Have you heard of Centurion minicomputers?If it doesn’t, don’t be sad — neither do we, until [David Lovett] Stumbled upon the semi-complete version of the 1980 mini version, with all its wood trim and dust-wrapped glory. What did the hacker do with such an acquisition, but then tried to make it start again?
Of course, letting the Reagan administration’s machine run is not without risks, including the opportunity to lose everything on the machine’s many ROM chips forever. When it was found that commercial ROM readers supporting various chips proved difficult, [David] Decided to build your ownSince he has successfully read a chip in a commercial reader, this has made his job much easier, and this has provided him with a benchmark to compare his circuits. The hardware is very simple-a 12-bit counter built by three cascaded 74LS161s is used to step through the address, plus an Arduino Nano to provide clock pulses and read out the data to the serial port.
This circuit gives the same result as a known good read, which means that the result is valid for the rest of the chips. The breadboard setup makes it easy to support multiple ROM pin assignments, even for chips that use -9 volts. What does the data on the ROM mean, if any, is still a mystery, but at least it has been backed up now.
Before anyone notices the obvious, yes, [David] 555 could have been used to time the reader-maybe even this. We actually like it very much, but we understand-sometimes you just need to put an Arduino in your work to complete it.