Date   : Sat, 30 Jul 1994 12:29:40 +0100
From   : jfid@... (James Fidell)
Subject: Re: cursor behaviour

James Bonfield wrote:

> James Fidell writes:
> 
> >I've spent a couple of days (yes, really :-( trying to get my emulator to
> 
> At least someone's still doing some work on things! I haven't added any
> features to my emulator for MONTHS! Literally :-(
> 
> >That is, according to the manuals, write &20 into CRTC register 10.
> >
> >Why does this turn the cursor off ?
> 
> As far as I recall, without my 'guide with me, this register controls
> the size of the cursor. In which case &20 is setting it to size zero
> (ie turning it off).

It controls the blinking/non-blinking, blink rate and cursor start line
(in terms of scan lines) according to the AUG.  Writing &20 to this
location is documented as just changing the cursor blink rate and setting
the start line of the cursor to zero.

> >And, why, when you enter COPY mode, does the cursor re-appear as a block ?

Which is how the cursor appears when you enter COPY mode...

> This is almost certainly code performed by the OS. All we need to do
> is write an accurate 6845 (all!) and we shouldn't worry about quite
> what the OS is doing with it...

James.

-- 
 "Yield to temptation --             |
  it may not pass your way again"    |     jfid@...        
                                     |
        - Lazarus Long               |              James Fidell