我的程序能够成功运行，但是正弦波的频率居然才30Hz，让我很不解，不知道是DA转换的速度问题（DA转换的程序是百度的），还是还是内部时钟的问题，求助！！

#include <msp430g2553.h>
#define uchar unsigned char
#define uint unsigned int
#define AddWr 0x90
#define SDA BIT0
#define SCL BIT1
#define delay_ms(x) __delay_cycles((long)(CPU_F*(double)x/1000.0))
const uchar mysin[256]={
  0x7F,0x82,0x85,0x88,0x8B,0x8F,0x92,0x95,0x98,0x9B,
  0x9E,0xA1,0xA4,0xA7,0xAA,0xAD,0xB0,0xB3,0xB6,0xB8,
  0xBB,0xBE,0xC1,0xC3,0xC6,0xC8,0xCB,0xCD,0xD0,0xD2,
  0xD5,0xD7,0xD9,0xDB,0xDD,0xE0,0xE2,0xE4,0xE5,0xE7,
  0xE9,0xEB,0xEC,0xEE,0xEF,0xF1,0xF2,0xF4,0xF5,0xF6,
  0xF7,0xF8,0xF9,0xFA,0xFB,0xFB,0xFC,0xFD,0xFD,0xFE,
  0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,
  0xFD,0xFD,0xFC,0xFB,0xFB,0xFA,0xF9,0xF8,0xF7,0xF6,
  0xF5,0xF4,0xF2,0xF1,0xEF,0xEE,0xEC,0xEB,0xE9,0xE7,
  0xE5,0xE4,0xE2,0xE0,0xDD,0xDB,0xD9,0xD7,0xD5,0xD2,
  0xD0,0xCD,0xCB,0xC8,0xC6,0xC3,0xC1,0xBE,0xBB,0xB8,
  0xB6,0xB3,0xB0,0xAD,0xAA,0xA7,0xA4,0xA1,0x9E,0x9B,
  0x98,0x95,0x92,0x8F,0x8B,0x88,0x85,0x82,0x7F,0x7C,
  0x79,0x76,0x73,0x6F,0x6C,0x69,0x66,0x63,0x60,0x5D,
  0x5A,0x57,0x54,0x51,0x4E,0x4B,0x48,0x46,0x43,0x40,
  0x3D,0x3B,0x38,0x36,0x33,0x31,0x2E,0x2C,0x29,0x27,
  0x25,0x23,0x21,0x1E,0x1C,0x1A,0x19,0x17,0x15,0x13,
  0x12,0x10,0x0F,0x0D,0x0C,0x0A,0x09,0x08,0x07,0x06,
  0x05,0x04,0x03,0x03,0x02,0x01,0x01,0x00,0x00,0x00,
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x01,
  0x02,0x03,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,
  0x0C,0x0D,0x0F,0x10,0x12,0x13,0x15,0x17,0x19,0x1A,
  0x1C,0x1E,0x21,0x23,0x25,0x27,0x29,0x2C,0x2E,0x31,
  0x33,0x36,0x38,0x3B,0x3D,0x40,0x43,0x46,0x48,0x4B,
  0x4E,0x51,0x54,0x57,0x5A,0x5D,0x60,0x63,0x66,0x69,
  0x6C,0x6F,0x73,0x76,0x79,0x7C};

void Time_A0_init()
{
  TACTL |= TASSEL_2 + MC_2;
  CCR0 = tcr;
  CCTL0 |= CCIE;
}
void sda_high(void)
{
  P1DIR |=SDA;
  P1OUT |=SDA;
}
void sda_low(void)
{
  P1DIR |=SDA;
  P1OUT &= ~(SDA);
}
void scl_high(void)
{
  P1DIR |= SCL;
  P1OUT |= SCL;
}
void scl_low(void)
{
  P1DIR |=SCL;
  P1OUT &= ~(SCL);
}
void Start_I2c()
{
   sda_high();
   _NOP();
   scl_high();
   _NOP();
  _NOP();
   _NOP();
   _NOP();
   _NOP();
   sda_low();
   _NOP();
  _NOP();
   _NOP();
   _NOP();
   _NOP();
   scl_low();
   _NOP();
   _NOP();
}
void Stop_I2c()
{
   sda_low();
   _NOP();
   scl_high();
   _NOP();
  _NOP();
   _NOP();
   _NOP();
   _NOP();
   sda_high();
   _NOP();
  _NOP();
   _NOP();
   _NOP();
}
void  SendByte(uchar data)
{
uchar BitCnt;
  for(BitCnt=0;BitCnt<8;BitCnt++)
  {
      if((data<<BitCnt)&0x80)
       sda_high();
       else  sda_low();
      _NOP();
      scl_high();
   _NOP();
   _NOP();
   _NOP();
   _NOP();
   _NOP();
     scl_low();
  }
     _NOP();
     _NOP();
     sda_high();
     _NOP();
     _NOP();
     scl_high();
    _NOP();
    _NOP();
    _NOP();
    scl_low();
    _NOP();
    _NOP();
}
void WriteDAC(uchar dat)
{
   Start_I2c();
   SendByte(AddWr);
   SendByte(0x40);
   SendByte(dat);
   Stop_I2c();
}
void main(void)
{
WDTCTL = WDTPW + WDTHOLD;
BCSCTL1 = CALBC1_16MHZ;
DCOCTL = CALDCO_16MHZ;
Time_A0_init();
uint i=0;
while(1)
{
  if(i < 256)
      {
     WriteDAC(mysin);
     i++;
      }
    else
     i=0;
}
}


此帖出自小平头技术问答