HD7279A键盘检测汇编程序 -

标题: HD7279A键盘检测汇编程序 [打印本页]

作者: heicad 时间: 2014-6-10 04:30
标题: HD7279A键盘检测汇编程序
ORG  0000H
lJMP  START                ；检测到按键并显示
ORG  0100H
BIT_COUNT DATA 07FH
TIMER    DATA 07EH
TIMER1    DATA 07DH
TEN    DATA 07CH
DATA_IN    DATA 020H
DATA_OUT DATA 021H
DAT BIT P1.2    ;HD7279A DATA P1.2
KEY BIT P1.3 ;HD7279A KEY P1.3
CS  BIT P1.0 ;HD7279A CS P1.4
CLK BIT P1.1    ;HD7279A CLK P1.5
START: MOV  SP,#2FH ;
      MOV TIMER,#50  ; 25MS
START_DELAY: MOV  TIMER1,#255
START_DELAY1:DJNZ TIMER1,START_DELAY1
  DJNZ TIMER,START_DELAY
  MOV  P1,#70H
MOV 29H,#0A4H ; ( )复位
CALL SEND
SETB CS ; CS
MAIN: mov  c,p1.4
   JC    MAIN ;
MOV 29H,#15H ;
  CALL SEND
  CALL RECEIVE
DISP:MOV 29H,#0C8H
      ACALL SEND
   MOV 29H,28H
   ACALL SEND
   SJMP DISP
SEND:CLR P1.7
   MOV R3,#08H
   ACALL LONG
SEND_LOOP:MOV C,29H.7
      MOV P1.6,C
      SETB P1.5
      ACALL SHORT
      CLR P1.5
      ACALL SHORT
      MOV A,29H
      RL A
      MOV 29H,A
      DJNZ R3,SEND_LOOP
      CLR P1.6
      RET
;*******************************************
;  HD7279
;*******************************************
RECEIVE: MOV BIT_COUNT,#8 ; =8
SETB DAT ; P1.2(DATA)

  CALL LONG  ;
RECEIVE_LOOP:  SETB CLK ; CLK
CALL SHORT  ;
MOV A,28H  ;
  RL A
  MOV 28H,A
MOV C,DAT ;
  MOV 28H.0,C
CLR CLK ; CLK
  CALL SHORT
  DJNZ BIT_COUNT,RECEIVE_LOOP; 8
CLR DAT  ; DAT ( )
  RET
;*******************************************
;*******************************************
LONG: MOV  TIMER,#25 ; 50uS
DELAY_LOOP: DJNZ  TIMER,DELAY_LOOP
RET
SHORT: MOV  TIMER,#4 ; 8uS
SHORT_LP: DJNZ TIMER,SHORT_LP
RET
END

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