Post by thread:Unused I/O pins

Piclisters! My next question deals with unused PIC I/O pins. Should they be made either an input or output (software), left floating or tied to gnd or +5v? I am unfortunately using a 28 pin 16c63 dedicated to oscillating a single pin via hardware USART. Quick additional other question: Are there any other PICs available that have hardware USART? Cya- 6500 7000 Dave Celsnak ___7500 / / 8000 (Shift!) /-/ / / RPM / / / /

At 03:33 03/05/98 -0400, you wrote: >I am unfortunately using a 28 pin 16c63 dedicated to oscillating a single >pin via hardware USART. Quick additional other question: Are there any >other PICs available that have hardware USART? PIC16C74A does, as do many others. (And I'm not going to write them all down for you! Get a databook from your nearest distributor!) Regards Adrian WWW WWW Adrian Gothard WWW WW WWW White Horse Design WWWWWWWWWW +44-385-970009 (Mobile/SMS), +44-118-962-8913/4 (voice/fax) WWWW WWWW spam_OUTwhdTakeThisOuTzetnet.co.uk, http://www.users.zetnet.co.uk/whd --- Developers of GPS satellite-based tracking systems

At 03:33 1998-05-03 -0400, you wrote: >Piclisters! >My next question deals with unused PIC I/O pins. Should they be made >either an input or output (software), left floating or tied to gnd or +5v? As output. (Floating input may cause input cirquit to draw current if between high and low, and if you tie an input it might get damaged if there is any program error that makes it an output) /Morgan / Morgan Olsson, MORGANS REGLERTEKNIK, SE-277 35 KIVIK, Sweden \ \ .....mrtKILLspam@spam@iname.com, ph: +46 (0)414 70741; fax +46 (0)414 70331 /

>Piclisters! >My next question deals with unused PIC I/O pins. Should they be made >either an input or output (software), left floating or tied to gnd or +5v? I always make them outputs. This is more flexible than making them inputs, which would require tying them to one logic state or the other. Cmos inputs left unterminated can draw lots of power, and make transitions whenever they feel like it, (Just say no) Since the outputs don't have to be tied, it's marginally less expensive, and if I have an "oops" and need a pin, it's right there waiting for me :)