CertusPro-NX SerDes/PCS Usage Guide
Preliminary
Technical Note
FPGA-TN-02245-0.81
© 2020-2021 Lattice Semiconductor
23
All rights reserved. CONFIDENTIAL
Four MPCS channels can work independently or together to compose multi-lane link. Each channel has one
independent PMA interface, one LMMI interface, and one FPGA fabric interface. The internal functional block diagram
of the channel is illustrated in
. Every Quad can be programed into one of the serval protocol-based modes.
Each Quad can be programmed with selected protocols that have the same reference clock source. For example, SGMII
channel and QSGMII channel can share the same Quad using the same reference clock. When a Quad shares a PCI
Express ×1 channel with a non-PCI Express channel, the reference clock for the Quad must be compatible with all
protocols within the Quad. For example, a PCI Express spread spectrum reference clock is not compatible with most
Gigabit Ethernet applications.
Since each Quad has its own reference clock, different Quads can support different standards on the same chip. This
feature makes the CertusPro-NX family ideal for bridging between different standards. MPCS Quads are not dedicated
solely to industry standard protocols. Each Quad and each channel within a Quad can be programmed for many
user-defined data manipulation modes. For example, word alignment and clock tolerance compensation can be
programmed for user-defined operation.
MPCS Channel
8B/10B PCS
64B/66B PCS
Data Path of PMA Only Mode
Channel
Registers
PMA
Controller
Fabric
Tx FIFO
&
Rx FIFO
Loopback FIFO
PMA Control Signal Sync
Figure 5.6. MPCS Channel Functional Block Diagram
Each MPCS channel has all the following functional blocks (
):
The 8B/10B PCS: Supports popular 8B/10B PCS-based packet protocols.
The 64B/66B PCS: Supports IEEE802.3 10GBASE-R protocol.
PMA-only mode: Allows user logic to access PMA with very low latency.
Channel register: Self-contained configuration and status register.
PMA Control Signal Sync: Synchronize PMA control signals between PMA controller and user logic.
Loopback FIFO: Internal FIFO for the corresponding loopback mode.
Tx FIFO and Rx FIFO: Transmitter FIFO and Receiver FIFO, which are used for gearing and clock phase difference
elimination.
However, in each quad, only lane 2 or lane 3 of the MPCS channel contains 64B/66B PCS. So Ethernet 10GBASE-R is
only supported by lane 2 and lane 3 of each quad, while other protocols can be supported by all lanes. Refer to
for more details. Lane 0 and lane 1 have no 64B/66B PCS path. So, related registers cannot be accessed by
user logic.