pic microcontroller discussion list <> wrote:
> Nigel, thank you for your answer.  Are there 3V chips that
> include "or" and
> "and" gates?

There should be, have a look in catalogues!

> Also, I think I should be switching the AND gates and thr OR gates,
> shouldn't I?  I should feed the input to AND gate with the
> other input of each AND gate going to separate PIC pins.  Feed the two
> outputs of the AND gates into an OR, the output of the OR goes into the
PIC USART pin.

No.  Remember the TTL level signal idles high.  So to control the signal,
you need the other input to the logic gate to be able to force the output
high.  That's an OR gate.  Your solution would be correct if the TTL signal
idles low, but you need to invert all your logic.  You do that by changing
all your ANDs to ORs and ORs to ANDs.

Nigel
--
Nigel Orr, Design Engineer                 nigel@axoninstruments.co.uk
Axon Instruments Ltd., Wardes Road,Inverurie,Aberdeenshire,UK,AB51 3TT
               Tel:+44 1467 622332 Fax:+44 1467 625235
                   http://www.axoninstruments.co.uk

This e-mail and any files transmitted with it ("E-mail") is intended
solely for the addressee(s) and may contain confidential and/or legally
privileged information.  If you are not the addressee(s), any
disclosure, reproduction, copying, distribution or other use of the
E-mail is prohibited.  If you have received this E-mail in error,
please delete it and notify the sender immediately via our switchboard
or return e-mail.

Neither the company nor any individual sending this E-mail accepts any
liability in respect of the content (including errors and omissions)
and timeliness of the E-mail which arise as a result of transmission.
If verification is required, please request a hard copy version

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics