Hi, I use PIC16C74 and set the port D as input. But it behaves as output, eliminating all the input signals. The spec. says that they are schmitt trigger inputs. What are "schmitt trigger input"? How to make the port as a "regular" input? Thanks. Tony -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu