Date   : Wed, 25 Aug 1999 06:16:02 -0700 (PDT)
From   : FARAZ CHOUDHRY <razzledazzler2@...>
Subject: Re: Mouse on the BBC

Better solution  -  8BS member DK5 (Ian Bell) has a load of AMX mice in
his loft.  Contact him and get one!

                                    F. H. Choudhry


--- Iain Williamson <Iain@...> wrote:
> In message <1EowVaAUCew3EwDX@...>
>           Stuart William McConnachie
> <stuart@...> wrote:
> 
> > In message <49363B1E5D%Iain@...>,
> Iain Williamson
> > <Iain@...> writes
> > >> Does any of you guys know how to connect a
> standard PC-mouse to the
> > >> user-port in order to use the AMX-software??
> (if at all possible?)
> > >
> [snip - AMX mouse]
> > >
> > >On the other hand if it plugs into the user port,
> it must have been a
> > >digital device; perhaps similar to a modern PS2
> mouse.
> >
> > Although digital in nature, the AMX mouse was a
> very low level device,
> > only signalling the BBC with an interrupt when the
> mouse moved (one
> > unit) and the direction it moved in.  It was the
> responsibility of the
> > BBC to count the number of movements in each
> direction and thus the
> > total distance travelled.  I believe the PC mouse
> interface is much more
> > complicated, with the PC mouse being a more
> intelligent, programmable,
> > device with a serial interface.
> 
> I believe the PS2 interface is similar; it sends
> simple framed serial data
> to the computer consisting of change in X, change in
> Y, button state (not
> neccessarily in that order). I can't remember if it
> does this constantly,
> or only when moved.
> > 
> > However, thinking about it, with a little work it
> might just be possible
> > to hack apart a PC mouse to provide the necessary
> signals for a BBC.
> 
> I wouldn't discount the possibility of making your
> own interface box; a
> chip to read the data from the mouse should be
> available off the shelf,
> and the other half should be the same as in an AMX
> mouse (i.e. the same
> bits you'd have to shove into a PC mouse under your
> scheme). You'd
> have to then interface those two bits. A similar
> amount of work, and a
> far neater solution, in all probability.
> 
> -- 
>   /""\          Iain Williamson
>  C  oo      Computer systems engineer 
>  _(  ^)
> /    ~\
> 

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