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程序如下，可以變亮變暗調(diào)節(jié)，問題是剛開始二極管總有一點光亮，不是全暗。不知是為什么
#include <reg52.h>
#include"intrins.h"
sbit PWMOUT = P0^0;
sbit bianan = P3^2;
sbit bianliang = P3^3;
unsigned char HighRH = 0;
unsigned char HighRL = 0;
unsigned char LowRH = 0;
unsigned char LowRL = 0;
unsigned int dc=921; // 計算1ms定時器計數(shù)=11059200 / 12/1000=921 1ms內(nèi)調(diào)節(jié)PWM占空比
void ConfigPWM( );
void ConfigTimer1( );
void zhongjian(unsigned int dc);
void main()
{
EA = 1; //開總中斷
zhongjian( dc);
ConfigPWM( ); //配置并啟動PWM
ConfigTimer1( ); //每50ms增加或減少一次
while (1);
}
void ConfigTimer1( )
{
TMOD &= 0x0F; //清零T1的控制位
TMOD |= 0x10; //配置T1為模式1
TH1 = 0x3c; //加載T1重載值
TL1 = 0x11;
ET1 = 1; //使能T1中斷
TR1 = 1; //啟動T1
}
void ConfigPWM( )
{
TMOD &= 0xF0; //清零T0的控制位
TMOD |= 0x01; //配置T0為模式1
TH0 = HighRH; //加載T0重載值
TL0 = HighRL;
ET0 = 1; //使能T0中斷
TR0 = 1; //啟動T0
PWMOUT = 1; //輸出高電平
}
void zhongjian(unsigned int dc)
{
unsigned int high, low;
high = dc; //計算高電平所需的計數(shù)值
low = 922 - high; //計算低電平所需的計數(shù)值
high = 65536 - high ; //計算高電平的定時器重載值并補償中斷延時
low = 65536 - low ; //計算低電平的定時器重載值并補償中斷延時
HighRH = (unsigned char)(high>>8); //高電平重載值拆分為高低字節(jié)
HighRL = (unsigned char)high;
LowRH = (unsigned char)(low>>8); //低電平重載值拆分為高低字節(jié)
LowRL = (unsigned char)low;
}
void InterruptTimer0() interrupt 1
{
if (PWMOUT == 1) //當前輸出為高電平時，裝載低電平值并輸出低電平
{
TH0 = LowRH;
TL0 = LowRL;
PWMOUT = 0;
}
else //當前輸出為低電平時，裝載高電平值并輸出高電平
{
TH0 = HighRH;
TL0 = HighRL;
PWMOUT = 1;
}
}
void InterruptTimer1() interrupt 3 //每50ms增加或減少一次內(nèi)調(diào)節(jié)PWM占空比
{
static unsigned int index = 921;
TH1 = 0x3c; //加載T1重載值
TL1 = 0x11;
if(bianan == 0) {index++; if(index>= 921) {index = 921;} }
if(bianliang == 0) {index--; if(index<= 2) {index = 1;}}
zhongjian(index);
}
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