Are the PIC I/O pins TTL or CMOS? The data sheets say that the PICs are CMOS, but it also says the I/O pins have a TTL buffer. Does this mean that I need to treat them strictly as TTL? What kind of situations can damage the I/O pins on a PIC? (aside from the case of voltages over Vdd and under Vss) If I set an output pin high when it is tied to ground, will it simply source 20mA without damaging the chip, or will it cause a short to Vdd and fry the chip? Thanks for your help. Nathan