Lattice Semiconductor CertusPro-NX - PMA Clock Divider; Serdes;Pcs Reset; Figure 7.17. 64 B;66 B PCS Without Using GPLL (Case II); Table 7.6. Reset and Power Control Signals

CertusPro-NX SerDes/PCS Usage Guide
Preliminary Technical Note
FPGA-TN-02245-0.81 © 2020-2021 Lattice Semiconductor 85
All rights reserved. CONFIDENTIAL
Rx
Gear Box
Block
Aligner
De-
Scrambler
64B/66B
Decoder
Rx
FIFO
Tx
FIFO
64B/66B
Encoder
Scrambler
Tx
Gear Box
16b data
TX Path
RX Path
PMA
/4
/4
BER
Monitor
66b block
2b sync
+ 64b data
8b TXC
+ 64b TXD
8b TXC
+ 64b TXD
16b data
66b block
2b sync
+ 64b data
2b sync
+ 64b data
8b RXC
+ 64b RXD
8b RXC
+ 64b RXD
tx_pcs_clk
(644.5MHz,
from Tx PLL)
tx_pcs_divclk (161.1328MHz)
tx_usr_clk
(161.1328MHz)
tx_out_clk
(161.1328MHz)
rx_pcs_clk
(644.5MHz,
from Rx CDR)
rx_usr_clk
(161.1328MHz)
rx_out_clk
(161.1328MHz)
defaults
rx_pcs_divclk (161.1328MHz)
rx_pcs_buffclk (322.2656MHz)
/2
tx_pcs_bufclk (322.2656MHz)
/2
Fabric
Fabric
DFF
DFF
Figure 7.17. 64B/66B PCS without Using GPLL (Case II)
PMA Clock Divider
Inside the PMA Controller, two PMA clock dividers are implemented for Tx/Rx gearbox. The gearing can be 1:1, 2:1 or
4:1 for both Tx path and Rx path, with considerations below:
 PMA data width is 16-bit or 20-bit.
Gearing must be 1:1.
 PMA data width is 8-bit or 10-bit.
Gearing can be 1:1 or 2:1.
 PMA data width is 5-bit.
Gearing can be 1:1, 2:1, or 4:1.
These PMA clock dividers can be configured via IP GUI, primitive parameter or register accessing.
SerDes/PCS Reset
Reset and Power Control Signals
Table 7.6 shows the reset and power control signals for CertusPro-NX SerDes/PCS. NL represents the number of lanes.
Table 7.6. Reset and Power Control Signals
Port Name
Width
Description
Reset Signals
mpcs_tx_pcs_rstn_i
NL
Active low signal used to reset the Tx path of MPCS channel. Exists
only in MPCS mode.
mpcs_rx_pcs_rstn_i
NL
Active low signal used to reset the Rx path of MPCS channel. Exists
only in MPCS mode.
mpcs_perstn_i
NL
Fundamental reset. Triggers PCS auto calibration. Exists only in MPCS
mode.
epcs_tx_pcs_rstn_i
NL
Active low signal used to reset the Tx path of MPCS channel. Exists
only in PMA Only mode.
epcs_rx_pcs_rstn_i
NL
Active low signal used to reset the Rx path of MPCS channel. Exists
only in PMA Only mode.
epcs_rstn_i
NL
Fundamental reset that triggers PCS auto calibration. Exists only in
PMA Only mode.