/*****************************************************
     007.ASM

     接線：P0口接數碼管
           P2接矩陣鍵盤
     用定時中斷，若一段時間無操作，數碼管進入自到循環顯示  
      2010.09.05  
   *******************************************************/
   ORG 0000H
     LJMP MAIN
   ORG 000BH
     LJMP INT_T0
   ORG 0020H
 MAIN:       ;主程序
     MOV SP,#50H 
  MOV DPTR,#LED_DATA   ;取表首地址
  MOV TMOD,#01H     ;設置定時器T0工作模式
  MOV TH0,#15H    ;寫計時初值
     MOV TL0,#9FH
  MOV P2,#0FFH    ;P2口賦初值
  MOV R4,#00H     ;賦定時計數初值
  SETB 00H      ;00H為鍵值改變標志位
  SETB TR0      ;啟動定時器T0
  MOV IE,#82H   ;開中斷
  LCALL SHOW    ;數碼管初始化
loop:      ;主循環
    LCALL KEY_READ   ;讀鍵盤
 JBC 00H,LOOP0   ;判斷是否有鍵被按下，有則轉去刷新輸出并清零定時計數
 CJNE R4,#0C8H,LOOP  ;沒有鍵被按下，則判斷定時時間是否達到，到，則進入數碼管循環輸出
 LCALL SHOW1    ;沒到，則回到主循環，重新掃描鍵盤
 SJMP LOOP
LOOP0:
    LCALL SHOW
    MOV R4,#00H
 SJMP LOOP     ;輸出刷新完畢，回到主循環，重新掃描鍵盤

/*鍵盤掃描程序*/
KEY_READ:
    CLR P2.6    ;P2.6輸出低
 JB P2.0,N0_0
 MOV R0,#01H
 LCALL DELAY
 JB P2.0,N0_0
 JNB P2.0,$
 MOV R5,#04H
 SETB 00H
 SETB P2.6
 LJMP NEAT
N0_0:
    JB P2.1,N0_1
 MOV R0,#01H
 LCALL DELAY
 JB P2.1,N0_1
 MOV R5,#03H
 JNB P2.1,$
 SETB 00H
 SETB P2.6
 LJMP NEAT
N0_1:
    JB P2.2,N0_2
 MOV R0,#01H
 LCALL DELAY
 JB P2.2,N0_2
 JNB P2.2,$
 MOV R5,#02H
 SETB 00H
 SETB P2.6
 LJMP NEAT
N0_2:
    JB P2.3,N1_0
 MOV R0,#01H
 LCALL DELAY
 JB P2.3,N1_0
 JNB P2.3,$
 MOV R5,#01H
 SETB 00H
 SETB P2.6
 LJMP NEAT
N1_0:
    SETB P2.6
 CLR P2.5
 JB P2.0,N1_1
 MOV R0,#01H
 LCALL DELAY
 JB P2.0,N1_1
 JNB P2.0,$
 MOV R5,#08H
 SETB 00H
 SETB P2.5
 LJMP NEAT 
N1_1:
 JB P2.1,N1_2
 MOV R0,#01H
 LCALL DELAY
 JB P2.1,N1_2
 JNB P2.1,$
 MOV R5,#07H
 SETB 00H
 SETB P2.5
 LJMP NEAT 
N1_2:
 JB P2.2,N1_3
 MOV R0,#01H
 LCALL DELAY
 JB P2.2,N1_3
 JNB P2.2,$
 MOV R5,#06H
 SETB 00H
 SETB P2.5
 LJMP NEAT 
N1_3:
 JB P2.3,N2_0
 MOV R0,#01H
 LCALL DELAY
 JB P2.3,N2_0
 JNB P2.3,$
 MOV R5,#05H
 SETB 00H
 SETB P2.5
 LJMP NEAT
N2_0:
    SETB P2.5
 CLR P2.4
 JB P2.0,N2_1
 MOV R0,#01H
 LCALL DELAY
 JB P2.0,N2_1
 JNB P2.0,$
 MOV R5,#0CH
 SETB 00H
 SETB P2.4
 LJMP NEAT 
N2_1:
 JB P2.1,N2_2
 MOV R0,#01H
 LCALL DELAY
 JB P2.1,N2_2
 JNB P2.1,$
 MOV R5,#0BH
 SETB 00H
 SETB P2.4
 LJMP NEAT 
N2_2:
 JB P2.2,N2_3
 MOV R0,#01H
 LCALL DELAY
 JB P2.2,N2_3
 JNB P2.2,$
 MOV R5,#0AH
 SETB 00H
 SETB P2.4
 LJMP NEAT 
N2_3:
 JB P2.3,NEAT
 MOV R0,#01H
 LCALL DELAY
 JB P2.3,NEAT
 JNB P2.3,$
 MOV R5,#09H
 SETB 00H
 SETB P2.4
 LJMP NEAT 
NEAT:
    SETB P2.4
    RET 
  

/*顯示子程序*/
SHOW:
    MOV A,R5
 MOVC A,@A+DPTR
 MOV P0,A
    RET

/*循環顯示子程序*/

SHOW1:      ; 
  MOV R3,#00H
LOOP1:
     MOV A,R3
  MOVC A,@A+DPTR
  MOV P0,A
  MOV R0,#35H
  LCALL DELAY
  INC R3
  LCALL KEY_READ
  JB 00H,RETUN1
  CJNE R3,#10H,LOOP1
  MOV R3,#00H
  SJMP LOOP1
RETUN1:
     RET

/*延時子程序*/

DELAY:
D0:  MOV R2,#0FH
D1:  MOV R1,#0BFH
D2:  DJNZ R1,D2
     DJNZ R2,D1
  DJNZ R0,D0
  RET    
     

/*定時中斷T0處理子程序*/


INT_T0:
     CLR EA
     PUSH ACC
  INC R4
  MOV TH0,#15H
     MOV TL0,#9FH
  POP ACC
  SETB EA
     RETI

/*數碼管顯示代碼，0~F*/

LED_DATA:
     DB 03H,9FH,25H,0DH,99H,49H,41H,1FH
  DB 01H,09H,11H,0C1H,63H,85H,61H,71H

  END