Example Flow - Example Flow - 2026.1 English - UG1304

Versal Adaptive SoC System Software Developers Guide (UG1304)
Document ID
UG1304
Release Date
2026-06-23
Version
2026.1 English

The following flow is used by modules to trigger a event:

  1. Add the event index to the SsitEventIndex table in the xplmi_ssit.h file.
  2. Register the event with valid input arguments during boot using the XPlmi_SsitRegisterEvent() API.
  3. Trigger an event:
    1. To trigger a message event, form the request buffer with the command information and call the XPlmi_SsitWriteEventBufferAndTriggerMsgEvent() API.
    2. To trigger a notification event which does not have any data to be sent, call the XPlmi_SsitTriggerEvent() API with valid input arguments.
  4. Once the event is triggered, wait for an acknowledgment from the triggered secondary SLR using the XPlmi_SsitWaitForEvent() API.
  5. Once the event is acknowledged by the corresponding SLR, read the response using the XPlmi_SsitReadResponse() API. This step is applicable only for Message Events.
Note: If a message event is being triggered, then steps 3 to 5 are combined in a single API called XPlmi_SsitSendMsgEventAndGetResp().

The flow for when the event is triggered and the interrupt is generated to the corresponding SLR is as follows:

  1. The SSI technology interrupt handler checks for the pending event and calls the registered handler for the event.
  2. The handler must take care of acknowledging the event using the XPlmi_SsitAcknowledgeEvent() API. For message events, the XPlmi_SsitMsgEventHandler() handler takes care of writing the response and acknowledging the event after the command is handled.