再问一个 不信还没有人给解答 苦逼的啊...

taotiezh

再问一个 不信还没有人给解答 苦逼的啊... [复制链接]

刚看以G2553的例程 ADC10_16 其中有一句 ADC10SA = (unsigned int)&TACCR1; // Data transfer location 其中 TACCR1 的初值是 512 经运行后 ADC10SA的值变为372后不再变了 但是TACCR1的值变成563 问这是怎么个原理？这事不科学啊。。程序贴在下面 求解答另外 程序开始中的注释 直接传输code到TACCR1，这句什么意思？这会是TACCR1值变的原因吗？

//******************************************************************************
//  MSP430G2x33/G2x53 Demo - ADC10, DTC Sample A0 -> TA1, AVcc, DCO
//
//  Description: Use DTC to sample A0 with reference to AVcc and directly
//  transfer code to TACCR1. Timer_A has been configured for 10-bit PWM mode.
//  TACCR1 duty cycle is automatically proportional to ADC10 A0. WDT_ISR used
//  as a period wakeup timer approximately 45ms based on default ~1.2MHz
//  DCO/SMCLK clock source used in this example for the WDT clock source.
//  Timer_A also uses default DCO.
//
//                MSP430G2x33/G2x53
//             -----------------
//         /|\|              XIN|-
//          | |                 |
//          --|RST          XOUT|-
//            |                 |
//        >---|P1.0/A0      P1.2|--> TACCR1 - 0-1024 PWM
//
//  D. Dang
//  Texas Instruments Inc.
//  December 2010
//   Built with CCS Version 4.2.0 and IAR Embedded Workbench Version: 5.10
//******************************************************************************
#include  "msp430g2553.h"

void main(void)
{
  WDTCTL = WDT_MDLY_32;                     // WDT ~45ms interval timer
  IE1 |= WDTIE;                             // Enable WDT interrupt
  ADC10CTL0 = ADC10SHT_2 + ADC10ON;
  ADC10AE0 |= 0x01;                         // P1.0 ADC option select
  ADC10DTC1 = 0x001;                        // 1 conversion
  P1DIR |= 0x04;                            // P1.2 = output
  P1SEL |= 0x04;                            // P1.2 = TA1 output
  TACCR0 = 1024 - 1;                        // PWM Period
  TACCTL1 = OUTMOD_7;                       // TACCR1 reset/set
  TACCR1 = 512;                             // TACCR1 PWM Duty Cycle
  TACTL = TASSEL_2 + MC_1;                  // SMCLK, upmode

  while(1)
  {
    __bis_SR_register(LPM0_bits + GIE);     // LPM0, WDT_ISR will force exit
    ADC10SA = (unsigned int)&TACCR1;        // Data transfer location
    ADC10CTL0 |= ENC + ADC10SC;             // Start sampling
  }
}

#pragma vector = WDT_VECTOR
__interrupt void WDT_ISR(void)
{
  __bic_SR_register_on_exit(LPM0_bits);     // Exit LPM0
}

 

[ 本帖最后由 taotiezh 于 2012-7-20 16:14 编辑 ]