org 0

num1 EQU 30H ;first digit in number 1 in loc 30h

num2 EQU 31H ;second digit in number 1 in loc 31h
num3 EQU 32H ;second digit in number 1 in loc 31h
op EQU 33H ; operation in loc 32h
num4 EQU 34H ;first digit in number 2 in loc 30h
num5 EQU 35H ;second digit in number 2 in loc 31h
num6 EQU 36H ;second digit in number 2 in loc 31h

RS bit P2.4
RW bit P2.5
E bit P2.6
commandOrData EQU P3
;keyboard subroutine. This program sends the ASCII
;code for pressed key to P0.1
;P1.0-P1.3 connected to rows, P2.0-P2.3 to column
MOV P2,#0FFH ;make P2 an input port
Lcall lcdInitial ;on CURSOR of lcd

main:
Lcall waitForKey
mov A,20H
CJNE A,#'c',w1 ;c for clear in key pad
lcall cleaar
ljmp main
w1:Lcall lcdWrite ;20H
Lcall DELAY
Mov num1,20H ;first digit of num1

Lcall waitForKey
Mov A,20H
CJNE A,#'c',w2
lcall cleaar
ljmp main
w2:
Lcall lcdWrite ;20H
Lcall DELAY
Mov num2,20H ;second digit of num1

Lcall waitForKey
Mov A,20H
CJNE A,#'c',w3
lcall cleaar
ljmp main
w3:
Lcall lcdWrite ;20H
Lcall DELAY
Mov num3,20H ;third digit of num1

Lcall waitForKey
mov A,20H
CJNE A,#'c',oper
lcall cleaar
ljmp main
oper:Lcall lcdWrite ;20H
Lcall DELAY
Mov op,20H ;operation
 Lcall waitForKey
mov A,20H
CJNE A,#'c',w4
lcall cleaar
ljmp main
w4:Lcall lcdWrite ;20H
Lcall DELAY
Mov num4,20H ;first digit of num2

Lcall waitForKey
Mov A,20H
CJNE A,#'c',w5
lcall cleaar
ljmp main
w5:
Lcall lcdWrite ;20H
Lcall DELAY
Mov num5,20H ;second digit of num2

Lcall waitForKey
Mov A,20H
CJNE A,#'c',w6
lcall cleaar
ljmp main
w6:
Lcall lcdWrite ;20H
Lcall DELAY
Mov num6,20H ;third digit of num2

Process:
ANl num1,#0FH
ANl num2,#0FH
ANl num3,#0FH
ANl num4,#0FH
ANl num5,#0FH
ANl num6,#0FH
mov A,num1
mov b,#100
mul Ab
mov r6,A
mov A,num2
mov b,#10
mul Ab
add A,r6
add A,num3
mov num1,A ; the first number in 3 digit in decimal

mov A,num4
mov b,#100
mul Ab
mov r7,A
mov A,num5
mov b,#10
mul Ab
add A,r7
add A,num3
mov num2,A ;the second number in 3 digit in decimal
 mov A,op
N4:CJNE A, #'+',N1
lcall equal ; put(=)
lcall sum ;put the result of sum
Ljmp main
N1:CJNE A, #'-',N2
lcall equal ; put(=)
lcall sub ;put the result of sub
Ljmp main
N2:CJNE A, #'*', N3
lcall equal ; put(=)
lcall prod ;put the result of prod
Ljmp main
N3:CJNE A, #'/', N4
lcall equal ; put(=)
lcall divid ;put the result of divid
Ljmp main

sum:
Mov A,num1
ADD A,num2
mov b,#100
div Ab
ORL A,#30H ; ascii
Mov 20H,A
Lcall lcdWrite
Lcall DELAY
mov A,b
mov b,#10
div Ab
ORL A,#30H
Mov 20H,A
Lcall lcdWrite
Lcall DELAY
ORL b,#30H
Mov 20H,b
Lcall lcdWrite
Lcall DELAY
lcall donee
Lcall DELAY
lcall cleaar
Lcall DELAY
ljmp main

sub:
Mov A,num1
subb A,num2
mov b,#100
div Ab
ORL A,#30H ; ascii
Mov 20H,A
Lcall lcdWrite
Lcall DELAY
mov A,b
mov b,#10
div Ab
ORL A,#30H
 Mov 20H,A
Lcall lcdWrite
Lcall DELAY
ORL b,#30H
Mov 20H,b
Lcall lcdWrite
Lcall DELAY
lcall donee
Lcall DELAY
lcall cleaar
Lcall DELAY
ljmp main

prod:

mov A,num1
mov b,num2
mul Ab
mov b,#100
div Ab
ORL A,#30H ; ascii
Mov 20H,A
Lcall lcdWrite
Lcall DELAY
mov A,b
mov b,#10
div Ab
ORL A,#30H
Mov 20H,A
Lcall lcdWrite
Lcall DELAY
ORL b,#30H
Mov 20H,b
Lcall lcdWrite
Lcall DELAY
lcall donee
Lcall DELAY
lcall cleaar
Lcall DELAY
ljmp main

divid:

mov b,num2
mov A,b
CJNE A,#000H,dividd
lcall cleaar
Lcall DELAY
lcall erorrr
lcall cleaar
Lcall DELAY
ljmp main
dividd:
mov A,num1
div Ab
mov r2,b
mov b,#100
 div Ab
ORL A,#30H ; ascii
Mov 20H,A
Lcall lcdWrite
Lcall DELAY
mov A,b
mov b,#10
div Ab
ORL A,#30H
Mov 20H,A
Lcall lcdWrite
Lcall DELAY
ORL b,#30H
Mov 20H,b
Lcall lcdWrite
Lcall DELAY
mov A,r2
CJNE A,#000H,h
lcall donee
Lcall DELAY
lcall cleaar
Lcall DELAY
ret
h:
Mov 20H,#'.'
Lcall lcdWrite
Lcall DELAY
mov A,r2
mov b,#10
mul Ab
mov b,num2
div Ab
ORL A,#30H
Mov 20H,A
Lcall lcdWrite
Lcall DELAY
ret

equal:
Lcall waitForKey
Mov A,20H
q:cjne A,#'=' ,q
Lcall lcdWrite
Lcall DELAY
ret

donee:
mov dptr,#700H
ppack:mov A,#0
movc A,@A+dptr
jz ffinsh
mov 20H,A
Lcall lcdWrite
Lcall DELAY
inc dptr
sjmp ppack
ffinsh:ret
 org 700H
mmsg:db "done",0

cleaar:
Mov A,#01H
Lcall COMNWRT ;20H
Lcall DELAY
ret
erorrr:
lcall cleaar
mov 20H,#'e'
Lcall lcdWrite
Lcall DELAY
mov 20H,#'r'
Lcall lcdWrite
Lcall DELAY
mov 20H,#'r'
Lcall lcdWrite
Lcall DELAY
mov 20H,#'o'
Lcall lcdWrite
Lcall DELAY
mov 20H,#'r'
Lcall lcdWrite
Lcall DELAY
lcall cleaar
waitForKey:
K1: MOV P1,#0 ;ground all rows at once
MOV A,P2 ;read all col
;(ensure keys open)
ANL A,#00001111B ;masked unused bits
CJNE A,#00001111B,K1 ;till all keys release
;K2: LCALL DELAY ;call 20 msec delay
;MOV A,P2 ;see if any key is pressed
;ANL A,#00001111B ;mask unused bits
;CJNE A,#00001111B,OVER;key pressed, find row
;SJMP K2 ;check till key pressed
OVER: LCALL DELAY ;wait 20 msec debounce time
MOV A,P2 ;check key closure
ANL A,#00001111B ;mask unused bits
CJNE A,#00001111B,OVER1;key pressed, find row
SJMP over ;if none, keep polling

OVER1: MOV P1, #11111110B ;ground row 0

MOV A,P2 ;read all columns
ANL A,#00001111B ;mask unused bits
CJNE A,#00001111B,ROW_0 ;key row 0, find col.
MOV P1,#11111101B ;ground row 1
MOV A,P2 ;read all columns
ANL A,#00001111B ;mask unused bits
CJNE A,#00001111B,ROW_1 ;key row 1, find col.
MOV P1,#11111011B ;ground row 2
MOV A,P2 ;read all columns
ANL A,#00001111B ;mask unused bits
CJNE A,#00001111B,ROW_2 ;key row 2, find col.
MOV P1,#11110111B ;ground row 3
MOV A,P2 ;read all columns
ANL A,#00001111B ;mask unused bits
CJNE A,#00001111B,ROW_3 ;key row 3, find col.
LJMP over ;if none, false input, ;repeat

ROW_0: MOV DPTR,#KCODE0 ;set DPTR=start of row 0

SJMP FIND ;find col. Key belongs to
ROW_1: MOV DPTR,#KCODE1 ;set DPTR=start of row
SJMP FIND ;find col. Key belongs to
ROW_2: MOV DPTR,#KCODE2 ;set DPTR=start of row 2
SJMP FIND ;find col. Key belongs to
ROW_3: MOV DPTR,#KCODE3 ;set DPTR=start of row 3
FIND: RRC A ;see if any CY bit low
JNC MATCH ;if zero, get ASCII code
INC DPTR ;point to next col. addr
SJMP FIND ;keep searching
MATCH: CLR A ;set A=0 (match is found)
MOVC A,@A+DPTR ;get ASCII from table
MOV P3,A ;display pressed key
Mov 20H,A
;LCALL lcdWrite
;LCALL Delay
ret
; ASCII LOOK-UP TABLE FOR EACH ROW
ORG 300H
KCODE0: DB '/','9','8','7' ;ROW 0
KCODE1: DB '*','6','5','4' ;ROW 1
KCODE2: DB '-','3','2','1' ;ROW 2
KCODE3: DB '+','=','0','c' ;ROW 3

Delay:Mov R0,#255
here1:Mov R1,#255
here:DJNZ R1,here
DJNZ R0,here1
ret

DELAY1: Mov R1,#6

HERE3:MOV R3,#255 ;50 or higher for fast CPUs
HERE2: MOV R4,#255 ;R4 = 255
HERE4: DJNZ R4,HERE4 ;stay until R4 becomes 0
DJNZ R3, HERE2
DJNZ R1, HERE3
RET
org 200H
lcdInitial:MOV A,#38H ;INIT. LCD 2 LINES, 5X7 MATRIX
LCALL COMNWRT ;call command subroutine
LCALL DELAY ;give LCD some time
MOV A,#0EH ;display on, cursor on
LCALL COMNWRT ;call command subroutine
LCALL DELAY ;give LCD some time
ret

lcdWrite:
;MOV A,#01 ;clear LCD
;LCALL COMNWRT ;call command subroutine
;LCALL DELAY ;give LCD some time
MOV A,20H ;display letter N
LCALL DATAWRT ;call display subroutine
 LCALL DELAY ;give LCD some time
ret

COMNWRT: ;send command to LCD

MOV commandOrData,A ;copy reg A to port 1
CLR RS ;RS=0 for command
CLR RW ;R/W=0 for write
SETB E ;E=1 for high pulse
CLR E ;E=0 for H-to-L pulse
RET

DATAWRT: ;write data to LCD

MOV commandOrData,A ;copy reg A to port 1
SETB RS ;RS=1 for DATA
CLR RW;R/W=0 for write
SETB E ;E=1 for high pulse
CLR E ;E=0 for H-to-L pulse
RET

End