Xilinx SelectIO 7 Series User Manual

7 Series FPGAs SelectIO Resources User Guide www.xilinx.com 161
UG471 (v1.10) May 8, 2018
Output Parallel-to-Serial Logic Resources (OSERDESE2)
Output Parallel-to-Serial Logic Resources (OSERDESE2)
The OSERDESE2 in 7 series devices is a dedicated parallel-to-serial converter with specific
clocking and logic resources designed to facilitate the implementation of high-speed
source-synchronous interfaces. Every OSERDESE2 module includes a dedicated serializer
for data and 3-state control. Both data and 3-state serializers can be configured in SDR and
DDR mode. Data serialization can be up to 8:1 (10:1 and 14:1 if using OSERDESE2 Width
Expansion). 3-state serialization can be up to 14:1. There is a dedicated DDR3 mode to
support high-speed memory applications.
Figure 3-13 shows a block diagram of the OSERDESE2, highlighting all the major
components and features of the block.
Data Parallel-to-Serial Converter
The data parallel-to-serial converter in one OSERDESE2 blocks receives two to eight bits of
parallel data from the fabric (14 bits if using OSERDESE2 Width Expansion), serializes the
data, and presents it to the IOB via the OQ outputs. Parallel data is serialized from lowest
order data input pin to highest (i.e., data on the D1 input pin is the first bit transmitted at
the OQ pins). The data parallel-to-serial converter is available in two modes: single-data
rate (SDR) and double-data rate (DDR).
The OSERDESE2 uses two clocks, CLK and CLKDIV, for data rate conversion. CLK is the
high-speed serial clock, CLKDIV is the divided parallel clock. CLK and CLKDIV must be
phase aligned. See OSERDESE2 Clocking Methods.
Prior to use, a reset must be applied to the OSERDESE2. The OSERDESE2 contains an
internal counter that controls dataflow. Failure to synchronize the reset deassertion with
the CLKDIV will produce an unexpected output.
X-Ref Target - Figure 3-13
Figure 3-13: OSERDESE2 Block Diagram
UG471_c3_13_111011
OCE
D1
D2
D3
D4
D5
D6
D7
OQ
OFB
D8
Data
Parallel-to-Serial
Convert
TCE
TBYTEIN
T1-T4
CLK
CLKDIV
RST
TFB
TBYTEOUT
TQ
3-State
Parallel-to-Serial
Converter
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Xilinx SelectIO 7 Series Specifications

General

Brand	Xilinx
Model	SelectIO 7 Series
Category	Computer Hardware
Language	English