Stratix GX Architecture
In the Stratix GX architecture, connections between LEs, TriMatrix
MultiTrack
Interconnect
memory, DSP blocks, and device I/O pins are provided by the
TM
MultiTrack interconnect structure with DirectDrive technology. The
MultiTrack interconnect consists of continuous, performance-optimized
routing lines of different lengths and speeds used for inter- and intra-
design block connectivity. The Quartus II Compiler automatically places
critical design paths on faster interconnects to improve design
performance.
DirectDrive technology is a deterministic routing technology that ensures
identical routing resource usage for any function regardless of placement
within the device. The MultiTrack interconnect and DirectDrive
technology simplify the integration stage of block-based designing by
eliminating the re-optimization cycles that typically follow design
changes and additions.
The MultiTrack interconnect consists of row and column interconnects
that span fixed distances. A routing structure with fixed length resources
for all devices allows predictable and repeatable performance when
migrating through different device densities. Dedicated row
interconnects route signals to and from LABs, DSP blocks, and TriMatrix
memory within the same row. These row resources include:
■
■
■
■
Direct link interconnects between LABs and adjacent blocks.
R4 interconnects traversing four blocks to the right or left.
R8 interconnects traversing eight blocks to the right or left.
R24 row interconnects for high-speed access across the length of the
device.
The direct link interconnect allows an LAB, DSP block, or TriMatrix
memory block to drive into the local interconnect of its left and right
neighbors and then back into itself. Only one side of a M-RAM block
interfaces with direct link and row interconnects. This provides fast
communication between adjacent LABs and/or blocks without using
row interconnect resources.
The R4 interconnects span four LABs, three LABs and one M512 RAM
block, two LABs and one M4K RAM block, or two LABs and one DSP
block to the right or left of a source LAB. These resources are used for fast
row connections in a four-LAB region. Every LAB has its own set of R4
interconnects to drive either left or right. Figure 4–8 shows R4
interconnect connections from an LAB. R4 interconnects can drive and be
driven by DSP blocks and RAM blocks and horizontal IOEs. For LAB
interfacing, a primary LAB or LAB neighbor can drive a given R4
interconnect. For R4 interconnects that drive to the right, the primary
LAB and right neighbor can drive on to the interconnect. For R4
interconnects that drive to the left, the primary LAB and its left neighbor
Altera Corporation
February 2005
4–11
Stratix GX Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
