高电平点亮流水灯
流水灯的电路图
#include<reg51.h>
void delay(unsigned int time)
{
unsigned char t;
for(; time > 0;time--)
for(t = 125; t > 0; t--);
}
void main(void)
{
unsigned char a = 0x01;
while(1)
{
if( a == 0x00)
a = 0x01; //注意高位溢出情况，若溢出则恢复
P2 = a;
a = a << 1; //循环点亮
delay(1000);
}
}
将流水灯逆序反复点亮
#include<reg51.h>
void delay(unsigned int time)
{
unsigned char t;
for(; time > 0;time--)
for(t = 125; t > 0; t--);
}
void main()
{
unsigned char a = 0x01;
unsigned char true = 1;
while(1)
{ while(true)
{
P2 = a;
a = a << 1;
delay(1000);
if(a == 0x00)
{
a = 0x80;
true = 0;
}
}
true = 1;
while(true)
{
P2 = a;
a = a >> 1;
delay(1000);
if(a == 0x00)
{
a = 0x01;
true = 0;
}
}
true = 1;
}
}
（优化过后）
#include<reg51.h>
void delay(unsigned int time)
{
unsigned char t;
for(; time > 0;time--)
for(t = 125; t > 0; t--);
}
void main(void)
{
unsigned char t;
while(1)
{
P2 = 0x01;
for(t = 0;t < 8;t++)
{
delay(1000);
P2 = P2 << 1;
}
P2 = 0x80;
for(t = 0;t < 8;t++)
{
delay(1000);
P2 = P2 >> 1;
}
}
}
