MultiTrack Interconnect
Clear & Preset Logic Control
LAB-wide signals control the logic for the register's clear and load/preset
signals. The ALM directly supports an asynchronous clear and preset
function. The register preset is achieved through the asynchronous load
of a logic high. The direct asynchronous preset does not require a NOT-
gate push-back technique. Stratix II devices support simultaneous
asynchronous load/preset, and clear signals. An asynchronous clear
signal takes precedence if both signals are asserted simultaneously. Each
LAB supports up to two clears and one load/preset signal.
In addition to the clear and load/preset ports, Stratix II devices provide a
device-wide reset pin (DEV_CLRn) that resets all registers in the device.
An option set before compilation in the Quartus II software controls this
pin. This device-wide reset overrides all other control signals.
In the Stratix II architecture, connections between ALMs, TriMatrix
memory, DSP blocks, and device I/O pins are provided by the 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.
MultiTrack
Interconnect
TM
DirectDrive technology is a deterministic routing technology that ensures
identical routing resource usage for any function regardless of placement
in 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 in 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
R24 row interconnects for high-speed access across the length of the
device
2–22
Altera Corporation
Stratix II Device Handbook, Volume 1
May 2007
ALTERA [ ALTERA CORPORATION ]
