I also have alawys wondered at the concept behind the crossbar on SiLabs parts. At first pause it seems like a good idea but once you get under the shirt one realizes it mostly just complicates the usage of the part.

For the crossbar to have been truly useful it should have been a true X/Y cross point switch matrix. What Cygnal gave us was a bizzare mechanism that allows a series of I/O functions to be assigned to a series of I/O pins which needs to be commited to before PC board artwork. I can only guess at the original plans at Cygnal wherein the first chips may have been intended to have full cross point switch. However the chip designers probably said "You want a 64x64 cross point matrix" ??## Forget it.

Michael Karas