rjexp12.asm

显示屏相关程序实现显示屏点亮控制等功能.

DATA  SEGMENT
MESS  DB  '按任意键退出',0DH,0AH,'$'
TABLE DW   524,588,660,698,784,880,988,1048,1176,1320,0
TABLE1 DB  31H,31H,32H,31H,34H,33H,3BH
       DB  31H,31H,32H,31H,35H,34H,3BH
       DB  31H,31H,38H,36H,34H,33H,32H,3BH
       DB  36H,36H,36H,34H,35H,34H,3BH,0AAH
DATA ENDS
STACK SEGMENT
STA  DB  256 DUP(?)
TOP  EQU LENGTH STA
STACK  ENDS
CODE SEGMENT
ASSUME CS:CODE,DS:DATA,SS:STACK,ES:DATA
START:MOV  AX,DATA
      MOV  DS,AX
      MOV  AX,STACK
      MOV  SS,AX
      MOV  AX,TOP
      MOV  SP,AX
      MOV  AH,09H
      LEA  DX,MESS
      INT  21H
KK:   LEA  SI,TABLE1
SING: MOV  AH,06H
      MOV  DL,0FFH
      INT  21H      ;接收键入字符
      JNZ  FINISH   ;有键按下则退出程序
      MOV  AL,[SI]
      CMP  AL,3BH
      JNE   DDD
      CALL  DELAY
      JMP  QQ
DDD: CMP  AL,0AAH
      JE   KK
      SUB  AL,31H
      SHL  AL,01    ;转化为相表偏移量(表中每项占两字节)
      MOV  BL,AL
      MOV  AX,0000H
      MOV  DX,12H   ;常数120000H作为被除数
      MOV  BH,00
      DIV  WORD PTR [TABLE+BX]
      MOV  BX,AX    ;求得频率值→BX
      MOV  AL,10110110B
      OUT  43H,AL   ;设置计数器2计数初值低位
      MOV  AX,BX
      OUT  42H,AL   ;设置计数器2计数初值低位
      MOV  AL,AH
      OUT  42H,AL   ;设置计数初值高位
      IN   AL,61H
      OR   AL,03H
      OUT  61H,AL    ;打开与门
      CALL DELAY
      IN AL,61H
      AND AL,0FCH
      OUT  61H,AL    ;关闭
QQ:   INC  SI
      JMP  SING      ;循环
FINISH:MOV  AX,4C00H
      INT  21H       ;结束
DELAY PROC  NEAR        ; 延时子程序
      PUSH  CX
      PUSH  AX
      MOV   AX,06H
 X1:  MOV  CX,0FFFFH
 X2:  DEC   CX     
      JNZ   X2
      DEC   AX
      JNZ   X1
      POP   AX
      POP   CX
      RET
DELAY ENDP
CODE 	ENDS
		END START