Thank you for your reply! What I seem to have forgotten to mention in my original message was that I am a newbie who has bitten a graduate project involving PICs which I'm finding difficult to chew! In other words... I'm not quite sure i know how to implement (see program) your suggestion! Any directions, or where I could find anything similar in assembly? Many thanks in advance, Theodore ----- Original Message ----- From: "Vasile Surducan" To: Sent: Tuesday, March 19, 2002 10:20 AM Subject: Re: [PIC]: Communicating between 16F84 and 16F877 > My mind is resting on SPI. > > I'll try something similar, with clk, data and two chip > select. > The master will send a clk to the chip selected. The slave will respond > with 8 bit of data ( or more ) on any rising or falling clock edge. On the > same bus only selected chip will answer. For small distances up to 2.5...3 > meters no level converters are required if twisted wires are used ( > clk/gnd, data/gnd, cs/gnd ) > > best, Vasile > > P.S. From the tea rebellion at Boston, half of the world is speacking a > different english... so spelling correctly is like Einstein relativity > theorem... > > > > On Tue, 19 Mar 2002, T Vavouras wrote: > > > I have two 16F84 ('slaves') each reading an 8button keypad. > I configure portb of each PIC to read the input. > I need to send the 8bit input state to a 'master' (probably a 16F877) > once there is a change (a button is pressed or released). > Can i do it just using an RX and a TX line? how? > if not possible, what else do you suggest? > > many thanks > > > > -- > > 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 > > > > > > -- > 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 > > > -- 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