bb1.c

关于51的各种例子,仔细学习后会有很大的作用

#include<AT89x51.H>
unsigned char t5hz;
unsigned char t7hz;
unsigned int ucount;
bit stop;
bit flag;
main()
{
unsigned char i,j;
TMOD=0x02;
TH0=0x06;
TL0=0x06;
EA=1;
ET0=1;
while(1)
{
if(P3_2==0)
{
for(i=0;i<20;i++)
for(j=0;j<248;j++);
if(P3_2==0)
{
t5hz=0;
t7hz=0;
stop=0;
flag=0;
TR0=1;
while(stop==0);
}
}
}
}
void timerr(void) interrupt 1 
{
ucount++;
if(ucount==2000)
{
ucount=0;
if(flag==0)
flag=~flag;
else
{
stop=1;
TR0=0;
}
}
if(flag==0)
{
t7hz++;
if(t7hz==3)
{
t7hz=0;
P0_7=~P0_7;
}
}
else
{
t5hz++;
if(t5hz==4)
{
t5hz=0;
P0_7=~P0_7;
}
}
}