LOW
//P2OUT |= BIT1;                         //HIGH

P2DIR |= BIT1;                         // P2.1 pwm output  详见硬件手册
P2SEL |= BIT1;                         // P2.1 Pin9 Multiplexing
//P2DIR |= BIT2;                         // P2.1 pwm output  2.1 2.2只能输出相同波形
//P2SEL |= BIT2;                         // P2.1 Pin9

//P2OUT &= ~BIT4;                         //LOW
P2DIR |= BIT4;                         // P2.4 pwm output
P2SEL |= BIT4;                         // P2.4 Pin12  Multiplexing
//P2DIR |= BIT5;                         // P2.4 pwm output  2.4 2.5只能输出相同波形
//P2SEL |= BIT5;                         // P2.4 Pin12

}

//=============================================================================
void InitPWM(void)
{
/*
//===========================================================================
TA0CCR0 = 2550;                         // PWM Period
TA0CCR1 = 1000;                            // CCR1 PWM duty cycle
//TA0CCR2 = 800;                            // CCR2 PWM duty cycle 28Pins

TA0CCTL0 = CCIE;                         // CCR0 interrupt enabled
//TA0CCTL1 = OUTMOD_7;                   // CCR1 reset/set
//TA0CCTL2 = OUTMOD_7;                   // CCR2 reset/set 28Pins
TA0CTL = TASSEL_2 + TACLR + MC_1;          // SMCLK, up mode  定时器_A 控制寄存器
*/
//===========================================================================
TA1CCR0 = PWM1_duty_cycle_Val-1;                         // PWM Period 1000us/(1/8MHZ)
TA1CCR1 = 0;//PWM1_duty_cycle_Val;                      // CCR1 PWM duty cycle 2.1
TA1CCR2 = 0;//PWM1_duty_cycle_Val;                      // CCR2 PWM duty cycle 2.4

TA1CCTL0 = CCIE;                         // CCR0 interrupt enabled
TA1CCTL1 = OUTMOD_7;                   // CCR1 reset/set
TA1CCTL2 = OUTMOD_7;                   // CCR2 reset/set
TA1CTL = TASSEL_2 + TACLR + MC_1;       // SMCLK, up mode

}

// Timer1 A0 interrupt service routine
#pragma vector=TIMER1_A0_VECTOR //TA1 CCR0
__interrupt void Timer1_A0 (void)  //1khz
{
if (PWM1_duty_cycle_CCR < PWM1_duty_cycle) //Smooth
{
PWM1_duty_cycle_CCR++;
}
else if (PWM1_duty_cycle_CCR > PWM1_duty_cycle)
{
if (PWM1_duty_cycle_CCR)
PWM1_duty_cycle_CCR--;
}

   TA1CCR1 = PWM1_duty_cycle_CCR;
   TA1CCR2 = PWM1_duty_cycle_CCR;

}

//=============================================================================
void DelaymS(unsigned int n)
{
volatile u16 i = 0;
volatile u16 j = 0;

for (i=n;i>0;i--)
{
   for (j=680;j>0;j--)
   {
   _NOP();
   }
}

}

/*
* main.c
*/
int main(void)
{
int i = 0;

_DINT();                   // disable_interrupt

WDTCTL = WDTPW | WDTHOLD; // Stop watchdog timer

InitSystemClock();

InitPWM();    //TA1

Init_IO();

_EINT() ;                   // enable_interrupt

while(1)
{
LED1();
      if (++i == 1)
      {
      PWM1_duty_cycle = 0;
      }
      else if (i == 2)
      {
        i = 0;
        PWM1_duty_cycle = PWM1_duty_cycle_Val;
      }
      DelaymS(3000);
}

//return 0;
}