
Chapter : B–3
Descriptor/Data Interface
August 2014 Altera Corporation IP Compiler for PCI Express User Guide
In Figure B–2, the transmit and receive signals apply to each implemented virtual
channel, while configuration and global signals are common to all virtual channels on
a link.
Table B–1 lists the interfaces for this IP Compiler for PCI Express with links to the
sections that describe each interface.
Receive Datapath Interface Signals
The receive interface, like the transmit interface, is based on two independent buses:
one for the descriptor phase (
rx_desc[135:0]
) and one for the data phase
(
rx_data[63:0]
). Every transaction includes a descriptor. A descriptor is a standard
transaction layer packet header as defined by the PCI Express Base Specification 1.0a, 1.1
or 2.0, with two exceptions. Bits 126 and 127 indicate the transaction layer packet
group and bits 135:128 describe BAR and address decoding information. Refer to
rx_desc[135:0]
in Table B–2 for details.
Receive datapath signals can be divided into the following two groups:
■ Descriptor phase signals
■ Data phase signals
1 In the following tables, transmit interface signal names with an <n> suffix are for
virtual channel <n>. If the IP core implements multiple virtual channels, there is an
additional set of signals for each virtual channel number.
Table B–1. Signal Groups in the IP Compiler for PCI Express using the Descriptor/Data Interface
Signal Group Description
Logical
Descriptor RX “Receive Datapath Interface Signals” on page B–3
Descriptor TX “Transmit Operation Interface Signals” on page B–12
Clock “Clock Signals—Soft IP Implementation” on page 5–23
Reset “Reset and Link Training Signals” on page 5–24
Interrupt “PCI Express Interrupts for Endpoints” on page 5–27
Configuration space “Configuration Space Signals—Soft IP Implementation” on page 5–36
Power management
“IP Core Reconfiguration Block Signals—Hard IP Implementation” on
page 5–38
Completion
“Completion Interface Signals for Descriptor/Data Interface” on
page B–25
Physical
Transceiver Control “Transceiver Control Signals” on page 5–53
Serial “Serial Interface Signals” on page 5–55
Pipe “PIPE Interface Signals” on page 5–56
Test
Test “Test Interface Signals—Soft IP Implementation” on page 5–61
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