Question

求单片机程序:要求延时为1秒，采用定时器T1定时方式1实现50ms*20次中断

Answer 1

参考下面的程序：

Answer 2

#include "reg51.h"
uchar i=0;
uchar msflag=0;
void initTimer(void)
{
TMOD=0x10;
TH1=0x3c;
TL1=0xb0;
}

void timer1(void) interrupt3
{
TH1=0x3c;
TL1=0xb0;
//add your code here.
if(++i>20){ i = 0; msflag =1;}
}
void main(void)
{
initTimer();
TR1=1;
ET1=1;
//EA=1;
while(1)
{
if(msflag==1)

{ //1s到了

msflag =0;

}
}

Answer 3

假设：晶振=12M
ORG 0000H
LJMP MAIN
ORG 001BH
LJMP T1ISR
ORG 0030H
MAIN:
MOV TMOD,#10H

MOV TH1,#3CH

MOV TL1,#0B0H

SETB TR1

SETB ET1

SETB EA

MOV R2,#20

SJMP $

T1ISR:
CLR TR1

MOV TH1,#3CH

MOV TL1,#0B0H

SETB TR1

DJNZ R2,T1E

MOV R2,#20

CPL P1.0

T1E:
RETI

END