[Coco] Detecting Shift key.

[Arthur Flexser]

There is no ROM routine for that.  But you can check for the shift key just
as one can check for any other key being down:  you put a value into one of
the keyboard PIA addresses and check for a certain bit being clear in a
different address on the same PIA.  Three ML instructions.  The values
depend on the key's position (row and column) in the internal keyboard
matrix.  Perhaps someone else can give you more specific detail.  Note that
the Dragon keyboard matrix is different than the CoCo's, so the test for
the shift key may well differ on the two machines.

Art

On Wed, Sep 20, 2017 at 4:43 PM, Phill Harvey-Smith <afra at ramoth.org.uk>
wrote:

> Hi all,
>
> Is there ROM routine that I can use to detect the shift key being held
> down. The reason I want to do this is so that I can use it (in the next
> version of the DragonMMC firmware) to skip running the autoexec file if
> shift is held down, Like MSDOS did back in the day.
>
> Cheers.
>
> Phill.
>
> --
> Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !
>
> "You can twist perceptions, but reality won't budge" -- Rush.
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