Johnathan Corgan wrote:
>
> I hope this isn't embarrasingly simple.
>
> I need to have a PIC port drive a signal, referenced to ground, at 5V or
> -5V, either sourcing or sinking up to 20 ma (per bit, 8 bits).


No isolation, but 2 cheap ideas for low chip count;
* use a CMOS 8 buffer chip good for 10v supply rails,
connect it between +5 and -5 rails.
* use a UCN5804 chip (8 darl drivers), and 8 pullup
resistors.
Obviously some resistors are needed for biasing etc
but resistors are cheap.
-Roman

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body