Section Four A
BASICA/QuickBASIC GPIB-PC Function Calls
©National Instruments Corp.
4A-47
GPIB-PC User Manual
BASICA/QuickBASIC
BASICA/QuickBASIC
IBRD
IBRD
Purpose:
Read data to string
Format:
CALL IBRD (BD%,RD$)
Remarks:
BD%
specifies a device or an interface board.
RD$
identifies the storage buffer for data bytes that are read
from the GPIB.
The
IBRD
function reads from 1 to 255 bytes of data from a
GPIB device. In QuickBASIC the
IBRD
function reads
from 1 to 32K bytes of data from a GPIB device.
Device
IBRD
Function:
When
BD%
specifies a device, the following board steps are performed
automatically to read from the device:
1.
The
IBCMD
function is called to address the device to talk and
the access board to listen.
2.
The board
IBRD
function is called to read the data from the
device, as explained in the following discussion.
3.
The
IBCMD
function is called to unaddress the access board
and unaddress all devices using the Untalk and Unlisten
commands.
Other command bytes may be sent as necessary.
When the device
IBRD
function returns,
IBSTA%
holds the latest
device status;
IBCNT%
is the actual number of data bytes read from the
device; and
IBERR%
is the first error detected if the ERR bit in
IBSTA%
is set.
Board
IBRD
Function:
When
BD%
specifies an interface board, the
IBRD
function attempts to
read from a GPIB device that is assumed to already be properly
initialized and addressed.
If the access board is CIC, the
IBCMD
function must be called prior to
IBRD
to address a device to talk and the board to listen. Otherwise, the
device on the GPIB that is the CIC must perform the addressing.