ProASIC
PLUS
Flash Family FPGAs
General Description
Routing Resources
The routing structure of ProASIC
PLUS
devices is designed
to provide high performance through a flexible four-
level hierarchy of routing resources: ultra-fast local
resources, efficient long-line resources, high-speed, very
long-line resources, and high performance global
networks.
The ultra-fast local resources are dedicated lines that
allow the output of each tile to connect directly to every
input of the eight surrounding tiles (Figure
The efficient long-line resources provide routing for
longer distances and higher fanout connections. These
resources vary in length (spanning 1, 2, or 4 tiles), run
both vertically and horizontally, and cover the entire
ProASIC
PLUS
device (Figure
Each tile can
drive signals onto the efficient long-line resources, which
can in turn access every input of every tile. Active buffers
are inserted automatically by routing software to limit
the loading effects due to distance and fanout.
The high-speed, very long-line resources, which span the
entire device with minimal delay, are used to route very
long or very high fanout nets. (Figure
The high-performance global networks are low-skew,
high fanout nets that are accessible from external pins or
from internal logic (Figure
These nets
are typically used to distribute clocks, resets, and other
high fanout nets requiring a minimum skew. The global
networks are implemented as clock trees, and signals can
be introduced at any junction. These can be employed
hierarchically with signals accessing every input on all
tiles.
L
L
L
L
Inputs
L
Output
L
Ultra-Fast
Local Lines
(connects a tile to the
adjacent tile, I/O buffer,
or memory block)
L
L
L
Figure 2-1 •
Ultra-Fast Local Resources
v5.9
2-1
ACTEL [ Actel Corporation ]
