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Appendix B
FCS Check Program
Examples (BASIC)
Calculation Examples for Sending FCS
DATA$
Sample Data Line
L
Data Length
CODE$
Data Character
A
Exclusive Operation
100 ’*****CALCULATE FCS*****
110 ’*FCSSET
120 L=LEN(DATA$)
130 A=0
140 FOR J=1 TO L
150 CODE$=MID$(DATA$,J,1)
160 A=ASC(CODE$)XOR A
170 NEXT J
180 FCS$=HEX$(A)
190 IF LEN(FCS$)=1 THEN FCS$=”0”+FCS$
200 RETURN
FCS Check Sub Routine Examples for Received
Data
1000 ’*****FCSHECK*****
1010 ’*FCSHECK
1020 Q=0:FCSCK$=”OK”
1030 PRINT RESPONSE $
1040 LENGS=LEN(RESPONSE$)–3
1050 FCSP$=MID$(RESPONSE$,LENGS+1,2) ......Response Data of FCS
1060 FOR J=1 TO LENGS .....................Calculation Range of FCS
1070 Q=ASC(MID$(RESPONSE$,J,1))XOR Q
1080 NEXT J
1090 FCSD$=HEX$(Q)
1100 IF LEN(FCSD$)=1 THEN FCSD$=”0”+FCSD$ .FCS calculated in a program
1110 IF FCSD$ < > FCSP$ THEN FCSCK$=”ERR”
1120 PRINT ”FCSD$=”;FCSD$;”FCSP$=”;FCSP$;
”FCSCK$=”;FCSCK$; .....FCS correctly received :OK
1130 RETURN FCS not received correctly:ERR
