;FOR    EAT598
PI      EQU     0F208H          ;開(kāi)關(guān)輸入口地址
PO      EQU     0F200H          ;輸出口地址

        ORG     0000H
        SJMP    START
        ORG     0040H
START:
        MOV     SP,#60H
        CLR     C
        PUSH    PSW           
        mov     r5,#01110111B   ;R5與C一起組成狀態(tài)存儲(chǔ)器
READ:
        MOV     DPTR,#PI
        MOVX    A,@DPTR         ;讀開(kāi)關(guān)狀態(tài)
        JB      ACC.0,DIRECT0   ;判斷轉(zhuǎn)動(dòng)方向
        JB      ACC.1,DIRECT1   ;
        SJMP    READ            ;正反向開(kāi)關(guān)均未開(kāi)則重讀開(kāi)關(guān)
DIRECT0: 
        MOV     R7,#00H         ;設(shè)置方向標(biāo)志
        SJMP    SPEED
DIRECT1:
        MOV     R7,#0FFH        ;設(shè)置方向標(biāo)志
SPEED:
        JB      ACC.2,SPEED0    ;判定轉(zhuǎn)速開(kāi)關(guān)
        JB      ACC.3,SPEED1
        JB      ACC.4,SPEED2
        JB      ACC.5,SPEED3
        JB      ACC.6,SPEED4
        JB      ACC.7,SPEED5
        AJMP    READ            ;無(wú)任何速度開(kāi),則重讀開(kāi)關(guān)
SPEED0: MOV     R6,#61H         ;設(shè)置轉(zhuǎn)速0常數(shù)
        AJMP    WAVE
SPEED1: MOV     R6,#51H         ;設(shè)置轉(zhuǎn)速1常數(shù)
        AJMP    WAVE
SPEED2: MOV     R6,#31H         ;設(shè)置轉(zhuǎn)速2常數(shù)
        AJMP    WAVE
SPEED3: MOV     R6,#21H         ;設(shè)置轉(zhuǎn)速3常數(shù)
        AJMP    WAVE
SPEED4: MOV     R6,#11H         ;設(shè)置轉(zhuǎn)速4常數(shù)
        AJMP    WAVE
SPEED5: MOV     R6,#09H         ;設(shè)置轉(zhuǎn)速5常數(shù)
        MOV     B,R6
WAVE:
        LCALL   DELAY           ;延時(shí),決定轉(zhuǎn)速
        DJNZ    R6,WAVE
        MOV     DPTR,#PO        ;置輸出口地址
        MOV     A,R5
        CJNE    R7,#00H,NEG     ;判斷轉(zhuǎn)向標(biāo)志
        POP     PSW
        RL      A               ;改變相位
        SJMP    SSS
NEG:    POP     PSW
        RR      A               ;改變相位
SSS:
        PUSH    PSW
        MOV     R5,A            ;保存相位
        ANL     A,#0FH
        MOVX    @DPTR,A         ;相位輸出
        AJMP    READ
DELAY:                          ;延時(shí)子程序
        MOV     R0,#20H
delay1: mov     r1,#04fh
        djnz    r1,$
        DJNZ    R0,delay1
        RET
        END