key.asm

基于Multisim9的电子系统设计、仿真与综合应用（实例源文件）

$MOD52     ; This includes 8052 definitions for the metalink assembler
;
; Variables
;

NUM1L		DATA	020H	; low byte of first operand
NUM1H		DATA	021H	; high byte of first operand
OPERATOR	DATA	022H	; operator
NUM2L		DATA	023H	; low byte of second operand
NUM2H		DATA	024H	; high byte of second operand
EWB     DATA  0F8H  ;EWB TRACE SFR

; Program Start

reset:
        ; move stack pointer past register banks and variables
        MOV SP, #28H

	MOV P0, #00H
	MOV P2, #00H

	JMP getnum1

; Initialize values in memory	
initVar:
	MOV NUM1L, #00H
	MOV NUM1H, #00H
	MOV OPERATOR, #0FH
	MOV NUM2L, #00H
	MOV NUM2H, #00H
	MOV R5, #00H
	MOV R6, #00H
	RET

; Getting first operand
getnum1:
	MOV A, R1
	MOV A, R5
	MOV NUM1L, A
	MOV A, R6
	MOV NUM1H, A
	
	CALL keyscan
	call displaynum

	JMP getnum1	; continue getting first num

; Returns key pressed in (row,col) format in R7
; For example: R7 = #028H if 1 was pressed on the keypad
;            Keypad 
; Row # -----------------
; 8     | 7   8   9   + |
; 4     | 4   5   6   - |
; 2     | 1   2   3   * |
; 1     | C   0   =   / |
;       -----------------
; Col #   8   4   2   1
keyscan:
	PUSH ACC
	MOV A, R0
	PUSH ACC
	MOV A, R1
	PUSH ACC
	MOV A, R3
	PUSH ACC

        MOV P1, #00FH

waitkeyuploop:
	MOV A, P1
	ANL A, #00FH
	XRL A, #00FH
	JNZ waitkeyuploop

        MOV P1, #00FH

anykeyloop:
        MOV A, P1
        ANL A, #00FH
        XRL A, #00FH
        JZ anykeyloop
        MOV R0, A
        XRL A, #00FH
        MOV R3, A

        call lineclear
        MOV P1, #0EFH
        MOV R1, #010H
        NOP
        MOV A, P1
        ANL A, #00FH
        XRL A, R3
	MOV R2,#000H
        JZ scanmatch

        call lineclear
        MOV P1, #0DFH
        MOV R1, #020H
        NOP
        MOV A, P1
        ANL A, #00FH
        XRL A, R3
	MOV R2, #001H
        JZ scanmatch

        call lineclear
        MOV P1, #0BFH
        MOV R1, #040H
        NOP
        MOV A, P1
        ANL A, #00FH
        XRL A, R3
	MOV R2, #002H
        JZ scanmatch

        call lineclear
        MOV P1, #07FH
        MOV R1, #080H
        NOP
        MOV A, P1
        ANL A, #00FH
        XRL A, R3
	MOV R2, #003H
        JZ scanmatch

        MOV P1, #00FH
        JMP keyscan
scanmatch:
        MOV A, R1
        ORL A, R0  	; combine into scancode

	MOV R7, A	; R7 contains value in (row,col) format
	
keyscanend:
	POP ACC
	MOV R3, A
	POP ACC
	MOV R1, A
	POP ACC
	MOV R0, A
	POP ACC
	RET

; Input:
; R7 contains last key pressed
; R2 contains last key pressed in converted number
; R5 and R6 contains current number in hex
; Output:
; R5 and R6 contains new number in hex 
displaynum:
	MOV A, R7

	MOV R4, A
	MOV A, R2
	MOV B, #04H
	MUL AB
	MOV R2, A
	MOV A, R4
	ANL A, #00FH
	MOV R4, #000H
getnumloop:
	INC R4
	RR A
	ANL A, #00FH
	JNZ getnumloop
	DEC R4
	MOV A, R2
	ADD A, R4
	MOV R1, A

checknum2:
	CJNE A, #02H,checknum5
	MOV A, #00H
	JMP numfound 
checknum5:
	CJNE A, #05H,checknum6
	MOV A, #03H
	JMP numfound 
checknum6:
	CJNE A, #06H,checknum7
	MOV A, #02H
	JMP numfound 
checknum7:
	CJNE A, #07H,checknum9
	MOV A, #01H
	JMP numfound 
checknum9:
	CJNE A, #09H,checknum10
	MOV A, #06H
	JMP numfound 
checknum10:
	CJNE A, #0AH,checknum11
	MOV A, #05H
	JMP numfound 
checknum11:
	CJNE A, #0BH,checknum13
	MOV A, #04H
	JMP numfound 
checknum13:
	CJNE A, #0DH,checknum14
	MOV A, #09H
	JMP numfound 
checknum14:
	CJNE A, #0EH,checknum15
	MOV A, #08H
	JMP numfound 
checknum15:
	CJNE A, #0FH, checkclear 
	MOV A, #07H
	JMP numfound 
checkclear:
	CJNE A, #03H, checkplus
	JMP cleardisplay

checkplus:
	CJNE A, #0CH, checkminus
	JMP operatorfound 
checkminus:
	CJNE A, #08H, checkmultiply
	JMP operatorfound 
checkmultiply:
	CJNE A, #04H, checkdivide
	JMP operatorfound 
checkdivide:
	CJNE A, #00H, checkequalop
	JMP operatorfound 
checkequalop:
	CJNE A, #01H, numnotfound
	JMP equalfound 

equalfound:
	MOV R1, #02H
	MOV R7, A
	JMP displaynumend 

operatorfound:
	MOV R1, #00H
	MOV R7, A
	JMP displaynumend

numnotfound:
	MOV R7, #0FFH
	JMP displaynumend

numfound:
	MOV R1, #01H
	MOV R7, A
	
	; Shift number to the left before displaying
	call shiftnumleft

	; display decimal numbers	
	MOV A, R5	
	MOV P2, A

	MOV A, R6
	MOV P0, A
	call delay


displaynumend:
	RET

; R7 contains the new value
; R5 and R6 contains low and high byte of number to be shifted
shiftnumleft:
	PUSH ACC
shiftnumleftstart:
	MOV A, R7
	PUSH ACC
	
	MOV A, R6
	MOV R7, #004H
checkhighnumloop:
	RLC A
	JC noshift 
	DJNZ R7, checkhighnumloop
	JMP doshift

noshift:
	POP ACC
	MOV R7, A
	JMP shiftnumleftend

doshift:
	POP ACC
	SWAP A
	MOV R7, #004H

shiftbitleft:
	RLC A
	PUSH ACC
	; Take carry bit and rotate it into R5
	MOV A, R5
	RLC A
	MOV R5, A
	MOV A, R6
	RLC A
	MOV R6, A
	POP ACC
	DJNZ R7, shiftbitleft
		
shiftnumleftend:
	POP ACC
	RET

cleardisplay:
	MOV R5, #00H
	MOV A, R5
	MOV P2, A
	MOV R6, #00H
	MOV A, R6
	MOV P0, A
	CALL delay

	MOV R1, #03H
	JMP displaynumend
	
; Wait for no key press
lineclear:
        MOV P1, #0FFH
lineclearloop:
        MOV A, P1
        XRL A, #0FFH
        JNZ lineclearloop
        RET

delay:
        JB EWB.0,delayend  ; Jump if using EWB Trace Mode

        PUSH ACC
        MOV A, R5
        PUSH ACC
        MOV A, R6
        PUSH ACC
        MOV R5, #50  ; number of innerdelay's to call
        CLR A

outerdelay:
        MOV R6, A
        CALL innerdelay
        DJNZ R5, outerdelay

        POP ACC
        MOV R6, A
        POP ACC
        MOV R5, A
        POP ACC
delayend:
        RET
innerdelay:
        NOP
        NOP
        NOP
        NOP
        NOP
        DJNZ R6, innerdelay
        RET
END