t15.asm

一些单片机的51实例

NAME T15                       ;0809实验
PORT    EQU  0CFA0H
CSEG AT 0000H
        LJMP START
CSEG AT 4100H
START:  MOV DPTR,#PORT         ;启动通道0
        MOVX @DPTR,A
        MOV R0,#0FFH
LOOP1:  DJNZ R0,LOOP1          ;等待中断
        MOVX A,@DPTR
        MOV R1,A       
DISP:   MOV  A,R1              ;从R1中取转换结果
        SWAP A                 ;分离高四位和低四位
        ANL  A,#0FH            ;并依次存放在50H到51H中
        MOV  50H,A
        MOV  A,R1
        ANL  A,#0FH
        MOV  51H,A        
LOOP:   MOV  DPTR,#0CFE9H     ;写显示RAM命令字
        MOV  A,#90H
        MOVX @DPTR,A
        MOV  R0,#50H          ;存放转换结果地址初值送R0
        MOV  R1,#02H
        MOV  DPTR,#0CFE8H     ;8279数据口地址
DL0:    MOV  A,@R0
        ACALL TABLE           ;转换为显码
        MOVX @DPTR,A          ;送显码输出
        INC  R0
        DJNZ R1,DL0
        SJMP DEL1
TABLE:  INC  A
        MOVC A,@A+PC
        RET
DB      3FH,06H,5BH,4FH,66H,6DH,7DH,07H
DB      7FH,6FH,77H,7CH,39H,5EH,79H,71H
DEL1:   MOV  R6,#255          ;延时一段时间使显示更稳定
DEL2:   MOV  R5,#255
DEL3:   DJNZ R5,DEL3
        DJNZ R6,DEL2
        LJMP START            ;循环
        END