dds.c

该代码来自2008年湖北电子设计大赛位移测量装置制作,主要实现位移的自动测量和手动测量,msp430单片机

#include"dds.h"
void delay(int m)
{
  int i=1000*m;
  for(;i>0;i--);
}
void init_dds(void) 
{ 
    outport;
    POUT=0;
    rest;
    delay(1);
    rest0;
    delay(1);
    clk0; 
    load0; 
    delay(2); 
    clk1; 
    delay(2); 
    clk0; 
    delay(5); 
    load1; 
    delay(2); 
    load0; 
    
} 
//写入 40bit 到 DDS 芯片,频率占用前 32bit,相位暂不可调 
void write_dds(unsigned long dds) 
{ 
    uchar i; 
    load0; 
    clk0; 
    int m=0x09;
    for(i=0;i<40;i++) 
    { 
      clk0; 
      delay(1); 
       if(dds & 0x00000001)dat1; 
       else dat0; 
      delay(1); 
      clk1; 
      dds = dds >> 1;
      delay(2); 
    }
   /* for(;i<40;i++)
    {
      clk0; 
      delay(1); 
      if(m & 0x00000001)dat1; 
      else dat0; 
      delay(1); 
      clk1; 
      m = m >> 1;
      delay(2); 
    }*/
    load1; 
    clk0; 
    delay(10); 
    load0; 
} 
//输出你要的频率 
void write_freq(unsigned long freq) 
{ 
    unsigned long dds; 
    dds =34.359738368 * freq;// pow(2,32)*freq/(30*pow(10,6));//34.359738368 * freq; //dds=2^32*freq/clk(晶振)
    write_dds(dds); 
}