[Coco] PS-2 Mouse on CoCo

[Torsten Dittel]

 From two earlier threads on interfacing "digtial" mice (search for 
"WICO" in the subject line):

For those interested here's a picture from the related patent file:

http://TRS-80.CC/WICO.png

V1,V2,H1,H2 is the digital 2-phase input for both x-y-directions from 
the photo sensors.