Lattice Semiconductor
Figure 2-20. Input Register Block1
CLKENABLE
Architecture
LatticeSC/M Family Data Sheet
Latch
CLKDISABLE
SDR Register/Latch Block
D-Type/
Latch
INDD
INCK
INFF
To
Routing
DI
(from
PURESPEED
I/O Buffer)
Delay
Block
Optional
Adaptive
Input
Logic2
DDR/Shift Register Block
• DDR
• DDR + half clock
• DDR + shift x1
• DDR + shift x2
• DDR + shift x43
• Shift x1
• Shift x2
• Shift x43
IPOS0
IPOS1
INEG0
INEG1
LCLKIN (ECLK/SCLK)
HCLKIN (ECLK/SCLK)
LOCK
RUNAIL
1. UPDATE, Set and Reset not shown for clarity
2. Adaptive input logic is only available in selected PIO
3. By four shift modes utilize DDR/shift register block from paired PIO.
4. CLKDISABLE is used to block the transitions on the DQS pin during post-amble. Its main use is to
disable DQS (typically found in DDR memory interfaces) or other clock signals. It can also be used
to disable any/all input signals to save power.
DCNTL[0:8]
(From DLL)
2-19