求一个定时器B的pwm例程

只看该作者 · 2013-10-31 00:19

求一个定时器B的pwm例程

只看该作者 · 2013-10-31 00:19

谁有分享一下吧

只看该作者 · 2013-11-1 22:45

//******************************************************************************
//  MSP430F54x Demo - Timer_B, Toggle P1.0, Overflow ISR, 32kHz ACLK
//
//  Description: Toggle P1.0 using software and the Timer_B overflow ISR.
//  In this example an ISR triggers when TB overflows. Inside the ISR P1.0
//  is toggled. Toggle rate is exactly 0.25Hz = [32kHz/FFFFh]/2. Proper use of the
//  TBIV interrupt vector generator is demonstrated.
//  ACLK = TBCLK = 32kHz, MCLK = SMCLK = default DCO ~ 1.045MHz
//
//          MSP430F5438
//       ---------------
//    /|\|             |
//    | |             |
//    --|RST          |
//       |             |
//       |          P1.0|-->LED
//
// M Smertneck / W. Goh
// Texas Instruments Inc.
// September 2008
// Built with CCE Version: 3.2.2 and IAR Embedded Workbench Version: 4.11B
//******************************************************************************

#include "msp430x54x.h"

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                // Stop WDT
  P1DIR |= 0x01;                         // Set P1.0 to output direction
  TBCTL = TBSSEL_1 + MC_2 + TBCLR + TBIE; // ACLK, contmode, clear TBR,
                                          // enable interrupt

  __bis_SR_register(LPM3_bits + GIE);    // Enter LPM3, enable interrupts
  __no_operation();                      // For debugger
}

// Timer_B7 Interrupt Vector (TBIV) handler
#pragma vector=TIMERB1_VECTOR
__interrupt void TIMERB1_ISR(void)
{
  /* Any access, read or write, of the TBIV register automatically resets the
  highest "pending" interrupt flag. */
  switch( __even_in_range(TBIV,14) )
  {
case  0: break;                         // No interrupt
case  2: break;                         // CCR1 not used
case  4: break;                         // CCR2 not used
case  6: break;                         // CCR3 not used
case  8: break;                         // CCR4 not used
case 10: break;                         // CCR5 not used
case 12: break;                         // CCR6 not used
case 14: P1OUT ^= 0x01;                // overflow
         break;
default: break;
  }
}