Thanks chaps,

I've worked around it by using some inputs on the Smoothstepper and some on the BOB.

Both Mach and the Smoothstepper have settings to use pins 2-9 as input and you set the PP to bidirectional mode. That way you get a total of 34 inputs from two PP's (42 if you use the Smoothsteppers).

Most probably I need a "smart PP BOB":D

Regards to all and thanks for the help.