Custom hardware is faster and more compact than general-purpose
hardware. Integrated circuits (ICs) are the fastest and smallest
computing hardware, but they can only be customized for a
particular set of tasks, they require significant non-recurring
engineering (NRE) costs, and they quickly become obsolete.
For many applications, the cost of replacing obsolete ICs
Fortunately, technological developments have substantially
increased gate densities, making reconfigurable computers,
based on field programmable gate arrays (FPGAs), an attractive
alternative. An FPGA blurs the distinction between hardware
and software. The "hardware" fabricated by a foundry
is general purpose; consequently they are mass produced and
affordable. The logic of an FPGA is customized by loading
a "configuration," which is similar to a software
program. The resulting FPGA combines the best of both worlds.
It is faster and smaller than truly general-purpose hardware
such as a workstation, yet compared to an IC, it has smaller
NRE costs and transition costs, for it can be easily recustomized
without modifying the hardware by designing and loading a
different configuration. A reconfigurable computer could be
upgraded, or even reconfigured for a completely different
function, from a remote location.
Furthermore, reconfigurable computers can serve as powerful
research and development tools for sophisticated electronic
systems such as ICs and printed circuit boards. Simulation
tools for these systems do not always exist, and when they
do exist, they are not always capable of simulating large,
complex designs. In addition, prototype fabrication is expensive
and time consuming. A reconfigurable computer, on the other
hand, can serve as an affordable, fast, and accurate tool
for verifying electronic designs.
Tanner Labs Research and Development
Tanner Labs has developed three reconfigurable computers.
The first was for speech
recognition. The other two, for optical
processing and large neural
network processing, are even more flexible than a typical
reconfigurable computer because they are modular. They can
easily be adapted for other applications by designing a few
We plan to continue our reconfigurable computer research
and development by refining and enhancing our technology,
as well as by developing user-friendly configuration design
tools that enable the user to quickly and easily develop and
modify the logic using VHDL. In addition, we are using our
reconfigurable computer systems as research and development
tools for algorithm development and simulation.