We have reverse-engineered many projects, telcom, software, video
games, and printed circuit boards.
NEED
Due to the deregulation of the telephone industry, our
client had successfully reverse engineered many of the cards originally
produced by Western Electric for a SLC-96 T1 telephone system. However,
several cards were extremely difficult to reverse engineer as they had
many full-custom IC's, including a microprocessor, EPROM memory, and a
pair of gate arrays with over 10,000 gates each.
Additional requirements existed, including extreme
temperature range, reduced power, high reliability, and low cost of
manufacturing. Four different cards were required. The client required
that no custom IC's be used in the resulting design, and all components
had to be second sourced.
SOLUTION
Mitsi first developed a disassembler for the processor
code. By using a split screen editor, over 6,000 bytes of code were
translated into the target 68000 computer language.
During this development, a design flaw in the 68000
microprocessor was found and reported to the manufacturer. Mask changes
had to be made by the manufacturer to eliminate the problem.
The hardware was examined using logic analyzers, a
computer aided engineering workstation, and other tools. Simulated
circuits were tested against the known good circuits and modifications
made. Seventeen full-custom IC's were reverse engineered in this way.
A SLC-96 emulator was also developed. Controlled by a
PC, this emulator allowed worst case timing changes to be incorporated
in the design, and it reduced the need for the expensive and often
unavailable pair of SLC-96 systems.
A gate array emulator was developed and prototyped using
wire-wrap technology. After testing of the original card, four gate
array emulators were built and tested. The design was then extensively
simulated and a gate array produced that matched the functions required.
Altogether, 23 emulators were built and tested
individually and together. By using PLD technology, power was reduced,
the need for full-custom circuit was eliminated, and the design was
rapidly developed and tested.
RESULTS
All four cards are now in volume production. the gate
array was found to be 100% correct after the first pass. All of the
projects came in under budget and on time.
