|HP-35, HP-65 .... reverse engineering latest news|
Message #1 Posted by Jacques Laporte on 19 July 2007, 12:02 p.m.
What's new on my site ?
- I started the HP-65's ROM exploration. A Java simulator is already running the HP-65 micro-code without problem, allowing to study how the program storage circuit is working ; its program memory symbolic addressing and its hardware label-searching mechanism are very original. http://www.jacques-laporte.org/sim65.htm
- The reverse engineering of the power units for the Classic (HP-35; HP-45) and Woodstock series (HP21, HP25) is published.
This job has been completed with the precious help of Daniel WEED - ex-rocket scientist from Phoenix, AZ. Dan did a nice job deconstructing the power unit of the HP-45 and repairing one unit with modern discrete composants.
- January 2007, I started to publish the HP-35 hardware pages. It is a kind of "black box" reverse engineering: you can't open a chip to see what's going on inside. But I had input and output signal traces on my scope and in mind the 1972 state of the art (sometimes though it is hard to follow, because of HP ingenuity for example the way they mixed PMOS chips and TTL logic, or the efficient inductive drive technique used for the LED display is great art!
- The HP 35 ROM Mapping is finally on line (a very hard work) : "The HP-35 firmware decoded & other mysteries".
Enjoy and please give feedback.
Edited: 20 July 2007, 5:10 a.m. after one or more responses were posted