Athanasios Gogos wrote:

> Could you please send me a rough schematic of the configuration you mentioned
>
> including any switching circuitry or multiplexed to be used. And finnaly
> which
> low-end PIC would that be possible to implement to.
>
> Thank you
> e-mail address: athanasios.gogos@ncl.ac.uk
>
> P.S. if I use,say, PIC16C54 as a master can I use different PICs as slaves?
> Caisson wrote:
>
> > > Van: Athanasios Gogos <athanasios.gogos@NCL.AC.UK>
> > > Aan: PICLIST@MITVMA.MIT.EDU
> > > Onderwerp: HELPIC
> > > Datum: dinsdag 9 februari 1999 2:48
> > >
> > > Hello,
> >
> > Hello Athanasios,
> >
> > > I want to interface on a master PIC a 4-digit LCD display and
> > > a 4x4 keypad and this node to communicate with two slave
> > > nodes(interfaced only with a 4 digit LCD) with a two wire I2C bus.
> > > The problem I came up with is By using the PIC16C5X family do not hane
> > > enough I/O lines to do that, and also I want to keep the external
> > hardware
> > >  to a minimum.
> > > Any sugestions on to which PIC should I use and if I have to use
> > > external circuitry how that can be done?
> > > Thank you in advance
> >
> > Use the LCD-module in 4-bit mode (using 4 data & 3 control) connected to
> > PortB.  Double-use the 4 outputs to the LCD-Module as outputs to your 4x4
> > Keypad. Use PortA.0 to 3 as inputs from your KeyPad (Pull-up's required).
> > Use PortA.4 as I2C Output (don't forget the Pull-up resistor !) and the
> > non-used line on port B as I2C Clock.
> >
> > Greetz,
> >   Rudy Wieser
> >
> > P.s.
> > Take care that the 4x4 KeyPad does not short-circuit the PIC-outputs when
> > multiple buttons are pressed ... (use Diodes in series with buttons or
> > driving lines)