函数波形发生器（四种波形）

#include"reg51.h" #include"intrins.h" #define unchar unsigned char unchar code tab[128]={ 64,67,70,73,76,79,82,85,88,91,94,96,99,102,104,106, 109,111,113,115,117,118,120,121,123,124,125,126,126, 127,127,127,127,127,127,127,126,126,125,124,123,121, 120,118,117,115,113,111,109,106,104,102,99,96,94,91, 88,85,82,79,76,73,70,67,64,60,57,54,51,48,45,42,39, 36,33,31,28,25,23,21,18,16,14,12,10,9,7,6,4,3,2,1, 1,0,0,0,0,0,0,0,1,1,2,3,4,6,7,9,10,12,14,16,18,21,23, 25,28,31,33,36,39,42,45,48,51,54,57,60}; unchar mode=0,freq=40,fu=0; int zk=0; void delay(int n) //10us延时 {do { _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); } while(--n); } void df(int n) //延时 {do { _nop_(); _nop_(); } while(--n); } void key(); void sq() //方波 {while(mode==0) {P0=fu; df(10*freq+zk); P0=0xff-fu; df(10*freq-zk);} key();} void ju() //锯齿波 {unchar i; while(mode==1) {for(i=0;i<255-fu;i++) {P0=i; delay(freq);}} key();} void san() //三角波 {unchar i; while (mode==3) {for(i=0;i<255-fu;i++) {P0=i; delay(freq);} for(i=255-fu;i>0;i--) {P0=i; delay(freq);}} key();} void sin() //正弦波 {unchar i; while(mode==2) {if(++i==128)i=0; P0=tab[i]; delay(freq);} key();} void key() //模式识别 {if(mode==0) sq(); if(mode==1) ju(); if(mode==2) sin(); if(mode==3) san();} void main() {IT0=1; IE=0x81; sq();} void zhong() interrupt 0 {unchar i; i=P1; if(i==0xfe) if(mode<3) mode++; else mode=0; if(i==0xfd) if (freq<75) freq=freq+5; else freq==0; if(i==0xfb) if(freq>5) freq=freq-5; else freq==80; if(i==0xf7&&mode==0) if(10*freq-zk>0) zk=zk+30; else zk=-10*freq; if(i==0xef) fu=fu-10; if(i==0xdf) fu=fu+10; }