Measurement Computing GPIB-488 - Manual (Page 67)

Chapter 3 GPIB 488.1 Library Reference
Programming Reference Manual 3-54 GPIB-488
IBWRTA
Writes data asynchronously from a string to the specified device or GPIB interface board.
Syntax
C ibwrta (int boarddev, char buf[], unsigned long
bytecount)
Parameters
boarddev is an integer containing the board or device handle.
buf is the storage buffer for the data. Up to 4 gigabytes-1 (2 32 -1 bytes) can be stored. String
size may be limited by the language you are using. Check documentation for your language.
bytecount specifies the number of bytes to be written.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA .
iberr will contain an error code of the first error detected, if an error occurred. An EADR
results if boarddev specifies a board and the board has not already been addressed to talk.
ibcnt , ibcntl will contain the number of bytes that were written. ibcnt is a 16-bit integer.
ibcntl is a 32-bit integer. If the requested count was greater than 64 K, use ibcntl instead
of ibcnt .
Usage Notes
Asynchronous I/O is not explicitly supported and will be treated as synchronous.
Example
In this example, ibwrt sends a command (" UPLOAD ") to a device. The device expects a block
of data to be sent immediately. ibwrta begins a transfer of 5000 bytes in the background and
program continues on into the WHILE loop. The WHILE loop calls ibwait with MASK set
to 0 to update ibsta . The WHILE loop checks ibsta to see if ibwrta has completed or any
error have occurred. The program may do anything else within the WHILE loop except make
other GPIB I/O calls.
C char writebuffer[5000];
ibwrt (device, "UPLOAD")
ibwrta (device, writebuffer, 5000);
while ( (ibsta & CMPL+ERR) == 0)
ibwait (device, 0)