|Re: HP67 Black Box (NNNs, etc.)|
Message #3 Posted by John Garza on 24 Feb 2007, 12:16 p.m.,
in response to message #2 by Geir Isene
Basically, there are sections of memory in the HP67 that cannot be accessed unless under certain conditions. You may have also noticed the calculator has limited alpha capability (Crd, Error, etc.). These characters can be assembled by the user to make strings of psuedo-alphanumerics. These are called Non-Normalized Numbers (NNNs for short). Much of the work done researching the HP67 NNNs later evolved into Synthetic Programming on the HP41C. It uses the old trick of moving the program pointer to the data area - so then you can "program" new data.
Anyone familiar with the TI-59 remembers how it can repartition program space vs. data registers. Same principle, the TI-59 just made it easier. I recall writing code on the 59 that would literally reprogram itself by storing data in registers, then repartitioning that data to be program lines and then executing them. But that's a tale for another group.
This device has 5 parts:
1. A plug that fits the power connector of the HP67
2. A black Mode Select button
3. A red Crash Recovery button
4. A coarse tuning knob (upper)
5. A fine tuning knob (lower)
To operate, you insert the plug in the HP67, switch the HP67 ON and in W/PRGM mode, and start hitting the Mode Select (black) button while tweaking the knobs. You're looking for a display of (000 84) or (99x 84). depending on which display you get, you can then proceed to entering keystrokes that you have devised to display the proper pseudo-alpha string (sometimes called a Word/Phrase/Graphic).
The box must be tuned to each HP67 and requires quite a bit of finesse and patience.
Although it's meant for use with the HP67 calculator, the NNNs produced can be written to a magnetic card and then displayed on an HP97. However, certain NNNs may burn out the HP97 print head when printed! So care must be taken.
Most of the original work in NNNs was done by Lou Cargile and others of the PPC club back in the 70's.