HP-25C Eumulator

[PANAMATIK]

(01-07-2015 09:54 PM)brouhaha Wrote:  

(01-07-2015 12:54 PM)Chris Chung Wrote:  The flickering should resemble the real thing. Eric's code follows the ACT unit to every single flag in the registers which included the display on/off and segment controls. And my code follows his code very closely.

Not 100% sure, don't have a really calculator to compare w/. It appears so when I compare w/ a youtube video.

In Nonpareil ("Eric's code"), I made a serious effort to simulate the instruction-cycle behavior of the HP ACT, including how the display is refreshed one digit per instruction cycle. I did not specifically compare for exact matching of the display flickering, so there might be some differences, though in casual use it seems about the same.

As far as I've seen, Chris has done an excellent job of faithfully adapting the code to the microcontroller.

With the parallel out 74HC164 it is not possible to simulate the exact display behaviour, because the original HP-25 segment driver activated not one digit at a time, but only one segment in one digit at a time. But the human eye cannot distinguish that. The new ACT, also based on "Eric's code", multiplexes the display very exactly and I cannot see any slightest difference.
Bernhard