Visible to Intel only — GUID: nik1410564875452
Ixiasoft
Visible to Intel only — GUID: nik1410564875452
Ixiasoft
4.5. Interrupts for Endpoints when Multiple MSI/MSI-X Support Is Enabled
Application Layer logic must construct the MSI (MemWr) TLP and send it using the TX slave (TXS) interface. For designs supporting multiple MSI/MSI-X, use the signals described below. For designs using a MSI TLP, use the control register access (CRA) interface to read the MSI Capability registers. The MSI information is at address offsets 14'h3C24, 14'h3C28, 14'h3C54, and 14'h3C5C. The Bus Master Enable bit is at address 14h'3C00.
Signal |
Direction |
Description |
---|---|---|
MsiIntfc_o[81:0] | Output |
This bus provides the following MSI address, data, and enabled signals:
|
MsiControl_o[15:0] | Output |
Provides for system software control of MSI as defined in Section 6.8.1.3 Message Control for MSI in the PCI Local Bus Specification, Rev. 3.0. The following fields are defined:
|
MsixIntfc_o[15:0] | Output |
Provides for system software control of MSI-X as defined in Section 6.8.2.3 Message Control for MSI-X in the PCI Local Bus Specification, Rev. 3.0. The following fields are defined:
|
IntxReq_i | Input |
When asserted, the Endpoint is requesting attention from the interrupt service routine unless MSI or MSI-X interrupts are enabled. Remains asserted until the device driver clears the pending request. IntxReq_i instructs the Hard IP for PCI Express to send an Assert_INTA message TLP. The deassertion of IntxReq_i instructs the Hard IP for PCI Express to send a Deassert_INTA message. |
IntxAck_o | Output |
IntxAck_o of the Hard IP for PCI Express is connected to 1'b0 for Cyclone V and Arria V devices. |
The following figure illustrates the timing for deassertion of legacy interrupts. The deassertion of IntxReq_i instructs the Hard IP for PCI Express to send a Deassert_INTA message.