单片机的定时器实现led灯的定时一分钟的减亮渐灭 -

/*-----------------------------------------------
名称：定时器0
内容：通过定时让LED灯闪烁
------------------------------------------------*/
#include<stc15.h> //包含头文件，一般情况不需要改动，头文件包含特殊功能寄存器的定义
sbit LED0=P3^6;
sbit LED1=P3^7;
sbit LED2=P3^3;
sbit LED3=P1^1;
sbit LED4=P1^2;
sbit LED5=P1^3;
sbit LED6=P1^4;
sbit LED7=P1^5;
sbit key=P3^2;
bit t1, t2,sudu;
unsigned int CYCLE=1100,PWM_LOW=0,a,b;
void Delay(unsigned int t);
void delays(unsigned char cnt)
{
unsigned char i;
unsigned char j;
unsigned char k;
for(i=cnt;i>0;i--)
{
for(j=cnt;j>0;j--)
{
for(k=cnt;k>0;k--);
}
}
}
/*------------------------------------------------
定时器初始化子程序
------------------------------------------------*/
void Init_Timer0(void)
{
TMOD |= 0x01; //使用模式1，16位定时器，使用"|"符号可以在使用多个定时器时不受影响
TH0=0x3c; //给定初值，这里使用定时器最大值从0开始计数一直到65535溢出
TL0=0xb0;
EA=1; //总中断打开
ET0=1; //定时器中断打开
TR0=1; //定时器开关打开
}
void paomadeng(void)
{
LED0=1;
Delay(700);
for(PWM_LOW=CYCLE-1;PWM_LOW>0;PWM_LOW--)
{
LED0=1;
Delay(PWM_LOW);
LED0=0;
Delay(CYCLE-PWM_LOW);
}
LED1=1;
Delay(700);
for(PWM_LOW=CYCLE-1;PWM_LOW>0;PWM_LOW--)
{
LED1=1;
Delay(PWM_LOW);
LED1=0;
Delay(CYCLE-PWM_LOW);
}
LED2=1;
Delay(700);
for(PWM_LOW=CYCLE-1;PWM_LOW>0;PWM_LOW--)
{
LED2=1;
Delay(PWM_LOW);
LED2=0;
Delay(CYCLE-PWM_LOW);
}
delays(7000);
LED2=0;
Delay(700);
for(PWM_LOW=1;PWM_LOW<CYCLE;PWM_LOW++)
{
LED2=1;
Delay(PWM_LOW);
LED2=0;
Delay(CYCLE-PWM_LOW);
}
LED2=1;
LED1=0;
Delay(700);
for(PWM_LOW=1;PWM_LOW<CYCLE;PWM_LOW++)
{
LED1=1;
Delay(PWM_LOW);
LED1=0;
Delay(CYCLE-PWM_LOW);
}
LED2=1;
LED1=1;
LED0=0;
Delay(700);
for(PWM_LOW=1;PWM_LOW<CYCLE;PWM_LOW++)
{
LED0=1;
Delay(PWM_LOW);
LED0=0;
Delay(CYCLE-PWM_LOW);
}
LED0=1;
}
/*------------------------------------------------
主程序
------------------------------------------------*/
main()
{
a=0;
Init_Timer0();
while(1)
{
if(a==1119)
{
paomadeng();
a=0;
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