msp430x54x_ta_14.c

来自「MSP430的开发程序的例子+中文注释」· C语言 代码 · 共 39 行

//******************************************************************************
//  msp430FG5438 Demo - Timer_A, Toggle P1.1/TA0, Up/Down Mode, 32kHz ACLK
//
//  Description: Toggle P1.1 using hardware TA0 output. Timer_A is configured
//  for up/down mode with CCR0 defining period, TA0 also output on P1.1. In
//  this example, CCR0 is loaded with 5 and TA0 will toggle P1.1 at TACLK/2*5.
//  Thus the output frequency on P1.1 will be the TACLK/20. No CPU or software
//  resources required. Normal operating mode is LPM3.
//  As coded with TACLK = ACLK, P1.1 output frequency = 32768/20 = 1.6384kHz
//  ACLK = TACLK = 32kHz, MCLK = default DCO ~1.045MHz
//
//              msp430FG5438
//            -----------------
//        /|\|                 |
//         | |                 | 
//         --|RST              |
//           |                 |
//           |             P1.1|-->TA0 ACLK/20
//
//   M Smertneck
//   Texas Instruments Inc.
//   April 2008
//   Built with CCEv3.2 IAR Embedded Workbench Version: 3.42A
//******************************************************************************

#include <msp430x54x.h>

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  P1DIR |= 0x02;                            // P1.1 output
  P1SEL |= 0x02;                            // P1.1 option select
  TA0CCTL0 = OUTMOD_4;                      // CCR0 toggle mode
  TA0CCR0 = 5;
  TA0CTL = TASSEL_1 + MC_3;                 // ACLK, up-downmode

  _BIS_SR(LPM3_bits);                       // Enter LPM3
}