PWM.rar_STC_STC PWM_pwm_stc pwm_stc占空比可调

/********************PWM测试模块****************/ /**************波特率1200，晶振12MHZ************/ /**************上位机平台STC编程环境************/ /*****************P3.7输出PWM信号***************/ /****************MCU：STC12C5052AD**************/ //1.PWM的频率是PCA的时钟输入源频率/256,PCA时钟输入源可以从4种中选择一种: // // Fosc/12(CPS0=0,CPS1=0),Fosc/2(CPS0=1,CPS1=0), // // 定时器0的溢出(CPS0=0,CPS1=1),ECI/P3.4输入(CPS0=1,CPS1=1) // //2.举例:要求PWM输出频率为38KHz,选Fosc/2为PCA/PWM时钟输入源,求出Fosc的值 // // 由计算公式38000=Fosc/2/256,得到外部时钟频率Fosc=3800*256*2=19,456,000 // // 如果要实现可调频率的PWM输出,可选择定时器0的溢出或者ECI脚的输入作为PCA/PWM的时钟输入源// //sfr CCON = 0xD8; //sfr CMOD = 0xD9; //sfr CCAP0L = 0xEA; //sfr CCAP0H = 0xFA; //sfr CCAPM0 = 0xDA; //sfr CCAPM1 = 0xDB; //sbit CR = 0xDE; #include <C:\WAVE6000\COMP51V6\STC12C2052AD.H> #include <C:\WAVE6000\COMP51V6\Intrins.h> #include <C:\WAVE6000\COMP51V6\Stdio.h> #include <C:\WAVE6000\COMP51V6\Math.h> #include <C:\WAVE6000\COMP51V6\String.h> #define uchar unsigned char #define uint unsigned int #define ulong unsigned long sbit P1_1 = P1^1; sbit P1_3 = P1^3; sbit P1_4 = P1^4; sbit P1_7 = P1^7; void delay(ulong i) { ulong j; for(j=0;j<i;j++) _nop_(); } void main(void) { // CMOD = 0x02; //CPS0=1 setup PCA timer CMOD = 0x04; CL = 0x00; CH = 0x00; CCAP0L = 0x80; //set the initial value same as CCAP0H CCAP0H = 0x80; //25% Duty Cycle CCAPM0 = 0x42; //0100,0010 Setup PCA module 0 in PWM mode //EC0M0=1,PWM0=1 CR = 1; //Start PCA Timer TMOD = 0x02; TH0 = 0x80; TL0 = 0x80; TR0 = 1; while(1) { if(P1_3==0) { delay(5000); if(P1_3==0) { if(CCAP0L<0xff) { CCAP0L++; CCAP0H++; } } } if(P1_4==0) { delay(5000); if(P1_4==0) { if(CCAP0L>0) { CCAP0L--; CCAP0H--; } } } if(P1_7==0) { delay(5000);delay(5000);delay(5000); if(P1_7==0) { if(TH0<0xFF) { TH0++; TL0++; } } } if(P1_1==0) { delay(5000);delay(5000);delay(5000); if(P1_1==0) { if(TH0>0) { TH0--; TL0--; } } } } }