Emulating a smart CRT display unit - ideas?

Arno Kletzander Arno_1983 at gmx.de
Wed Aug 25 13:31:38 CDT 2010


Hello guys,

thanks for your quick replies!

"Chuck Guzis" <cclist at sydex.com> wrote:
> why not post a note to this guy:
> http://cncfanuc.blogspot.com/2009/04/fanuc-ac-servo-drive-system-
> failure.html
> Who seems to have a lot of information on his hands?

You're joking, right? I don't even get what this guy is writing about in most of his half-finished malformed sentences. Even if he was willing to help, it might be quite a challenge to get anything useful out of him.

> But you're going to need a fair level of detail on what actually goes 
> on over those 12 lines before you can get something going.

That's provided in that latest manual I got, down to bit-level detail, e.g.:

"Mode selection:"
A A A D D D D D D D D D
B B B B B B B B B B B B
2 1 0 8 7 6 5 4 3 2 1 0
-----------------------
0 0 1 1 x x 0 1 1 x x x   Set bit mode*
0 0 1 1 x x 0 1 0 x x x   Clear bit mode*
0 0 1 1 x x 1 1 1 x x x   Enable drawing by +/- H/V inputs*
0 0 1 1 x x 1 0 1 x x x   Clear screen (takes approx. 40 ms)

Operations marked * are latching and clear upon next selection."

Pages and pages of such codes.

> If you want a dedicated unit, an FPGA might still be your best bet, 
> if you have the skills (VHDL or Verilog).

No, I never learnt either of the above. OTOH, some LabView programming once again would be a nice change, and there is that FPGA toolkit for it that we were shown then.

> Alternatively, many faster 
> microcontrollers can directly generate video using nothing but 
> software.

Hey, that also sounds seriously interesting. Might be the cheapest and simplest approach since b&w doesn't need much of a DAC or anything. Alas the raster size doesn't map nicely to TV standards...

I'm also still all ears for comments on the "uC preprocesses, PC displays" idea.

Dave McGuire <mcguire at neurotica.com> wrote:
> I have a vague memory of doing a hack to an IBM PC CGA card that 
> enabled interlacing for a huge improvement in the readability of 
> character-based output.  It involved running a wire, and *I think* 
> replacing the 6845 with a 46505.  Does anyone else know about this?

This mode is not used here, the manual states that this display is non-interlacing.

Yours sincerely,
Arno Kletzander
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