I have been interested in calculators for long time. When I was young I wished to have programmable calculator like TI58/59 was. Unfortunately this wasn't easily affordable in our country. As I grew up I used some Casio programmable calculators, but I always was interested in TI-58/59. After so long time I returned to this old calculator having possibility to explore one TI-58.
It took quite long time to collect all available information for this calculator starting with U.S. patents through manuals to various "emulators" - as I could recognize, these were functional emulators only which emulate functions, not real hardware. So they don't behave exactly like real calculator - in good and bad meaning.
After I found article about microcode simulation I got an idea to use powerful MCU to monitor TI-58's signals and to try reading all ROM content. It is provided with one of patents but is not readable enough to use it for further work. By the time I was working with STM32F4 running up to 168MHz which is fast enough to do such task and has enough RAM to store all results.
After I had this ROM dump I found one man who had been looking for this ROM. I tried to ask him for cooperation and after short time first emulator was working.
I have continued my examinations and here is all what I have collected: