51单片机PWM产生程序（256精度）带按键调节 -

////****************************************************************************//
#include <STC12C5A60S2.H>
#include <intrins.h>
#define uchar unsigned char
#define uint unsigned int
/*******PWM模式变量更改**********/
//#define DR_50 0x7f //50%占空比
//#define DR_10 0x19 //10%占空比
///*******时钟源选择*******/
#define CLK_4 0x02// 0x08 //Sysclk
//********模式选择********/
#define P_model 0x42 //无中断PWM模式
sbit keyup=P3^4; //步进加端口位定义
sbit keydown=P3^5; //步进减端口位定义
sbit keyup1=P3^6; //步进1加端口位定义
sbit keydown1=P3^7; //步进1减端口位定义
uchar num=127;
uchar num1=127;
/*****函数声明*****/
void PP_init(void); //PWM模式初始化
void delay(int); //延时函数声明
// P_model初始化 //
//********************************//
void PP_init(void)
{
CMOD = CLK_4; //时钟源为Sysclk
CCAPM0 = P_model; //无中断PWM模式
// CCAP0L = DR_10; //%50占空比
CCAP0H = 0x7f; //当CL值大于CCAP0L时输出为高,反之输出为低
//当CL溢出时CCAP0H的值装载到CCAP0L中
CCAPM1 = P_model; //无中断PWM模式
//CCAP1L = DR_10; //%50占空比
CCAP1H = 0x7f; //当CL值大于CCAP0L时输出为高,反之输出为低
//当CL溢出时CCAP0H的值装载到CCAP0L中
CR = 1; //开启PCA计数器
//当不使用定时0溢出为时钟源时,PWM输出的频率=PCA的时钟源/256
//使用定时器溢出的时钟源时,可设定定时器的值对输出频率的改变
//分频为0-256分频
}
void delay(int x) //12M晶振，约1ms延时函数
{
int i;
for(;x>0;x--)
for(i=0;i<123;i++)
;
}
/////////////////////
uchar code byte[]={ 0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,
0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f,
0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,0x29,0x2a,0x2b,0x2c,0x2d,0x2e,0x2f,
0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x3a,0x3b,0x3c,0x3d,0x3e,0x3f,
0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f,
0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5a,0x5b,0x5c,0x5d,0x5e,0x5f,
0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x6b,0x6c,0x6d,0x6e,0x6f,
0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7a,0x7b,0x7c,0x7d,0x7e,0x7f,
0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87,0x88,0x89,0x8a,0x8b,0x8c,0x8d,0x8e,0x8f,
0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9a,0x9b,0x9c,0x9d,0x9e,0x9f,
0xa0,0xa1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,0xa8,0xa9,0xaa,0xab,0xac,0xad,0xae,0xaf,
0xb0,0xb1,0xb2,0xb3,0xb4,0xb5,0xb6,0xb7,0xb8,0xb9,0xba,0xbb,0xbc,0xbd,0xbe,0xbf,
0xc0,0xc1,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xcb,0xcc,0xcd,0xce,0xcf,
0xd0,0xd1,0xd2,0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xdb,0xdc,0xdd,0xde,0xdf,
0xe0,0xe1,0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,0xeb,0xec,0xed,0xee,0xef,
0xf0,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfe,0xff,
};//DA转换数据
void main()
{
PP_init();
while(1)
{
if(keyup==0) //步进加端口为低电平，
{
delay(10); //稍作延时，消抖，
if(keyup==0) //步进加端口依然为低电平，说明的确是被按下，
{
if(num==255) //执行电压DA转换数值步进增加一
num=0;
else
num++;
}
while(keyup==0); //防止按死语句
}
if(keydown==0) //步进减端口为低电平，
{
delay(10); //稍作延时，消抖，
if(keydown==0) //步进减端口依然为低电平，说明的确是被按下，
{
if(num==0) //执行电压DA转换数值步进减一
num=255;
else
num--;
}
while(keydown==0); //防止按死语句
}
CCAP0H=byte[num]; //给DA一个数值，转化成相应的电压值
delay(10);
//////////////////////////////
if(keyup1==0) //步进加端口为低电平，
{
delay(10); //稍作延时，消抖，
if(keyup1==0) //步进加端口依然为低电平，说明的确是被按下，
{
if(num1==255) //执行电压DA转换数值步进增加一
num1=0;
else
num1++;
}
while(keyup1==0); //防止按死语句
}
if(keydown1==0) //步进减端口为低电平，
{
delay(10); //稍作延时，消抖，
if(keydown1==0) //步进减端口依然为低电平，说明的确是被按下，
{
if(num1==0) //执行电压DA转换数值步进减一
num1=255;
else
num1--;
}
while(keydown1==0); //防止按死语句
}
CCAP1H=byte[num1]; //给DA一个数值，转化成相应的电压值
delay(10);
}
}

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