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程序如下,可以变亮变暗调节,问题是刚开始二极管总有一点光亮,不是全暗。不知是为什么
#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; // 计算1ms定时器计数=11059200 / 12/1000=921 1ms内调节PWM占空比
void ConfigPWM( );
void ConfigTimer1( );
void zhongjian(unsigned int dc);
void main()
{
EA = 1; //开总中断
zhongjian( dc);
ConfigPWM( ); //配置并启动PWM
ConfigTimer1( ); //每50ms增加或减少一次
while (1);
}
void ConfigTimer1( )
{
TMOD &= 0x0F; //清零T1的控制位
TMOD |= 0x10; //配置T1为模式1
TH1 = 0x3c; //加载T1重载值
TL1 = 0x11;
ET1 = 1; //使能T1中断
TR1 = 1; //启动T1
}
void ConfigPWM( )
{
TMOD &= 0xF0; //清零T0的控制位
TMOD |= 0x01; //配置T0为模式1
TH0 = HighRH; //加载T0重载值
TL0 = HighRL;
ET0 = 1; //使能T0中断
TR0 = 1; //启动T0
PWMOUT = 1; //输出高电平
}
void zhongjian(unsigned int dc)
{
unsigned int high, low;
high = dc; //计算高电平所需的计数值
low = 922 - high; //计算低电平所需的计数值
high = 65536 - high ; //计算高电平的定时器重载值并补偿中断延时
low = 65536 - low ; //计算低电平的定时器重载值并补偿中断延时
HighRH = (unsigned char)(high>>8); //高电平重载值拆分为高低字节
HighRL = (unsigned char)high;
LowRH = (unsigned char)(low>>8); //低电平重载值拆分为高低字节
LowRL = (unsigned char)low;
}
void InterruptTimer0() interrupt 1
{
if (PWMOUT == 1) //当前输出为高电平时,装载低电平值并输出低电平
{
TH0 = LowRH;
TL0 = LowRL;
PWMOUT = 0;
}
else //当前输出为低电平时,装载高电平值并输出高电平
{
TH0 = HighRH;
TL0 = HighRL;
PWMOUT = 1;
}
}
void InterruptTimer1() interrupt 3 //每50ms增加或减少一次内调节PWM占空比
{
static unsigned int index = 921;
TH1 = 0x3c; //加载T1重载值
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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