DECLARE FUNCTION AskForBaseAddress! (OldOne AS INTEGER)



'*--------------------------------------------------------------------
'* Sample program demonstrating register level access
'* of input data
'*--------------------------------------------------------------------

'
'Declare table of offsets into data registers
'
DIM OFS%(6)
OFS%(0) = 0
OFS%(1) = 1
OFS%(2) = 2
OFS%(3) = 4
OFS%(4) = 5
OFS%(5) = 6

'
' Display program header information
'
CLS
PRINT "                  SAMPLE 1.BAS"
PRINT
PRINT "Demonstration program  for accessing input data."
PRINT "Program reads each of the input ports"; " 16 input"
PRINT "channels and displays on/off status of those channels."
PRINT : PRINT
Address% = AskForBaseAddress!(&H350)

CLS
PRINT : PRINT : PRINT
PRINT "Board Configuration:"
PRINT
PRINT " -- Base Address is "; HEX$(Address%); " hex"
PRINT " -- If you are using the option C card, all mode switches"
PRINT "    should be OFF."
PRINT " -- All remaining jumper settings are irrelevant"
PRINT : PRINT : PRINT
PRINT "Press any key to continue "
A$ = INPUT$(1)

'
' Main program loop
'
CLS
LOCATE 4, 1
INPUT "Enter port nunmber to read (0,1,2): "; PORT%

READLOOP:
CLS
LOCATE 2, 28
PRINT "Reading Port ";
PRINT PORT%
LOCATE 4, 27
PRINT "Input       Status"
LOCATE 5, 27
PRINT "------------------"

'
' Read the first 8 input channels of the current port
'
BYTE% = INP(Address% + OFS%(2 * PORT%))
FOR i% = 0 TO 7
        LOCATE 6 + i%, 28
        PRINT USING "##"; i%
        BIT% = BYTE% MOD 2
        BYTE% = INT(BYTE% / 2)
        LOCATE 6 + i%, 43
        IF BIT% = 1 THEN
                PRINT "ON "
        ELSE
                PRINT "OFF"
        END IF
NEXT i%

'
' Read second 8 input channels of the current port
'
BYTE% = INP(Address% + OFS%(2 * PORT% + 1))
FOR i% = 8 TO 15
        LOCATE 6 + i%, 28
        PRINT USING "##"; i%
        BIT% = BYTE% MOD 2
        BYTE% = INT(BYTE% / 2)
        LOCATE 6 + i%, 43
        IF BIT% = 1 THEN
                PRINT "ON "
        ELSE
                PRINT "OFF"
        END IF
NEXT i%

LOCATE 24, 10
PRINT "Press 'Q' to quit; press any other key to re-read the port"
A$ = INPUT$(1)
IF A$ = "Q" THEN GOTO QUIT
IF A$ = "q" THEN GOTO QUIT
GOTO READLOOP

QUIT:
CLS
END

FUNCTION AskForBaseAddress (OldOne AS INTEGER)
   Msg$ = ""
   NewOne% = 0: Success = 0: Dummy% = 0
   AddrInputPosX = 0: AddrInputPosY = 0

   PRINT "Please enter the Base Address (0000-FFFF) for your card (in hex)"
   PRINT "or press ENTER for "; HEX$(OldOne%); "."
   PRINT ">";
   AddrInputPosX = POS(0): AddrInputPosY = CSRLIN
   WHILE Success = 0
     LOCATE AddrInputPosY, AddrInputPosX
     PRINT "                                                                               "
     LOCATE AddrInputPosY, AddrInputPosX
     LINE INPUT Msg$
     NewOne% = VAL("&H0" + LEFT$(Msg$, 4))
     Success = 1
     Dummy% = NewOne%
     IF (Msg$ = "") THEN
        LOCATE AddrInputPosY, AddrInputPosX
        PRINT HEX$(OldOne%)
        Success = 1
        Dummy% = OldOne%
     END IF
  WEND
  AskForBaseAddress = Dummy%
END FUNCTION