Philip Pemberton wrote:
On 06/02/12 19:25, Tony Duell wrote:
>Quadrature-output mice are getting hard to find now,
...
And nobody seems to sell 3-button ball mice any more
(well, not now
optical mice are down to the ?5ea price band), so you can't exactly buy
one of those, remove the PS/2 controller and add a 74LS14 to make a
quadrature mouse.
I found a data sheet for one of the early HP mouse chips that
said you can! The optical mouse sensor chip had quadtrature
outputs in addition to (I think) a PS/2 interface. I may have
been old enough that it required an additional chip to add
sipport for a scroll wheel. Anyway, I have a couple of mice
with that chip in, and one day I'll get around to making
a quadrature "tail" to connect to (say) the Atari ST.
--
John Honniball
coredump at gifford.co.uk