MultiTrack Interconnect
can drive other R8 interconnects to extend their range as well as C8
interconnects for row-to-row connections. One R8 interconnect is faster
than two R4 interconnects connected together.
R24 row interconnects span 24 LABs and provide the fastest resource for
long row connections between LABs, TriMatrix memory, DSP blocks, and
IOEs. The R24 row interconnects can cross M-RAM blocks. R24 row
interconnects drive to other row or column interconnects at every fourth
LAB and do not drive directly to LAB local interconnects. R24 row
interconnects drive LAB local interconnects via R4 and C4 interconnects.
R24 interconnects can drive R24, R4, C16, and C4 interconnects.
The column interconnect operates similarly to the row interconnect and
vertically routes signals to and from LABs, TriMatrix memory, DSP
blocks, and IOEs. Each column of LABs is served by a dedicated column
interconnect, which vertically routes signals to and from LABs, TriMatrix
memory and DSP blocks, and horizontal IOEs. These column resources
include:
■
■
■
LUT chain interconnects within an LAB
Register chain interconnects within an LAB
C4 interconnects traversing a distance of four blocks in up and down
direction
■
■
C8 interconnects traversing a distance of eight blocks in up and
down direction
C16 column interconnects for high-speed vertical routing through
the device
Stratix devices include an enhanced interconnect structure within LABs
for routing LE output to LE input connections faster using LUT chain
connections and register chain connections. The LUT chain connection
allows the combinatorial output of an LE to directly drive the fast input
of the LE right below it, bypassing the local interconnect. These resources
can be used as a high-speed connection for wide fan-in functions from
LE 1 to LE 10 in the same LAB. The register chain connection allows the
register output of one LE to connect directly to the register input of the
next LE in the LAB for fast shift registers. The Quartus II Compiler
automatically takes advantage of these resources to improve utilization
and performance. Figure 2–10 shows the LUT chain and register chain
interconnects.
2–16
Stratix Device Handbook, Volume 1
Altera Corporation
July 2005
ALTERA [ ALTERA CORPORATION ]
