Hacking the HP Easycalc 100?

[deetee]

Hi all!

The HP Easycalc 100 is a cheap ($10), small and lightweight HP calculator with the typical HP form factor. Unfortunately it has an AOL logic.

But the hardware has a good quality:
* Good keys (not the quality of more expensive models, but no rubber keys)
* Excellent LCD display (easy to read, 12 digits, some extra symbols)
* High quality solar panel (delivers at least 1.5 V from almost no office light)
* 1.5V backup battery cell

After opening the Easycalc (which reminds me on my WP34s) and removing the small square sticker I found three contacts which could be some kind of serial connection (see attached pictures and markers).

Unfortunately here ends my knowledge in electronics.

Now I wonder if it is possible to hack this device like the famous WP34s to change it to some kind of scientific RPN calculator.

Maybe it is not possible to establish a connection, maybe there is no way to flash the memory and maybe there is no compiler to write some software for this processor (what kind of processor this might be).

What do you think and what can I try else?

Thanks in advance and regards
deetee

[damaltor]

I do not think taht there is any chance. the pads you found are probably just vias to the other side of the board which happen to be in that particular space visible through the hole in the back. i qould rather guess that the processor in that unit is one of those cheap mask-rom, non-reprogrammable ones.