按键和定时器中断综合应用-秒表计时器

& INT1按键中断INT0#

和T0中断的综合应用

‐简易秒表计时器

范例1：汇编源代码

范例2：C51源代码

P7 EQU 0F8H ORG 0100H

#60H P6 EQU 0E8H

D1 EQU 0FEH //数码管个位EQU 0FDH MAIN: MOV SP ,#60H //设置堆栈

MOV P2,#0FFH //关P2口LED MOV TMOD,#00H D2 //十位D3 EQU 0FBH // 百位

VARX DATA 30H //计数变量DATA 31H MOV TH0,#4BH

MOV TL0,#0FDH //设置T0MOV R7,#20MOV VARX,#0 //置计数变量0DIG1 //BCD 个位DIG2 DATA 32H //BCD 十位DIG3 DATA 33H //BCD ,SETB ET0SETB EX0SETB IT0//百位ORG 0000H LJMP MAIN SETB EX1SETB IT1

SETB EA //允许相关中断

ORG 0003H

LJMP KY1INT //KY1中断ORG 000BH

LJMP T0INT //T0中断ORG 0013H

KY2INT //KY2LJMP 中断

CONV:

MOV A,VARX //读计数变量MOV A,DIG2 //读十位BCD MOV B,#100DIV AB DIG3A MOVC A,@A+DPTR MOV P7,A P6#D2//MOV DIG3,A MOV A,B MOV B,#10MOV P6,#D2 查表送显示ACALL DELAY //扫描延时A,DIG3//DIV AB

MOV DIG2,A DIG1B MOV 读百位BCD MOVC A,@A+DPTR MOV P7,A

MOV DIG1,B //转换为3位BCD DISP: MOV A,DIG1 //读个位BCD

MOV DPTR,#SEGTBL MOV P6,#D3 //查表送显示ACALL DELAY

CONV //MOVC A,@A+DPTR MOV P7,A

P6,#D1//LJMP 返回读取VARX

MOV 查表送显示

ACALL DELAY //扫描延时

•//软件延时程序段•R1#100T0INT: DJNZ R7,BACK

R7#20DELAY: MOV R1,#100•DL1: MOV R2,#10R2DL2

MOV R7,#20CPL P2.0INC VARX •DL2: DJNZ R2,DL2•DJNZ R1,DL1BACK: RETI

//•RET

KY1INT:

共阳型数码管字符//0‐9的的段码表

ORG 0200H

0C0H 0F9H 0A4H 0B0H

JNB TR0,RUNT0 //若未启动TR0,则启动计数

SEGTBL: DB 0C0H,0F9H,0A4H,0B0H DB 99H,92H,82H,0F8H,80H,90H

CLR TR0 //否则停止计数RETI

RUNT0: SETB TR0

RETI

KY2INT: MOV VARX,#0 //将VARX 清零

RETI

范例2：C51的程序实现

•#include "stc15.h"

•#include intrins.h

"intrins h"

•typedef unsigned char u8;

•u8 varx;;

•#define D1 0xFE

•#define D2 0xFD

•#define D3 0xFB

•u8 dig1,dig2,dig3;

•u8 count;

8t

•void dly20ms();

•const u8 code Seg8[10] =

{0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};•u8 *ptr;

•void main()

•{

•P2 = 0xFF;•varx= 0;

•ptr= Seg8;•count = 20;•TMOD = 0x00;

TH0 19453/256;•=

•TL0 = 19453%256;•ET0 = 1;;

•EX0 = 1;

•IT0 = 1;;

•EX1 = 1;

•IT1 = 1;

•EA = 1;

•while(1)

•{

•dig3 = varx/100;•dig2 = (varx%100)/10;•dig1 = (varx%100)%10;•P7 = *(ptr+dig1);

•P6 = D1;

•dly20ms();

•P7 = *(ptr+dig2);

•P6 = D2;

•dly20ms();

•=*(ptr+dig3);

P7 (ptr dig3);

•P6 = D3;

•dly20ms();

•}

•

•}

•void ky1int() interrupt 0•{

•if(TR0 == 0 ) TR0 = 1;•else TR0 =0;

•}

•void ky2int() interrupt 2•0;}

{ varx=

•void T0int() interrupt 1•{

()

•if(count‐‐!=0) return;•else

•{

•P20 ^= 1;

•count = 20;•varx++;

•}

•}