ECP5 and ECP5-5G High-Speed I/O Interface
Technical Note
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FPGA-TN-02035-1.3
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Data_LoadN
Data_Move
Data_Direction
A
DELAYF
LOADN
MOVE
DIRECTION
CFLAG
Datain
Q[0]
Q[1]
Clkin
DLLDELD
Z
A
DDRDEL
LOADN
MOVE
DIRECTION
CFLAG
IDDRX1F
SCLK
D
Q0
Q1
RST
CLK
RST
UDDCNTLN
FREEZE
DDRDEL
LOCK
DDRDLLA
DCNTL[7:0]
Dcntl[7:0]
Clock_LoadN
Clock_Move
Clock_Direction
Clock_CFlag
Data_CFlag
7
Z
Primary
(optional)
DEL_MODE=SCLK_ALIGNED
STOP
DLL _LOCK
FREEZE
UDDCNTLN
DLL _RESET
DDR _RESET
SYNC_CLK
RST
UPDATE
Sync _ clk
sync_reset
Update
READY
(open)
RX_SYNC (soft IP)
S clk
Figure 5.4. GDDRX1_RX.SCLK.Aligned Interface (Dynamic Data/Clock Delay)
Interface Requirements
The clock input must use a PCLK input so that it can be routed directly to the DLLDELD input
You must set the timing preferences as indicated in the
Timing Analysis for High Speed DDR Interfaces
section.
5.3.
GDDRX2_RX.ECLK.Centered
Generic Receive DDR with the 2x gearing using Edge Clock Tree (ECLK). Input clock is centered to the input data. This
interface must be used for speeds above 400 MHz.
This DDR interface uses the following modules:
IDDRX2F element for X2 mode to capture the data
The incoming clock is routed to the Edge Clock (ECLK) clock tree through the ECLKSYNCB module.
CLKDIVF module is used to divide the incoming clock by 2 to generate the SCLK.
Static data delay element DELAYG to delay the incoming data enough to remove the clock injection time
Optionally, you can choose to use Dynamic Data Delay adjustment using DELAYF element to control the delay on
the DATA dynamically. DELAYF also allows you to override the input delay set. The type of delay required can be
selected through Clarity Designer.
DEL_MODE attribute is used with DELAYG and DELAYF element to indicate the interface type so that the correct
delay value can be set in the delay element.
The ECLKBRIDGE can be optionally enabled if the data bus is crossing over between the left and right sides of the
device. If ECLKBRIDGE is enabled, then the ECLKBRIDGECS element should be used in the interface before the
ECLKSYNCB element. This element can be enabled through Clarity Designer.
The startup synchronization soft IP (GDDRX_SYNC) is required for this interface to tolerate the skew between the
ECLKSYNCB Stop input and the Reset to the DDR and CLKDIV modules.
The following figures show the static delay and dynamic delay options for this interface.