Routing Structure
shown in Figure 7. Undedicated horizontal routing tracks are
used to route signal nets. Dedicated routing tracks are used
for the global clock networks, and for power and ground
tie-off tracks.
The ACT 3 architecture uses vertical and horizontal routing
tracks to connect the various logic and I/O modules. These
routing tracks are metal interconnects that may either be of
continuous length or broken into segments. Segments can be
joined together at the ends using antifuses to increase their
lengths up to the full length of the track.
Vertical Routing
Vertical tracks are of three types: input, output, and long.
Vertical tracks are also divided into one or more segments,
with each segment in an input track dedicated to the input of
a particular module. Each segment in an output track is
dedicated to the output of a particular module. Long
segments are uncommitted and can be assigned during
routing. Each output segment spans four channels (two above
and two below), except near the top and bottom of the array
where edge effects occur. LVTs contain either one or two
segments. An example of vertical routing tracks and segments
is shown in Figure 8.
Horizontal Routing
Horizontal channels are located between the rows of modules,
and are composed of several routing tracks. The horizontal
routing tracks within the channel are divided into one or
more segments. The minimum horizontal segment length is
the width of a module pair, and the maximum horizontal
segment length is the full length of the channel. Any segment
that spans more than one-third of the row’s length is
considered a long horizontal segment. A typical channel is
Module Row
HCLK
CLK0
NVCC
SIGNAL
Track
SIGNAL
(LHT)
Segment
|
|
|
|
|
|
|
HF
SIGNAL
NVSS
CLK1
Module Row
Figure 7 • Horizontal Routing Tracks and Segments
8