Measurement-computing GPIB-488 Manual do Utilizador descarregar pdf (Página 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

-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

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)

1 2 ... 62 63 64 65 66 67 68 69 70 71 72 ... 115 116

Sem comentários

Measurement-computing GPIB-488 Manual do Utilizador Página 67