CertusPro-NX SerDes/PCS Usage Guide
Preliminary
Technical Note
FPGA-TN-02245-0.81
© 2020-2021 Lattice Semiconductor
27
All rights reserved. CONFIDENTIAL
PCI Express Link Layer (x1 + x4)
MPCS x4
LMMI
TLP
UCFG
LMMI
MPCS
EPCS
FPGA Core
PCI Express PCS
PMA Controller
PMA (SERDES)
Channel 0
Rx
C
D
R
Tx
P
LL
PMA (SERDES)
Channel 1
R
x
C
D
R
Tx
P
LL
PMA (SERDES)
Chan nel 2
Rx
C
D
R
Tx
P
LL
PMA (SERDES)
Channel 3
R
x
C
D
R
Tx
P
LL
Figure 5.11. PMA Only Mode
Detailed Interface Descriptions
MPCS Interface
MPCS interface is accessible when SerDes/PCS is configured as MPCS mode. MPCS mode is designed for applications
other than PCIe or PMA Only modes.
shows the detailed MPCS interface descriptions. All the signals listed in
this table are per lane, and NL means the number of lanes.
Table 5.7. MPCS Interface
Port Name
I/O
Width
Description
Clock and Reset
mpcs_rx_usr_clk_i
In
NL
User interface Rx clock input.
mpcs_tx_usr_clk_i
In
NL
User interface Tx clock input.
mpcs_tx_pcs_rstn_i
In
NL
Active low signal used to reset the Tx path of MPCS module.
This signal must be released only when PMA has completed
calibration.
mpcs_rx_pcs_rstn_i
In
NL
Active low signal used to reset the Rx path of MPCS module.
This signal must be released only when PMA has completed
calibration.
mpcs_cc_ clk_i
In
NL
Input clock for Clock Frequency Compensation. CTC clock input.
mpcs_rx_out_clk_o
Out
NL
PCS Rx output clock.
mpcs_tx_out_clk_o
Out
NL
PCS TX output clock.
mpcs_perstn_i
In
NL
Fundamental reset. Triggers PCS auto calibration.
mpcs_clkin_i
In
NL
This low speed clock drives all calibration logic inside PMA
Controller. Connecting this clock port to mpcs_tx_out_clk_o is
recommended, and the recommended frequency range is
100-300 MHz. This clock should be stable and continuous after
power on.