Hi Rob,
Yes I have the Lattice design tools, yes its on topic, one because I say so, and two, its a glue chip for an 89C52 system. So there.I need 16 inputs latched into a Parallel-serial converter for the. Any input generates an interrupt to the '52, the latches should guarantee I miss nothing. Its for the opening mechanism for "my" telescope dome


Here are the details

I'm going to go and look at Charles's reference for a start. I have played with the development system this afternoon and it seems pretty straightforward.

Steve