MSP430:PWM产生

#define     PWM                      BIT6

//  Description: This program generates one PWM output on P1.2 or P1.6 using
//  Timer_A configured for up mode. The value in CCR0, 25-1, defines the PWM
//  period and the value in CCR1 the PWM duty cycles.
//  A 50% duty cycle on P1.6.
//  ACLK = na, SMCLK = MCLK = TACLK = default DCO
void PWM_Init(void)
{
   P1DIR |= PWM;                            // P1.2 and P1.3 output
   P1SEL |= PWM;                            // P1.2 and P1.3 TA1/2 options
   CCR0 = 25-1;                             // PWM Period
   CCTL1 = OUTMOD_7;                         // CCR1 reset/set
   CCR1 = 12;                               // CCR1 PWM duty cycle
   TACTL = TASSEL_2 + MC_1;                  // SMCLK, up mode
}