//PIC16F877单片机输出正弦波信号仿真原理图如下（proteus仿真工程文件可到本帖附件中下载）
//20MHz晶振，输出500Hz的正弦波，每周波100个点。
//1个周期时间为2ms,二点间隔时间为2000/100=20us
//用TMR2延时,256*Tcy*K=20,Tcy=0.2,取K=1
//PR2计算：(PR2+1)*Tcy*1=20,得PR2=99
#include <pic.h>
__CONFIG(0x3F3A);
#define CS RB1
#define LDAC RB2
char BUF,N;
#define nn 100
const unsigned int SS[100]={
2048,2111,2173,2235,2297,2357,2416,2474,2530,2584,2636,2685,2733,2777,2819,2857,
2892,2924,2953,2978,2999,3017,3030,3040,3046,3048,3046,3040,3030,3017,2999,2978,
2953,2924,2892,2857,2819,2777,2733,2685,2636,2584,2530,2474,2416,2357,2297,2235,
2173,2111,2048,1985,1923,1861,1799,1739,1680,1622,1566,1512,1460,1411,1363,1319,
1277,1239,1204,1172,1143,1118,1097,1079,1066,1056,1050,1048,1050,1056,1066,1079,
1097,1118,1143,1172,1204,1239,1277,1319,1363,1411,1460,1512,1566,1622,1680,1739,
1799,1861,1923,1985};
//宏定义，最后的读SSPBUF是一定要的!
#define SPI_WRITE(A) \
SSPBUF=A; \
while(STAT_BF==0); \
BUF=SSPBUF
void main(void)
{ unsigned int x;
TRISB=0b11111001;
CS=1;NOP();
LDAC=1;
TRISC=0b00010000; //RC3输出(SCK),RC4输入(SDI),RC5输出(SDO)
SSPEN=1; //SPI串口使能
CKP=1; //空闲时钟为高电平
SSPM3=0;
SSPM2=0;
SSPM1=0;
SSPM0=0; //SPI主控模式,时钟为Fosc/4
STAT_SMP=1; //在数据输出时间的末端采样输入数据
STAT_CKE=0; //在SCK上升沿传输数据
PR2=99; //按照计算，每20us中断一次
T2CON=0b00000100;
N=0;
TMR2IE=1; //允许TMR2中断
PEIE=1;
GIE=1;
while(1);
}
void interrupt INT_ISR(void)
{ unsigned int X;
char i,j;
if (TMR2IF==1)
{ TMR2IF=0;
X=SS[N++];
if (N>=nn)
N=0;
X+=0x7000; //HSDN=1，参考电压缓冲，放大倍数GA=1
CS=0; //片选有效
i=X>>8;
j=X;
SPI_WRITE(i); //输出命令的高8位
SPI_WRITE(j); //输出命令的低8位
LDAC=0;NOP(); //DA输出有效
LDAC=1;NOP();
CS=1;
}
}
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PIC16F877输出正弦波信号仿真及程序.rar
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