HP Classic Series Display Driver

[PANAMATIK]

(09-05-2016 09:45 AM)Harald Wrote:  The classic display drivers can display any combination of segments you like. The only exception is the decimal point.

How does the woodstock display driver work in comparison? I assume it has a fixed character set? How is that transmitted to the driver?

Which other calculators do you have in mind for emulation? Currently I am planning to just output display data received from Tony's PIC controller. I have the feeling writing an emulator is way over my head..

The Classic display driver works obviously rather complicated. The Woodstock is made already much simpler. It receives an 8-bit serial code per digit from the ACT during the 56-bit data/instruction cycle, where only 4-bit are used for 15 characters plus space, and 1-bit for an additional decimal point. After 12 digits a display reset signal is issued to reset the shift register. The character set is very limited therefore and contains only the ten digits 0-9 and five alpha characters, usually E r o F P, to display "Error" and "OF" for overflow, P is not used.

The next emulation I'm preparing for, is never emulated before. It will be a little surprise and needs some weeks, or only days if I'm lucky.

Writing an emulator for classic or woodstock nowadays is relatively easy after Eric Smith has made his "nonpareil" publicly available. But teenix has done it by his own. Hats off.

Cheers Bernhard