National Instruments NI-VXI

Chapter 3 Software Overview

Normally, VXI/VME interrupts are automatically acknowledged when

enabled via the function EnableVXIint. However, if the interrupts

are not enabled and the assertion of an interrupt is detected through

some method (such as GetVXIbusStatus), you can use

AcknowledgeVXIint to acknowledge an interrupt and return the

status/ID value. If the controller parameter specifies an extended

controller, AcknowledgeVXIint specifies hardware on the VXI/VME

frame extender (if present) to acknowledge the specified interrupt.

AssertVXIint (controller, level, statusId)

AssertVXIint asserts a particular VXI/VME interrupt level on a

specified controller (embedded or extended) and returns the specified

status/ID value when acknowledged. You can use AssertVXIint to

send any status/ID value to the VXI/VME interrupt handler configured

for the specified VXI/VME interrupt level. AssertVXIint returns

immediately (that is, it does not wait for the interrupt to be

acknowledged). You can call GetVXIbusStatus to detect if the

interrupt has been serviced. Use DeAssertVXIint to unassert a

interrupt that had been asserted using AssertVXIint but has not yet

been acknowledged.

DeAssertVXIint (controller, level)

DeAssertVXIint unasserts the VXI/VME interrupt level on a given

controller that was previously asserted using the AssertVXIint

function. You can use AssertVXIint to send any status/ID value to

the VXI/VME interrupt handler configured for the specified interrupt

level. You can call GetVXIbusStatus to detect if the interrupt has

been serviced. Use DeAssertVXIint to unassert a VXI/VME

interrupt that had been asserted using AssertVXIint but has not yet

been acknowledged.

Note: Unasserting an interrupt may violate the VME and VXIbus specifications

if the interrupt has not yet been acknowledged by the interrupt handler.

DefaultVXIintHandler (controller, level, statusId)

DefaultVXIintHandler is the sample handler for VXI/VME

interrupts, which is installed when the function InitVXIlibrary is

called. If VXI/VME interrupts are enabled (via EnableVXIint), the

VXI/VME interrupt handler for a specific logical address is called. You

must first call RouteVXIint to route VXI/VME interrupts to the

callback handler (as opposed to the signal processing routine).