CertusPro-NX SerDes/PCS Usage Guide
Preliminary
Technical Note
FPGA-TN-02245-0.81
© 2020-2021 Lattice Semiconductor
21
All rights reserved. CONFIDENTIAL
Express PCS block using the PIPE interface with up to 128-bit data width. The Link Layer block operates at the clock
frequency of 250 MHz, while the user interface is at 125 MHz in Gen1/Gen2 speed and 250 MHz in Gen3 speed. The
user interface, TLP interface, can be from 32 bits up to 128 bits wide depending on the core configuration. 32 bits of
the TLP interface is used for ×1 mode, 64 bits of TLP interface is used for ×2 mode, and 128 bits of the TLP interface is
used for ×4 mode.
PM
A
(S
ER
D
ES
)
Q
u
ad
PC
I E
xp
res
s
PC
S
Q
ua
d
PCI Express Link Layer Quad
PCI Express Link
Layer x1 Core
PCI Express Link
Layer x4 Core
Configuration
Space Registers
(x1 + x4)
Buff er
25
0
M
H
z
25
0 M
H
z f
o
r G
en
3
12
5 M
H
z f
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en
2/
G
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32 bits UCFG x4
32 bits TLP (x1)
64 bits TLP (x2)
128 bits TLP (x4)
32 bits LMMI x4
PM
A
C
on
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Figure 5.3. PCI Express Hard IP Architecture
Each PCI Express Link Layer Quad can be configured as x4 mode, x2 mode, x1 mode, x2_x1 mode and x1_x1 mode. In
x2_x1 mode, the Link Layer Quad can support two independent PCI Express applications, one in ×2 mode and the other
in ×1 mode.
describes the SerDes/PCS lane mapping details.
Table 5.4. PCI Express Link Layer Quad Lane Mapping
Mode Name
Description
×4
All 4 lanes are used.
×2
Lane 0 and Lane 1 are used.
×1
Lane 0 is used.
×2_×1
Lane 0 and Lane 1 are used for ×2.
Lane 3 is used for ×1.
×1_×1
Lane 0 and Lane 3 are used for ×1.
shows the PCI Express Link Layer block functional diagram. For more detailed information on CertusPro-NX
PCI Express features, function descriptions, and IP usage, refer to CertusPro-NX PCI Express Hardened IP Core User
Guide (FPGA-IPUG-
XXXXX
).