This is similar to decoding a matrix keypad but has the problem that it implicitly can have several "keys" pressed at the same time. Basically I've got some rotary switches which have a hex output - 4 bits. I'll have 3 switches and want to read them sequentially. Is there a smart way of reading them with only 7 pins (4c x 3r) ? Are there any dedicated chips out there that would do the same job ? I could of course dedicate a pic to be my decoder but would prefer not to go that route.

Andrew