paritycheck.sdi

该应用软件可以实现大多数单片机的仿真实验

,,,;Simple Parity Checker
,,,
,,,        LIST    p=10F202 ;
,,,        #include "P10F202.INC" ; Include header file
,,,
,,,        CBLOCK 0x08   ; Temporary storage
,,,        dc1
,,,        bitcount
,,,        databyte
,,,        onecount
,,,        ENDC
,,,
,,,
,,,        ; Vector for normal start up.
,,,        org     0
00000000,0A01,,        goto    start
,,,
,,,
,,,; Main program starts here:
00000001,0040,start,start   clrw                    ; Clear W.
00000002,0026,,        movwf   GPIO            ; Ensure PORT is zero before we enable it.
00000003,0CFD,,        movlw   0xFD            ; All inputs except GP1
00000004,0006,,        tris    GPIO
,,,
,,,;Wait for a start bit
00000005,0606,wstart,wstart  btfsc   GPIO,0
00000006,0A05,,        goto    wstart
,,,
00000007,0924,,        call    waithalf
,,,
,,,;Check start bit still low
00000008,0606,,        btfsc   GPIO,0
00000009,0A05,,        goto    wstart
,,,
,,,;Loop 8 times to capture data byte
0000000A,006A,,        clrf    databyte
0000000B,006B,,        clrf    onecount
0000000C,0C08,,        movlw   8
0000000D,0029,,        movwf   bitcount
0000000E,0921,l1,l1      call    waitfull
0000000F,0306,,        rrf     GPIO,W
00000010,032A,,        rrf     databyte,F
00000011,0606,,        btfsc   GPIO,0
00000012,02AB,,        incf    onecount,F
00000013,02E9,,        decfsz  bitcount,F
00000014,0A0E,,        goto    l1
,,,
,,,;Wait for parity bit
00000015,0921,,        call waitfull
,,,
,,,;Add the parity bit to the 1's count
00000016,0606,,        btfsc   GPIO,0
00000017,02AB,,        incf    onecount,F
,,,;Add the state from GP2 to the 1's count so as to switch between
,,,;checking even or odd parity
00000018,0646,,        btfsc   GPIO,2
00000019,02AB,,        incf    onecount,F
,,,;If the 1's count is odd we are OK, if it's odd we had a parity error
0000001A,0040,,        clrw
0000001B,070B,,        btfss   onecount,0
0000001C,0C02,,        movlw   0x02
,,,;Write result to the LED
0000001D,0026,,        movwf   GPIO
,,,
,,,;Wait for stop bit, then go again
0000001E,0706,wstop,wstop   btfss   GPIO,0
0000001F,0A1E,,        goto wstop
00000020,0A05,,        goto wstart
,,,
,,,
,,,;Wait a full bit time
,,,;
00000021,,waitfull,waitfull
00000021,0924,,        call waithalf
00000022,0924,,        call waithalf
00000023,0800,,        return
,,,
,,,;Wait half a bit time
,,,;
00000024,,waithalf,waithalf
00000024,0C89,,        movlw 0x89
00000025,0028,,        movwf dc1
00000026,,wh1,wh1
00000026,02E8,,        decfsz  dc1,f
00000027,0A26,,        goto wh1
00000028,0800,,        return
,,,
,,,        END