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Chapter 3      Software Overview

NI-VXI User Manual

3-18

© National Instruments Corporation

DefaultWSSLcmdHandler

 calls 

GenProtError

 with a protocol error

code of 

UnSupCom

 for every Longword Serial command received.

DefaultWSSrdHandler

 is the default handler for the 

WSSrd

 interrupt,

which 

InitVXIlibrary

 automatically installs when it initializes the

NI-VXI software. When 

WSSrd

 reaches the specified count or an END

bit, or an error occurs, it calls the 

WSSrd

 interrupt handler with the

status of the call. The default handler sets the global variables

WSSrdDone

, 

WSSrdDoneStatus

, and 

WSSrdDoneCount

. You can

use the variable 

WSSrdDone

 to poll until the operation is complete.

Afterwards, you can inspect 

WSSrdDoneStatus

 and

WSSrdDoneCount

 to see the outcome of the call. If you want, you can

use the 

SetWSSrdHandler

 function to install an alternate handler.

DefaultWSSwrtHandler

 is the default handler for the 

WSSwrt

interrupt, which 

InitVXIlibrary

 automatically installs when it

initializes the NI-VXI software. When 

WSSwrt

 reaches the specified

count or an error occurs, it calls the 

WSSwrt

 interrupt handler with the

status of the call. The default handler sets the global variables

WSSwrtDone

, 

WSSwrtDoneStatus

, and 

WSSwrtDoneCount

. You can

use the variable 

WSSwrtDone

 to poll until the operation is complete.

Afterwards, you can inspect 

WSSwrtDoneStatus

 and

WSSwrtDoneCount

 to see the outcome of the call. If you want, you

can use the 

SetWSSwrtHandler

 function to install an alternate

handler.

In response to a Word Serial Protocol Error, the application should call

GenProtError

 to generate the error. Generating the error consists of

preparing the response to a future Read Protocol Error query (saving
the value in a global variable) and setting the ERR* bit in the local
Response register. The 

RespProtError

 function actually generates

the response when the Read Protocol Error query is received later.

GetWSScmdHandler

 returns the address of the current 

WSScmd

interrupt handler function. While Word Serial operations are enabled,
the 

WSScmd

 interrupt handler is called whenever a Word Serial

command (other than BREQ and BAV) is received.