PIC keyboard scan assembler
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Keyboard scanning subroutine -- key 16, low four digit output and high four digit input of port D JIANPAN MOVLW 00H MOVWF PORTD MOVLW 0F0H ANDWF PORTD,W SUBLW 0F0H BTFSC STATUS,Z; Judge whether the top four digits of port D are all "1" RETURN ; Yes, keyless input, return CALL DELAY10MS; No, there is a key input, with a delay of 20ms CALL DELAY10MS CALL DELAY10MS MOVLW 00H ; Judge again MOVWF PORTD MOVLW 0F0H ANDWF PORTD,W SUBLW 0F0H BTFSC STATUS,Z; Judge whether the top four digits of port D are all "1" RETURN ; False input, return MOVLW 0FEH ; Confirm that there is key input and judge line by line. First, rd0 = 0 MOVWF PORTD BTFSS PORTD,4 ; Key "0" GOTO JIAN0 BTFSS PORTD,5 ; Key "1" GOTO JIAN1 BTFSS PORTD,6 ; Key "2" GOTO JIAN2 BTFSS PORTD,7 ; Key "3" GOTO JIAN3 MOVLW 0FDH ; Confirm that there is key input and judge line by line. First, RD1 = 0 MOVWF PORTD BTFSS PORTD,4 ; Key "4" GOTO JIAN4 BTFSS PORTD,5 ; Key "5" GOTO JIAN5 BTFSS PORTD,6 ; Key "6" GOTO JIAN6 BTFSS PORTD,7 ; Key "7" GOTO JIAN7 MOVLW 0FBH ; Confirm that there is key input and judge line by line. First, rd0 = 2 MOVWF PORTD BTFSS PORTD,4 ; Key "8" GOTO JIAN8 BTFSS PORTD,5 ; Key "9" GOTO JIAN9 BTFSS PORTD,6 ; Key "a" GOTO JIANA BTFSS PORTD,7 ; Key "B" GOTO JIANB MOVLW 0F7H ; Confirm that there is key input and judge line by line. First, rd0 = 3 MOVWF PORTD BTFSS PORTD,4 ; Key "C" GOTO JIANC BTFSS PORTD,5 ; Key "d" GOTO JIAND BTFSS PORTD,6 ; Key "e" GOTO JIANE BTFSS PORTD,7 ; Key "F" GOTO JIANF RETURN;.................; 10 ms delay subroutine DELAY10MS MOVLW 0FH MOVFW 20HLP2 MOVLW 0FFH MOVWF 21HLP1 DECFSZ 21H,F GOTO LP1 DECFSZ 22H,F GOTO LP2 RETURN;........................; Key '0' subroutine, customizable JIAN0 CALL SFANG; Call keyboard release subroutine . . . RETURN;...................; Keyboard release waiting subroutine SFANG MOVLW 00H MOVWF PORTD MOVLW 0F0H ANDWF PORTD,W SUBLW 0F0H BTFSS STATUS,Z GOTO SFANG; Key not released CALL DELAY10MS; Released, delayed CALL DELAY10MS CALL DELAY10MS MOVLW 0F0H; Judge again ANDWF PORTD,W SUBLW 0F0H BTFSS STATUS,Z GOTO SFANG; It was a false release just now, waiting for further judgment RETURN
The above are all program codes
Another assembly language source code:
My keyboard scanner:
key equ p2disp equ p0
; 7------+--+--+--+; 6------+--+--+--+; 5------+--+--+--+; 4------+--+--+--+; 3______| | | |; 2_________| | |; 1____________| |; 0_______________|
org 0000h ajmp start org 0100hstart: mov disp,#0 mov dptr,#tabloopscan:acall keyin acall keyoff mov a,r0 movc a,@a+dptr mov disp,a ajmp loopscan
keyin: mov key,#0fh mov a,key cjne a,#0fh,select sjmp keyinselect: mov a,key cjne a,#0eh,next1 ajmp row1next1: cjne a,#0dh,next2 ajmp row2next2: cjne a,#0bh,next3 ajmp row3next3: ajmp row4
row1: mov key,#0feh mov a,key cjne a,#0feh,row1scan ajmp row2row1scan:cjne a,#0eeh,row11 mov r0,#12 acall delay20ms ajmp scanendrow11: cjne a,#0deh,row12 mov r0,#13 acall delay20ms ajmp scanend row12: cjne a,#0beh,row13 mov r0,#14 acall delay20ms ajmp scanendrow13: mov r0,#15 acall delay20ms ajmp scanend
row2: mov key,#0fdh mov a,key cjne a,#0fdh,row2scan ajmp row3row2scan:cjne a,#0edh,row21 acall delay20ms mov r0,#8 ajmp scanendrow21: cjne a,#0ddh,row22 mov r0,#9 acall delay20ms ajmp scanend row22: cjne a,#0bdh,row23 mov r0,#10 acall delay20ms ajmp scanendrow23: mov r0,#11 acall delay20ms ajmp scanend
row3: mov key,#0fbh mov a,key cjne a,#0fbh,row3scan ajmp row4row3scan:cjne a,#0ebh,row31 mov r0,#4 acall delay20ms ajmp scanendrow31: cjne a,#0dbh,row32 mov r0,#5 acall delay20ms ajmp scanend row32: cjne a,#0bbh,row33 mov r0,#6 acall delay20ms ajmp scanendrow33: mov r0,#7 acall delay20ms ajmp scanend
row4: mov key,#0f7h mov a,key cjne a,#0e7h,row41 mov r0,#0 acall delay20ms ajmp scanendrow41: cjne a,#0d7h,row42 mov r0,#1 acall delay20ms ajmp scanend row42: cjne a,#0b7h,row43 mov r0,#2 acall delay20ms ajmp scanendrow43: mov r0,#3 acall delay20ms ajmp scanend
scanend:ret
; Judge whether to release keyoff: mov key,#0fh mov a,key cjne a,#0fh,keyret sjmp keyoffkeyret: acall delay20ms ret;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!; 12Mhz Crystal!!!!!!!!!!!!!!!!!!!!!!! 12 cycle MCU delay20ms: mov R7, #250delay20msd0: mov R6, #60delay20msd1: djnz R6$ djnz r7,delay20msd0 ret tab:db 11100111b,10000100b,11010011b,11010110b,10110100b,
01110110b,01110111b,11000100b,11110111b,11110110b
db 11110101b,00110111b,01100011b,10010111b,01110011b,
01110001b,01100111b,10110101b,00100001b,10000111bdb 00100011b,00010101b,00010111b,11110001b,11110100b,10110110b
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