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.
