Question

单片机LED灯动态

89C51 P1口做输出口，接八只发光二极管，编写程序，使发光二极管4盏循环点亮

Answer 1

我只学过汇编！下面有两种效果。
第一种：
start:mov a,#0f0h
mov p1,a
call delay
mov a,#0fh
mov p1,a
call delay
sjmp start
delay:mov r7,#20
d1:mov r6,#200
d2:mov r5,#123
nop
djnz r5,$
djnz r6,d2
djnz r7,d1
ret
end
第二种：
start:mov a,#055h
mov p1,a
call delay
mov a,#0aah
mov p1,a
call delay
sjmp start
delay:mov r7,#20
d1:mov r6,#200
d2:mov r5,#123
nop
djnz r5,$
djnz r6,d2
djnz r7,d1
ret
end

Answer 2

下列程序，有四个LED同时发光，使用PROTUSE验证了。

#include<reg52.h>
#include<intrins.h>
#define uchar unsigned char
#define uint unsigned int

uchar x;

void main()
{
TMOD = 0x01;
TH0 = (65536 - 50000) / 256;
TL0 = (65536 - 50000) % 256;
TR0 = 1;
ET0 = 1;
EA = 1;
x = 0;
P1 = 0x0F;
while(1);
}

void time0() interrupt 1
{
uchar a;
TH0 = (65536 - 50000) / 256;
TL0 = (65536 - 50000) % 256;
x++;
if(x == 20) {
x = 0;
a = P1;
a = _crol_(a, 1);
P1 = a;
}
}

Answer 3

# include<reg51.h>
void delay()
{
unsigned int i;
for(i=0;i<20000;i++);
}
void main()
{
unsigned char index;
unsigned char LED;

while(1)
{
LED=0x01;
for(index=0;index<4;index++){
P1=LED;
LED<<=0x01;
delay();
}
}
}