HP Classic Series Display Driver

[Harald]

(09-05-2016 06:30 PM)PANAMATIK Wrote:  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

I tried alternating between two different outputs to display the few combinations that are not possible such as all decimal points. But the display became far less bright.
Now I think you are displaying a couple of characters that way. But I didn't notice any change on brightness.Any idea why this is not visible?

I'll be eagerly waiting for news on your website or here

Cheers,
Harald