IPR-PCIE/8 Altera, IPR-PCIE/8 Datasheet - Page 87

• Manufacturer Part Number: IPR-PCIE/8
• Description: IP CORE Renewal Of IP-PCIE/8
• Manufacturer: Altera
• Type: MegaCorer

Specifications of IPR-PCIE/8

• Software Application: IP CORE, Interface And Protocols, PCI
• Supported Families: Arria GX, Cyclone II, HardCopy II, Stratix II
• Core Architecture: FPGA
• Core Sub-architecture: Arria, Cyclone, Stratix
• Rohs Compliant: NA
• Function: PCI Express Compiler, x8 Link Width
• License: Renewal License
• Lead Free Status / RoHS Status: na
• Lead Free Status / RoHS Status: na

Specifications
Altera Corporation
December 2006
Notes for
(1) where n is the virtual channel number; For x1 and x4, n can be 0 - 3
(2) For x8, n can be 0 or 1
tx_credn[65:0]
(1)
tx_errn
(1)
Table 3–24. Advanced Data Phase Signals
,
(2)
Signal
Table 3–24
O
I
I/O
Transmit credit. This signal is used to inform the application layer whether it can
transmit a transaction layer packet of a particular type based on available flow control
credits. This signal is optional because the MegaCore function always checks for
sufficient credits before acknowledging a request. However, by checking available
credits with this signal, the application can improve system performance by dividing
a large transaction layer packet into smaller transaction layer packets based on
available credits or arbitrating among different types of transaction layer packets by
sending a particular transaction layer packet across a virtual channel that advertises
available credits. See
Once a transaction layer packet is acknowledged by the MegaCore function, the
corresponding flow control credits are consumed and this signal is updated 1 clock
cycle after assertion of
For a component that has received infinite credits at initialization, each field of this
signal is set to its highest potential value.
For the x1 and x4 MegaCore functions this signal is 22 bits wide with some encoding
of the available credits to make it easier for the application layer to check the
available credits.
In the x8 MegaCore function this signal is 66 bits wide and provides the exact
number of available credits for each flow control type. See
Transmit error. This signal is used to discard or nullify a transaction layer packet, and
is asserted for one clock cycle during a data phase. The MegaCore function will
automatically commit the event to memory and wait for the end of the data phase.
Upon assertion of
packet transmission by deasserting
This signal only applies to transaction layer packets sent to the link (as opposed to
transaction layer packets sent to the configuration space). If unused, this signal can
be tied to zero. This signal is not available in the x8 MegaCore function.
PCI Express Compiler Version 6.1
Table 3–22
tx_err
Table 3–25
tx_ack
, the application interface should stop transaction layer
for details.
.
for the bit detail.
Description
tx_dfr
and
PCI Express Compiler User Guide
tx_dv
.
Table 3–26
for details.
3–49