v3.0
3
eX Fam i l y FP G A s
e X Fa m i l y Ar ch i t ect u r e
The eX family architecture uses a “sea-of-modules”
structure where the entire floor of the device is covered
with a grid of logic modules with virtually no chip area lost
to interconnect elements or routing. Interconnection
among these logic modules is achieved using Actel’s
patented
metal-to-metal
programmable
antifuse
interconnect elements. Actel’s eX family provides two types
of logic modules, the register cell (R-cell) and the
combinatorial cell (C-cell).
The R-cell contains a flip-flop featuring asynchronous clear,
asynchronous preset, and clock enable (using the S0 and S1
lines) control signals (Figure 1). The R-cell registers
feature programmable clock polarity selectable on a
register-by-register basis. This provides additional flexibility
while allowing mapping of synthesized functions into the eX
FPGA. The clock source for the R-cell can be chosen from
either the hard-wired clock or the routed clock.
The C-cell implements a range of combinatorial functions
up to 5 inputs (Figure 2). Inclusion of the DB input and its
associated inverter function dramatically increases the
number
of
combinatorial
functions
that
can
be
implemented in a single module from 800 options in
previous architectures to more than 4,000 in the eX
architecture.
Mod u l e Or gani zat i on
Actel has arranged all C-cell and R-cell logic modules into
horizontal banks called Clusters. The eX devices contain
one type of Cluster, which contains two C-cells and one
R-cell.
To increase design efficiency and device performance, Actel
has further organized these modules into SuperClusters
(Figure 3 on page 4). The eX devices contain one type of
SuperClusters, which are two-wide groupings of one type of
clusters.
Figure 1 • R-Cell
Figure 2 • C-Cell
DirectConnect
Input
CLKA,
CLKB,
Internal Logic
HCLK
CKS
CKP
CLR
PSET
Y
DQ
Routed
Data Input
S0
S1
D0
D1
D2
D3
DB
A0
B0
A1
B1
Sa
Sb
Y