lx64eb Lattice Semiconductor Corp., lx64eb Datasheet - Page 6

• Manufacturer Part Number: lx64eb
• Description: High Performance Interfacing And Switching
• Manufacturer: Lattice Semiconductor Corp.

Lattice Semiconductor
The four data inputs to the 4:1 MUX come from the GRP. The output of this MUX connects to the output register. A
fast feedback path from the MUX to the GRP allows wider MUXes to be built. Table 2 summarizes the various MUX
sizes and delay levels.
Table 2. MUX Size Versus Internal Delay
Figure 3. ispGDX2 Family MRB
Control Array
The control array generates control signals for the 16 MRBs within a GDX Block. The true and complement forms
of 32 inputs from the GRP are available in the control array. The 20 NAND terms can use any or all of these inputs
to form the control array outputs. Two AND terms are combined with a NOR term to form Set/Reset and OE sig-
nals. Figure 4 illustrates the control array.
Signals
Global
Select
MUX
Control Array Signals
From GRP
To GRP
MUX Select
*Selected MRBs see Logic Signal Connection Table for details
4:1
Up to 16:1
Up to 64:1
Up to 188:1 (with ispGDX2-256)
4
Signals
Global
MUX Sizes
2-4
2
Control Array
GDX
4
2
FIFO Out*
Out_Reg(n-1)
Out_Reg(n+1)
from IN_Reg(n+1)
from IN_Reg(n-1)
S/R
CK
CE
from
from
Delay
S/R
6
CK
OE
CE
Levels of Internal GRP Delays
Global Resetb
Global Resetb
Three Levels
Four Levels
Two Levels
One Level
V
ClK
CE
D/L
CC
Reg/Latch
Set
V
CC
Input
CE
ClK
D/L
Set
Reg/Latch
CE
ClK
Reset
D/L
Reg/Latch
Set
Out
ispGDX2 Family Data Sheet
Q
Reset
OE
Reset
Q
Q
to IN_Reg(n-1)
to IN_Reg(n+1)
(FIFO, SERDES
or PLL)
Flags*
TOE
to Out_Reg(n-1)
to Out_Reg(n+1)