|Changing the ROM of a HP-35s?|
Message #1 Posted by Lode on 2 July 2011, 2:00 p.m.
Do you think it would be technically possible to change the ROM of a HP-35s?
The hardware of this machine rocks! Nice keys, low battery consumption, alphanumeric LCD, beautiful looks. The software on it is OK but is a bit disappointing imho. I think there should be more potential with this CPU and 30k memory. Like, for example, outputting '-1' instead of 'error' when pressing x^2 button if 'i' is on screen.
Is this ROM located under the same epoxy blob as the CPU? Is such a type of ROM typically modifiable somehow, and if it's truly hardwired read only, to replace it with something else somehow? I have much more software than electronics experience. It would be awesome to learn programming assembly for this CPU (or if there's a compiler for it it's even better) and applying this to the actual device to use it.
It would be fantastic to come up with something that uses roughly the same key layout but is better, and to have the ability to upload ROMs to it with USB from any OS including Linux.
Edited: 2 July 2011, 2:57 p.m.