Altera Cyclone IV - Page 320

1–40 Chapter 1: Cyclone IV Transceivers Architecture
Transceiver Clocking Architecture
Cyclone IV Device Handbook, February 2015 Altera Corporation
Volume 2
When the byte serializer is enabled, the common bonded low-speed clock frequency is
halved before feeding to the read clock of TX phase compensation FIFO. The common
bonded low-speed clock is available in FPGA fabric as
coreclkout port, which can be
used in FPGA fabric to send transmitter data and control signals to the bonded
channels.
1 Bonded channel configuration is not available for Receiver Only channel operation
because each of the channels are individually clocked by its recovered clock.
Figure 1–38. Transmitter Only Datapath Clocking in Bonded Channel Configuration
Byte Serializer
8B/10B Encoder
Transmitter Channel PCS 3 Transmitter Channel PMA 3
Serializer
PCIe Hard IP
FPGA
Fabric
PIPE Interface
Tx Phase
Comp
FIFO
wr_clk rd_clk
wr_clk rd_clk
high-speed
clock
tx_dataout[3]
coreclkout
In 2 Bonded Channel Configuration
+
tx_coreclk[3]
Byte Serializer
8B/10B Encoder
Transmitter Channel PCS 2 Transmitter Channel PMA 2
Serializer
Tx Phase
Comp
FIFO
wr_clk rd_clk
wr_clk rd_clk
high-speed
clock
/2
/2
tx_dataout[2]
tx_coreclk[2]
Byte Serializer
8B/10B Encoder
Transmitter Channel PCS 1 Transmitter Channel PMA 1
Serializer
Tx Phase
Comp
FIFO
wr_clk rd_clk
wr_clk rd_clk
high-speed
clock
/2
tx_dataout[1]
tx_coreclk[1]
Byte Serializer
8B/10B Encoder
Transmitter Channel PCS 0 Transmitter Channel PMA 0
Serializer
Tx Phase
Comp
FIFO
wr_clk rd_clk
wr_clk rd_clk
high-speed
clock
/2
tx_dataout[0]
tx_coreclk[0]
In 4 Bonded Channel Configuration
+
/2
low-speed clock