6–32
Chapter 6: IP Core Interfaces
Interrupts for Endpoints
Stratix V Hard IP for PCI Express
June 2012
Altera Corporation
Interrupts for Endpoints
describes the IP core’s interrupt signals for Endpoints. Refer to
for detailed information about all interrupt mechanisms.
Interrupts for Root Ports
describes the signals available to a Root Port to handle interrupts.
Table 6–9. Interrupt Signals for Endpoints
Signal
I/O
Description
app_msi_req
I
Application Layer MSI request. Assertion causes an MSI posted write TLP to be generated
based on the MSI configuration register values and the
app_msi_tc
and
app_msi_num
input ports.
app_msi_ack
O
Application Layer MSI acknowledge. This signal acknowledges the Application Layer's
request for an MSI interrupt.
app_msi_tc[2:0]
I
Application Layer MSI traffic class. This signal indicates the traffic class used to send the
MSI (unlike INTX interrupts, any traffic class can be used to send MSIs).
app_msi_num[4:0]
I
MSI number of the Application Layer. This signal provides the low order message data bits
to be sent in the message data field of MSI messages requested by
app_msi_req
. Only
bits that are enabled by the MSI Message Control register apply. Refer to
app_int_sts
I
Controls legacy interrupts. Assertion of
app_int_sts
causes an Assert_INTA message
TLP to be generated and sent upstream. Deassertion of
app_int_sts
causes a
Deassert_INTA message TLP to be generated and sent upstream.
app_int_ack
O
This signal is the acknowledge for
app_int_sts
. This signal is asserted for at least one
cycle either when the
Assert_INTA
message TLP has been transmitted in response to the
assertion of the
app_int_sts
signal or when the
Deassert_INTA
message TLP has been
transmitted in response to the deassertion of the
app_int_sts
signal. Refer to
and
for timing information.
Table 6–10. Interrupt Signals for Root Ports
Signal
I/O
Description
int_status[3:0]
O
These signals drive legacy interrupts to the Application Layer as follows:
■
int_status[0]: interrupt signal A
■
int_status[1]: interrupt signal B
■
int_status[2]: interrupt signal C
■
int_status[3]: interrupt signal D
serr_out
O
System Error: This signal only applies to Root Port designs that report each system error
detected, assuming the proper enabling bits are asserted in the
Root Control
register
and the
Device Control
register. If enabled,
serr_out
is asserted for a single clock
cycle when a system error occurs. System errors are described in the
3.0
in the
Root Control
register.