5–12
Chapter 5: IP Core Architecture
PCI Express Avalon-MM Bridge
Stratix V Hard IP for PCI Express
June 2012
Altera Corporation
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Control Register Access (CRA) Slave Module—This optional, 32-bit Avalon-MM
dynamic addressing slave port provides access to internal control and status
registers from upstream PCI Express devices and external Avalon-MM masters.
Implementations that use MSI or dynamic address translation require this port.
The CRA port supports single dword read and write requests. It does not support
bursting.
Figure 5–6
shows the block diagram of a full-featured PCI Express Avalon-MM
bridge.
Figure 5–6. PCI Express Avalon-MM Bridge
Transaction Layer
PCI Express
Tx Controller
PCI Express
Rx Controller
Data Link Layer
Physical Layer
PCI Express MegaCore Function
Tx Slave Module
Control & Status
Reg (CSR)
Sync
Avalon Clock Domain
PCI Express Clock Domain
Rx Master Module
Rx Master Module
PCI Express Avalon-MM Bridge
System Interconnect Fabric
PCI Link
CRA Slave Module
Address
Translator
Avalon-MM
Tx Read
Response
Avalon-MM
Tx Slave
Avalon-MM
Rx Read
Response
Avalon-MM
Rx Master
MSI or
Legacy Interrupt
Generator
Control Register
Access Slave
Address
Translator