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Din.vi – Measurement Computing UL for NI LabVIEW User Manual

Page 75

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Universal Library Virtual Instruments (VIs)

Digital I/O VIs

DIn.VI

Reads a digital input port.

Inputs:

BoardNum

[U32] - The board number assigned when installed with InstaCal. Can

be 0 to 100.

PortNum

[I32] - Specifies which digital I/O port to read.

Outputs:

DataValue

[I16] - Digital input value.

ErrCode

[I32] - Error code. See ErrMsg.VI

Arguments:

BoardNum

The board number associated with a board when it was installed with InstaCal.

PortNum

If the port type is not

AUXPORT

, the specified port must be configured for input.

For many boards, AUXPORT is not configurable. However, some later boards do

require that the AUXPORT be configured using DCfgPort.VI or DCfgBit.VI.
Please see board details for more information.

The table below shows which ports are in which 82C55 and 8536 digital chips. The

CIO-DIO192 supports eight 82C55 chips—the most available on a single board.
The PCI-INT32 support two 8536 chips— the most available on a single board.

Mnemonic

Bit #

8255 Chip #

Chip Address

8536 Chip #

Chip Address

FIRSTPORTA

0 - 7

1A

Base + 0

1A

Base + 0

FIRSTPORTB

8 - 15

1B

1B

FIRSTPORTCL

16 - 19

1CL

1C

FIRSTPORTCH

20 - 23

1CH

Not present

SECONDPORTA

24 - 31

2A

Base + 4

2A

Base + 4

SECONDPORTB

32 - 39

2B

2B

SECONDPORTCL

40 - 43

2CL

2C

SECONDPORTCH

44 - 47

2CH

No port C High in 8536 chips

and so on, to the last chip on the board as: THIRDPORTx, FOURTHPORTx, FIFTHPORTx, SIXTHPORTx,
SEVENTHPORTx and...

EIGHTHPORTA

168 - 175

8A

Base + 28

EIGHTHPORTB

176 - 183

8B

EIGHTHPORTCL

184 - 187

8CL

EIGHTHPORTCH

188 - 191

8CH

DataValue

Digital input value. The size of the ports vary. If it is an eight-bit port, then the

returned value will be in the range 0- 255. If it is a four bit port the value will be in
the range 0

-15.

ErrCode

Error code returned from the Universal Library. Zero if no error occurred. Use the

ErrMsg VI to convert

ErrCode

into a readable string.

Important - Read board-specific information in UL User's Guide

Refer to the example programs and the board-specific information contained in the Universal Library User's
Guide (available on our web site at

www.mccdaq.com/PDFmanuals/sm-ul-user-guide.pdf

) for clarification of

valid

PortNum

values.

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