- GPIB-PC User Manual for the IBM Personal Computer and Compatibles April 1988 Edition Part Number 320014-01

BASICA/QuickBASIC GPIB-PC Function Calls Section Four A
GPIB-PC User Manual 4A-6 ©National Instruments Corp.
perform arithmetic operations on the data and want to avoid the
overhead of converting the character bytes of IBRD and IBWRT into
integer format and back again.
IBRDI and IBWRTI are passed data in the form of an integer array,
instead of a character string whose maximum length is limited to 255
bytes. Using these functions, you may store more than 255 bytes in a
single buffer and do not have to convert each pair of data bytes to an
integer before doing arithmetic operations on the data. Internally, the
IBWRTI function sends each integer to the GPIB in low-byte, high-byte
order. The IBRDI function reads a series of data bytes from the GPIB
and stores them into the integer array in low-byte, high-byte order.
In addition to IBRDI and IBWRTI, the asynchronous functions IBRDIA
and IBWRTIA are provided to perform asynchronous integer reads and
writes.
The functions are listed alphabetically by function name in this section.
Table 4A.1 provides a summary of the BASICA GPIB-PC functions and
Table 4A.2 provides a summary of the QuickBASIC GPIB-PC functions.
BASICA/QuickBASIC "ON SRQ" Capability
BASICA programs may be interrupted on the occurrence of the GPIB
SRQ signal. When the interrupt occurs, a branch can be taken to a
service routine which determines the cause of the SRQ and takes the
appropriate action.
National Instruments uses this statement to intercept SRQ interrupt and
make them available to user programs. For more complete information
regarding the operation of "ON PEN", refer to the IBM BASICA User's
Manual and Microsoft QuickBASIC under the "ON PEN Statement."
All the information in that section applies to both the light pen and to
the GPIB SRQ signal.
Statements such as "ON PEN" which intercept interrupts are a special
feature of some versions of BASIC, including BASICA and
QuickBASIC. These statements, however, are not usually a feature of
non-BASIC languages and are not necessarily supported in other
National Instruments language interfaces. To determine if this feature is
supported in languages other than BASICA and QuickBASIC, refer to
the manual supplement that comes with that language.