Lattice Semiconductor
ispMACH 4000V/B/C/Z Family Data Sheet
Table 5. Product Term Expansion Capability
Expansion
Chains
Macrocells Associated with Expansion Chain
(with Wrap Around)
Max PT/
Macrocell
Chain-0
Chain-1
Chain-2
Chain-3
M0 → M4 → M8 → M12 → M0
M1 → M5 → M9 → M13 → M1
M2 → M6 → M10 → M14 → M2
M3 → M7 → M11 → M15 → M3
75
80
75
70
Every time the super cluster allocator is used, there is an incremental delay of t
. When the super cluster alloca-
EXP
tor is used, all destinations other than the one being steered to, are given the value of ground (i.e., if the super clus-
ter is steered to M (n+4), then M (n) is ground).
Macrocell
The 16 macrocells in the GLB are driven by the 16 outputs from the logic allocator. Each macrocell contains a pro-
grammable XOR gate, a programmable register/latch, along with routing for the logic and control functions.
Figure 5 shows a graphical representation of the macrocell. The macrocells feed the ORP and GRP. A direct input
from the I/O cell allows designers to use the macrocell to construct high-speed input registers. A programmable
delay in this path allows designers to choose between the fastest possible set-up time and zero hold time.
Figure 5. Macrocell
Power-up
Initialization
Shared PT Initialization
PT Initialization (optional)
PT Initialization/CE (optional)
Delay
From I/O Cell
R
P
From Logic Allocator
To ORP
To GRP
D/T/L
Q
CE
Block CLK0
Block CLK1
Block CLK2
Block CLK3
Single PT
PT Clock (optional)
Shared PT Clock
Enhanced Clock Multiplexer
The clock input to the flip-flop can select any of the four block clocks along with the shared PT clock, and true and
complement forms of the optional individual term clock. An 8:1 multiplexer structure is used to select the clock. The
eight sources for the clock multiplexer are as follows:
• Block CLK0
• Block CLK1
7
LATTICE [ LATTICE SEMICONDUCTOR ]
