At 10:07 AM 11/02/2002 +1100, you wrote:
>Hi Guys,
>
>I am just about to embark on my biggest PIC project to date. I am just in
>the hardware planning stages, and I am going to need every I/O available on
>the 40/44 Pin version.
>
>I have seen a lot of discussion on this list regarding RA4 being an "Open
>Drain" type.
>
>Can somebody please advise the concerns when using this pin - either as an
>input or an output and point out the traps and pitfalls that can be avoided.

No real difference if you are using RA4 as an input. "Open Drain" means that
when using the pin as an output, it can drive low but not high. When you set
RA4 high, it actually floats much like when set as an input. It you are driving
another logic input with RA4, you need to add a pull-up resistor (10K will do)
from RA4 to Vcc. This ensures that the pin will be pulled high when you set
it high. That's about it really.  :-)
Regards...

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu