# cbInByte()

Reads a byte from a hardware register on a board.

## Function Prototype

C/C++

int cbInByte(int BoardNum, int PortNum)

Visual Basic

Function cbInByte(ByVal BoardNum&, ByVal PortNum&) As Long

## Arguments

BoardNum

The number associated with the board when it was installed with InstaCal or created with cbCreateDaqDevice(). BoardNum may be 0 to 99.

PortNum

Register within the board. Boards are set to a particular base address. The registers on the boards are at addresses that are offsets from the base address of the board (BaseAdr + 0, BaseAdr + 2, etc).

Set this argument to the offset for the desired register. This function takes care of adding the base address to the offset, so that the board's address can be changed without changing the code.

## Returns

- The current value of the specified register.

## Notes

- cbInByte() is used to read 8 bit ports. cbInWord() is used to read 16-bit ports.
- This function was designed for use with ISA bus boards. Use with PCI bus boards is not recommended.