Figure 5-40: Receiver Data Realignment Rollover
This figure shows a preset value of four bit-times before rollover occurs. The
rx_cda_max
signal pulses for
one
rx_outclock
cycle to indicate that rollover has occurred.
rx_inclock
rx_channel_data_align
rx_outclock
rx_cda_max
Deserializer
You can statically set the deserialization factor to x4, x5, x6, x7, x8, x9, or x10 by using the Quartus II software.
You can bypass the deserializer in the Quartus II MegaWizard Plug-In Manager to support DDR (x2) or
SDR (x1) operations, as shown in the following figure.
Figure 5-41: Deserializer Bypass
rx_in
IOE supports SDR, DDR, or non-registered datapath
LVDS Receiver
FPGA
Fabric
rx_out
Bit Slip
Deserializer
rx_inclock / tx_inclock
DOUT
DOUT
DIN
Fractional PLL
(LOAD_EN,
diffioclk)
2
10
3 (LVDS_LOAD_EN,
LVDS_diffioclk, rx_outclock)
diffioclk
rx_outclock
DIN
+
–
IOE
10
2
Note: Disabled blocks and signals are grayed out
The IOE contains two data input registers that can operate in DDR or SDR mode. In DDR mode,
rx_inclock
clocks the IOE register. In SDR mode, data is directly passed through the IOE. In SDR and DDR modes, the
data width from the IOE is 1 and 2 bits, respectively.
Receiver Mode in Cyclone V Devices
The Cyclone V devices support the LVDS receiver mode.
LVDS Receiver Mode
Input serial data is registered at the rising edge of the serial
LVDS_diffioclk
clock that is produced by the
left and right PLLs.
Altera Corporation
I/O Features in Cyclone V Devices
5-67
Deserializer
CV-52005
2014.01.10