Altera Arria V Avalon-MM - Manual (Page 136)

Figure 9-11: Qsys Design Including Completer Only Single Dword Endpoint for PCI Express
Qsys System
PCI Express
Root Complex
PCIe Link
to Host
CPU
Avalon-MM
Interconnect
Fabric
Avalon-MM
Slave
Avalon-MM
Slave
Avalon-MM
Hard IP
for PCIe
Avalon-MM
Master RX
Interrupt
Handler
RX Block
TX Block
Completer Only Single DWord Endpoint
Qsys Component
.
.
.
Bridge
The above figure shows the that completer-only single dword endpoint connects to a PCI Express root
complex. A bridge component includes the Arria V Hard IP for PCI Express TX and RX blocks, an
Avalon-MM RX master, and an interrupt handler. The bridge connects to the FPGA fabric using an
Avalon-MM interface. The following sections provide an overview of each block in the bridge.
RX Block
The RX Block control logic interfaces to the hard IP block to process requests from the root complex. It
supports memory reads and writes of a single dword. It generates a completion with Completer Abort
(CA) status for read requests greater than four bytes and discards all write data without further action for
write requests greater than four bytes.
The RX block passes header information to the Avalon-MM master, which generates the corresponding
transaction to the Avalon-MM interface. The bridge accepts no additional requests while a request is
being processed. While processing a read request, the RX block deasserts the
ready
signal until the TX
block sends the corresponding completion packet to the hard IP block. While processing a write request,
the RX block sends the request to the Avalon-MM interconnect fabric before accepting the next request.
Avalon-MM RX Master Block
The 32-bit Avalon-MM master connects to the Avalon-MM interconnect fabric. It drives read and write
requests to the connected Avalon-MM slaves, performing the required address translation. The RX master
supports all legal combinations of byte enables for both read and write requests.
For more information about legal combinations of byte enables, refer to Avalon Memory Mapped
Interfaces in the Avalon Interface Specifications.
Related Information
Avalon Interface Specifications
9-20 RX Block
UG-01105_avmm
2014.12.15
Altera Corporation IP Core Architecture
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