AD9851串口程序.doc

#include reg52.h/*51串行驱动*/sbit clk =P11;sbit fq_ud =P12;sbit rst =P13;sbit dat =P10;/sbit key1 =P33;/sbit key2 =P34;/sbit key3 =P16;/sbit key4 =P17;unsigned char phase_word=0x00; /相位控制字，使用低5位unsigned char power_down=0x00; /低功耗模式unsigned char mult=0x00; /6倍频打开unsigned char ww5=0x09,0x0E,0x38,0xE3,0x8E;unsigned long freq,set_value;void delay_us(unsigned int i) /delay while(i-); /AD9851初始化，在此之前请确认D0,D1和D2的电平状态void init_dds(void) rst=1; /高电平复位delay_us(10000); /延时10mSrst=0;delay_us(10000); /延时10mSclk=0;fq_ud=0;delay_us(2);clk=1; /送入W0delay_us(2);clk=0;delay_us(2);fq_ud=1; /使能delay_us(2);fq_ud=0;delay_us(2);delay_us(10000);/往AD9851写数据void write_dds(unsigned long dds)unsigned char i,j,temp; ww0=dds&0xFF; /频率字最低字节ww1=(dds8)&0xFF;ww2=(dds16)&0xFF;ww3=dds24; /频率字最高字节ww4= (phase_word3)| power_down2 | mult; /控制字fq_ud=0; /FQ_UD置低clk=0; /CLK置低for(i=0;i5;i+) /送入5个字节的控制字 temp=wwi; for(j=0;j=1; clk=0;fq_ud=1; /使能信号delay_us(3);fq_ud=0;/写入频率 void write_freq(unsigned long freq) unsigned long dds; dds=128.861905*freq; /频率字计算,可进行微调/ dds=214.7483648*freq; write_dds(dds); main() /unsigned long a=0,b=0;P0=0xff; P1=0xff;delay_us(10000);init_dds();write_freq(10000000);while(1) /if(key1=0) /delay_us(10000);/while(!key1); /a+=100000;/write_freq(a);/if(key2=0) /delay_us(10000);/while(!key2);/b+=5000;/write_freq(b);/if(key3=0) delay_us(10000);while(!key3);write_