Hello

The program written below should work as follows : ... switches

are connected to PORT 1 and LED;s are connected to PORT 2 ...

on hitting any switch the corresponding LED should bre ON

ie ... if we press switch 0 LED 0 should ON ... if agin we

press switch 0 then the LED 0 should become OFF ..

The problem I am encountering is the switches are pressed

more then twice to be operated ie. switch is pressed 2 times

for the same function to be happened ...

If some body can help me to get rid of this probs ... then I

will be very thankfull ...

DELAY_HIGH EQU 003H

DELAY_LOW EQU 018H

FLAG_0 EQU 031H
FLAG_1 EQU 032H
FLAG_2 EQU 033H
FLAG_3 EQU 034H
FLAG_4 EQU 035H
FLAG_5 EQU 036H
FLAG_6 EQU 037H
FLAG_7 EQU 038H
FLAG_INVALIDKEY EQU 039H
FLAG_PUSH EQU 040H
NEWKEY EQU 041H

ORG 000H
MOV SP,#050H
LJMP START

ORG 000BH
ACALL INTERRUPT_0
RETI

ORG 001BH
INTERRUPT_1:

PUSH ACC
PUSH PSW
CLR TR1
MOV PSW,#00H
ACALL KEYPRESSED
JNZ CALCULATE
JMP ALTER

CALCULATE:

ACALL KEYPRESSED
JZ ALTER
ACALL CONVERT
JBC FLAG_INVALIDKEY,ALTER
ACALL TIMER_0
POP ACC
POP PSW
RETI

ALTER:

CLR FLAG_PUSH

AGAIN:

ACALL TIMER_1
POP PSW
POP ACC
RETI

INTERRUPT_0:

PUSH ACC
PUSH PSW
MOV PSW,#00H
CLR TR0
ACALL KEYPRESSED
JZ ALTER_1
ACALL CONVERT
JBC FLAG_INVALIDKEY,ALTER_1
JB FLAG_PUSH,COMPARE
SETB FLAG_PUSH
MOV NEWKEY,A
JMP HOME

COMPARE:

CJNE A,NEWKEY,CLEAR
JMP AGAIN_1

HOME:

JB ACC.0,COOL_0
JB ACC.1,COOL_1
JB ACC.2,COOL_2
JB ACC.3,COOL_3
JB ACC.4,COOL_4
JB ACC.5,COOL_5
JB ACC.6,COOL_6
JB ACC.7,COOL_7

CLEAR:

CLR FLAG_PUSH
JMP HOME

WORLD:

MOV R0,A
MOV A,P2
ORL A,R0
XRL A,R0
MOV P2,A
JMP STATUS

UNIVERSE:

ORL A,P2
MOV P2,A
JMP AGAIN_1

ALTER_1:

CLR FLAG_PUSH

AGAIN_1:

ACALL TIMER_1
POP PSW
POP ACC
RET

COOL_0:

JB FLAG_0,WORLD
SETB FLAG_0
JMP UNIVERSE

COOL_1:

JB FLAG_1,WORLD
SETB FLAG_1
JMP UNIVERSE

COOL_2:

JB FLAG_2,WORLD
SETB FLAG_2
JMP UNIVERSE

COOL_3:

JB FLAG_3,WORLD
SETB FLAG_3
JMP UNIVERSE

COOL_4:

JB FLAG_4,WORLD
SETB FLAG_4
JMP UNIVERSE

COOL_5:

JB FLAG_5,WORLD
SETB FLAG_5
JMP UNIVERSE

COOL_6:

JB FLAG_6,WORLD
SETB FLAG_6
JMP UNIVERSE

COOL_7:

JB FLAG_7,WORLD
SETB FLAG_7
JMP UNIVERSE

STATUS:

JBC FLAG_0,AGAIN_1
JBC FLAG_1,AGAIN_1
JBC FLAG_2,AGAIN_1
JBC FLAG_3,AGAIN_1
JBC FLAG_4,AGAIN_1
JBC FLAG_5,AGAIN_1
JBC FLAG_6,AGAIN_1
JBC FLAG_7,AGAIN_1

KEYPRESSED:

MOV P1,#0FFH
MOV A,P1
CPL A
RET

START:

MOV IE,#08AH
MOV TMOD,#011H
MOV P1,#0FFH
MOV P2,#00H
MOV R0,#00H
MOV R7,#00H
CLR FLAG_0
CLR FLAG_1
CLR FLAG_2
CLR FLAG_3
CLR FLAG_4
CLR FLAG_5
CLR FLAG_6
CLR FLAG_7
ACALL TIMER_1

KEY:

MOV P1,#0FFH
MOV A,P1
CPL A
JMP KEY

TIMER_0:

;MOV TL0,#070H
;MOV TH0,#0DAH
MOV TL0,#DELAY_LOW
MOV TH0,#DELAY_HIGH
SETB TR0
RET

TIMER_1:

MOV TL1,#DELAY_LOW
MOV TH1,#DELAY_HIGH
SETB TR1
RET

CONVERT:

CLR FLAG_INVALIDKEY

CJNE A,#01H,SECOND
RET

SECOND:

CJNE A,#02H,THIRD
RET

THIRD:

CJNE A,#04H,FOURTH
RET

FOURTH:

CJNE A,#08H,FIVE
RET

FIVE:

CJNE A,#010H,SIX
RET

SIX:

CJNE A,#020H,SEVEN
RET

SEVEN:

CJNE A,#040H,EIGHT
RET

EIGHT:

CJNE A,#080H,BAD
RET

BAD:

SETB FLAG_INVALIDKEY
RET


;**************************************************************************************************
END

regards
Arvind Shrivastava ...