
IDT Transparent Switch Operation
PES32NT24xG2 User Manual
10 - 5
January 30, 2013
Notes
When a port is configured to generate INTx messages, only INTA is used. Note that the Interrupt Pin
register (INTRPIN) must be programmed accordingly.
The MSI capability structure associated with the upstream port’s PCI-to-PCI bridge function is not by
default part of the PCI capability structure linked-list located in the function’s configuration space. This
capability may be added to the capability structure linked-list by using the serial EEPROM, SMBus, or the
Root to unlock registers and setting the Next Pointer (NXTPTR) field in one of the linked capabilities to point
to the MSI capability structure.
Legacy Interrupt Aggregation
Each switch partition supports legacy PCI INTx emulation. Rather than use sideband INTx signals, PCI
Express defines two messages that indicate the assertion and negation of an interrupt signal. An
Assert_INTx message is used to signal the assertion of an interrupt signal and an Deassert_INTx message
is used to signal its negation.
Within each partition, the PES32NT24xG2 maintains an aggregated INTx state for each of the four inter-
rupt signals (i.e., A through D) at each port. The aggregation includes INTx interrupts generated by all
downstream ports of the partition, as well as INTx interrupts generated by the upstream port’s PCI-to-PCI
bridge, NT, and DMA functions. Figure 10.1 shows a logical diagram of the INTx aggregation for a sample
partition configuration. In this example, the downstream and upstream port PCI-to-PCI bridge functions are
configured to generate INTA interrupts, while the NT and DMA functions are each configured to generate
INTD interrupts.
As shown in Figure 10.1, the upstream port PCI-to-PCI bridge function re-maps the INTx interrupts from
the partition’s downstream ports (see Table 10.3 below), and logically “ORs” the INTA interrupt result from
the re-mapping logic with the INTA interrupt generated by the function itself. In addition, interrupt aggrega-
tion logic at the multi-function upstream port aggregates the INTx interrupts issued by each of the port func-
tions.
Figure 10.1 Logical Representation of INTx Aggregation
P2P Bridge
Upstream
Port
P2P Bridge
Downstream
Port
Re-Map Logic
NT Endpoint
DMA Endpoint
Virtual PCI Bus
INTA
INTB
INTC
INTD
Assert_INTx
Deassert_INTx
Assert_INTx
Deassert_INTx
Summary of Contents for PCI Express 89HPES32NT24xG2
Page 20: ...IDT Table of Contents PES32NT24xG2 User Manual x January 30 2013 Notes...
Page 24: ...IDT List of Tables PES32NT24xG2 User Manual xiv January 30 2013 Notes...
Page 28: ...IDT List of Figures PES32NT24xG2 User Manual xviii January 30 2013 Notes...
Page 56: ...IDT PES32NT24xG2 Device Overview PES32NT24xG2 User Manual 1 20 January 30 2013 Notes...
Page 100: ...IDT Switch Core PES32NT24xG2 User Manual 4 22 January 30 2013 Notes...
Page 128: ...IDT Failover PES32NT24xG2 User Manual 6 4 January 30 2013 Notes...
Page 148: ...IDT Link Operation PES32NT24xG2 User Manual 7 20 January 30 2013 Notes...
Page 164: ...IDT SerDes PES32NT24xG2 User Manual 8 16 January 30 2013 Notes...
Page 170: ...IDT Power Management PES32NT24xG2 User Manual 9 6 January 30 2013 Notes...
Page 196: ...IDT Transparent Switch Operation PES32NT24xG2 User Manual 10 26 January 30 2013 Notes...
Page 244: ...IDT SMBus Interfaces PES32NT24xG2 User Manual 12 40 January 30 2013 Notes...
Page 247: ...IDT General Purpose I O PES32NT24xG2 User Manual 13 3 January 30 2013 Notes...
Page 248: ...IDT General Purpose I O PES32NT24xG2 User Manual 13 4 January 30 2013 Notes...
Page 330: ...IDT Switch Events PES32NT24xG2 User Manual 16 6 January 30 2013 Notes...
Page 342: ...IDT Multicast PES32NT24xG2 User Manual 17 12 January 30 2013 Notes...
Page 344: ...IDT Temperature Sensor PES32NT24xG2 User Manual 18 2 January 30 2013 Notes...
Page 384: ...IDT Register Organization PES32NT24xG2 User Manual 19 40 January 30 2013...
Page 492: ...IDT Proprietary Port Specific Registers PES32NT24xG2 User Manual 21 44 January 30 2013 Notes...
Page 588: ...IDT NT Endpoint Registers PES32NT24xG2 User Manual 22 96 January 30 2013 Notes...
Page 710: ...IDT JTAG Boundary Scan PES32NT24xG2 User Manual 25 12 January 30 2013 Notes...
Page 743: ...IDT Usage Models PES32NT24xG2 User Manual 26 33 January 30 2013 Notes...
Page 744: ...IDT Usage Models PES32NT24xG2 User Manual 26 34 January 30 2013 Notes...