Interrupt Functions

The following functions are available to manage wRTOS interrupt services:

Attaching Function

RtAttachInterrupt can attach an Interrupt Service Thread (IST) and/or an Interrupt Service Routine (ISR) to a specified interrupt. Interrupts may be either line-based or message-based (MSI/MSI-X). You can also share interrupts exclusively attached within the RTSS environment with this call. Under Windows, only line-based interrupts are supported.

RtReleaseInterrupt releases an interrupt previously attached with RtAttachInterrupt.

RtGetPciMsixFreeMessages returns a PCI device’s MSI-X free messages (the MSI-X table entries available for attaching messages).
RtQueryProcessorVectorFreeCount queries the number of RTSS processor vectors (Interrupt Descriptor Table vectors) currently available for attaching interrupts.
RtQueryPciMsiCapability allows a user to query a PCI device and determine if the device has MSI or MSI-X capability. RtQueryPciMsiCapability is only supported in the RTSS environment.
RtDisableInterrupts, under the Windows environment, disables interrupt handling for all interrupts attached to a process. In the RTSS environment, all interrupts are disabled at the processor level.
RtEnableInterrupts enables all interrupts disabled by RtDisableInterrupts.

As with any thread, an interrupt thread can be preempted at any time by a thread that runs at a higher thread priority level.
IRQ affinity is set at the attach time.
Time slicing affects the execution of ISTs if there is a time quantum set for the IST.
To mask timer interrupts, use RtDisableInterrupts.