LC51024MV-52F484C Lattice, LC51024MV-52F484C Datasheet - Page 4

• Manufacturer Part Number: LC51024MV-52F484C
• Manufacturer: Lattice

Lattice Semiconductor
Cascading For Wide Operation
In several modes it is possible to cascade adjacent MFBs to support wider operation. Table 2 details the different
cascading options. There are chains of MFBs in each device which determine those MFBs that are adjacent for the
purposes of cascading. Table 3 indicates these chains. The ispXPLD 5000MX design tools automatically cascade
blocks if required by a particular design.
Table 2. Cascading Modes For Wide Support
Table 3. MFB Cascade Chain
SuperWIDE Logic Mode
In logic mode, each MFB contains 32 macrocells and a fully populated, programmable AND-array with 160 logic
product terms and four control product terms. The MFB has 68 inputs from the Global Routing Pool, which are
available in both true and complement form for every product term. It is also possible to cascade adjacent MFBs to
create a block with 136 inputs. The four control product terms are used for shared reset, clock, clock enable, and
output enable functions. Figure 3 shows the overall structure of the MFB in logic mode while Figure 4 provides a
more detailed view from the perspective of a macrocell slice.
Logic
FIFO
CAM
ispXPLD 5256MX
ispXPLD 5512MX
ispXPLD 5768MX
ispXPLD 51024MX
Mode
Device
Input Width. Allows two MFBs to act as a 136-input block.
Arithmetic. Allow the carry chain to pass between two MFBs.
Memory Width Expansion. Allows MFBs to be cascaded for greater width support.
Memory Width Expansion. Allows up to four MFBs to be cascaded for greater width support.
A → B → C → D
H -> G -> F -> E
A → B → C → D → E → F → G → H
P → Ο → N → M → L → K → J → I
D → C → B → A → X → W → V → U → T → S → R → Q
E → F → G → H → I → J → K → L → M → N → O → P
H → G → F → E → D → C → B → A → AF → AE → AD → AC → AB → AA → Z → Y
I → J → K → L → M → N → O → P → Q → R → S → T → U → V → W → X
Cascading Function
4
MFBs in Cascade Chain
ispXPLD 5000MX Family Data Sheet