DDS AD9959应用电路和配置源程序AD9959是一款有四个DDS通道，最高达500M SPS的数字频率合成芯片。 常用电路接法：主要程序：#include "config.h"void delay(void){ unsigned int i; for(i=0;i<10;i++);}/*****************************************************************************功能描述: 加载寄存器，上升延有效*****************************************************************************/ void run(void){ CLR_IOUPDATE; CLR_IOUPDATE; CLR_IOUPDATE; CLR_IOUPDATE; CLR_IOUPDATE; CLR_IOUPDATE; CLR_IOUPDATE; SET_IOUPDATE; SET_IOUPDATE; }/*****************************************************************************函数名: write_a_byte功能描述: 通过串口写一个字节，MSB first，上升延有效*****************************************************************************/ void write_a_byte(uint8 w_data){ uint8 i; for(i=0;i<8;i++) { if(w_data & 0x80) { SET_SDIO0; } else { CLR_SDIO0; } w_data <<= 1; SET_DDSSCLK; CLR_DDSSCLK; }}/*****************************************************************************函数名: write_CSR功能描述: 写CSR寄存器：*****************************************************************************/ void write_CSR(uint8 w_data){ CLR_SDIO3; CLR_DDSCS; write_a_byte(0x00); //write address 0. CSR's address is 0. write_a_byte(w_data); SET_DDSCS; SET_SDIO3;}void write_FR1(uint8 w_data1,uint8 w_data2,uint8 w_data3){ CLR_SDIO3; CLR_DDSCS; write_a_byte(0x01); //write address 1. FR1's address is 0x01 write_a_byte(w_data1); write_a_byte(w_data2); write_a_byte(w_data3); SET_DDSCS; SET_SDIO3;}void write_FR2(uint8 w_data1,uint8 w_data2){ CLR_SDIO3; CLR_DDSCS; write_a_byte(0x02); //write address 2 write_a_byte(w_data1); write_a_byte(w_data2); SET_DDSCS; SET_SDIO3;}void write_CFR(uint8 w_data1,uint8 w_data2,uint8 w_data3){ CLR_SDIO3; CLR_DDSCS; write_a_byte(0x03); write_a_byte(w_data1); write_a_byte(w_data2); write_a_byte(w_data3); SET_DDSCS; SET_SDIO3;}void write_CTW0(uint32 F_word) //Channel Frequency Tuning Word (CTW0){ CLR_SDIO3; CLR_DDSCS; write_a_byte(0x04); write_a_byte(((unsigned char *)(&F_word))[3]); write_a_byte(((unsigned char *)(&F_word))[2]); write_a_byte(((unsigned char *)(&F_word))[1]); write_a_byte(((unsigned char *)(&F_word))[0]); SET_DDSCS; SET_SDIO3;}void write_CPW0(uint16 P_word) //Channel Phase1 Offset Word (CPW0) (0x05){ CLR_SDIO3; CLR_DDSCS; write_a_byte(0x05); write_a_byte(((unsigned char *)(&P_word))[1]&0x3F); write_a_byte((((unsigned char *)(&P_word))[0])); SET_DDSCS; SET_SDIO3;}void write_ACR(uint32 A_word){ CLR_SDIO3; CLR_DDSCS; write_a_byte(0x06); write_a_byte(((unsigned char *)(&A_word))[3]); write_a_byte(((unsigned char *)(&A_word))[2]); write_a_byte(((unsigned char *)(&A_word))[1]); SET_DDSCS; SET_SDIO3;}void write_LSR(uint8 rising,uint8 falling){ CLR_SDIO3; CLR_DDSCS; write_a_byte(0x07); write_a_byte(rising); write_a_byte(falling); SET_DDSCS; SET_SDIO3;}void write_RDW(uint32 rising){ CLR_SDIO3; CLR_DDSCS; write_a_byte(0x08); write_a_byte(((unsigned char *)(&rising))[3]); write_a_byte(((unsigned char *)(&rising))[2]); write_a_byte(((unsigned char *)(&rising))[1]); write_a_byte(((unsigned char *)(&rising))[0]); SET_DDSCS; SET_SDIO3;}void write_FDW(uint32 falling){ CLR_SDIO3; CLR_DDSCS; write_a_byte(0x09); write_a_byte(((unsigned char *)(&falling))[3]); write_a_byte(((unsigned char *)(&falling))[2]); write_a_byte(((unsigned char *)(&falling))[1]); write_a_byte(((unsigned char *)(&falling))[0]); SET_DDSCS; SET_SDIO3;}void write_CTWn(uint8 n,uint32 w_data){ CLR_SDIO3; CLR_DDSCS; write_a_byte(n+0x09); //CTWn's address is n+0x09.n>=1 and n<=15. write_a_byte(((unsigned char *)(&w_data))[3]); write_a_byte(((unsigned char *)(&w_data))[2]); write_a_byte(((unsigned char *)(&w_data))[1]); write_a_byte(((unsigned char *)(&w_data))[0]); SET_DDSCS; SET_SDIO3;}#define PLL_DIV 5#define systemp_frequency (22.1184*1000000*PLL_DIV)void set_frequency(uint32 f){ unsigned long int temp; temp=(unsigned long int)f*(0xFFFFFFFF/(float)systemp_frequency+1.0/systemp_frequency); write_CTW0(temp);}uint32 change(uint32 f){ unsigned long int temp; temp=(unsigned long int)f*(0xFFFFFFFF/(float)systemp_frequency+1.0/systemp_frequency); return temp;}void AD9959_init(void){ uint16 i; DDS_DDR = 0xff; CLR_DDSRESET; for(i=0;i<10000;i++); SET_DDSCS; CLR_DDSSCLK; SET_SDIO3; SET_DDSRESET; for(i=0;i<10000;i++); CLR_DDSRESET; for(i=0;i<100;i++);}