On Tue, 29 May 2001, Andy N1YEW wrote:

> sure it has enough pins ya just gotta use a 688 as a address comparator and
> an 8 bit bus latch :-)

Sorry, I miss the point, why to to with a pic when is much cheaper with
one address comparator or a gal16V8 for address decoding and an usual
ls245 or ls373. Or if you need more pins, a fast 8255.
Using pic16F84 and some other components have nonsens ( my opinion...)
See my site:
http://www.geocities.com/vsurducan/8255.htm
Vasile



>
> andrew -- i was gonna make a isa programmer but i shelved it
> ----- Original Message -----
> From: "Jim Robertson" <newfound@PIPELINE.COM.AU>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Tuesday, May 29, 2001 6:40 AM
> Subject: Re: [PIC]: 8bit Data bus using a PIC16F84A.. is it possible.
>
>
> > At 01:40 PM 29/05/01 +0300, you wrote:
> > >On Tue, 29 May 2001, Dylan Hillier wrote:
> > >
> > >> <sorry, forgot to put a subject.. haaahaahaha.>
> > >>
> > >  don't laugh please, James will be angry...
> > >
> > >
> > >>
> > >> Im hoping to use a PIC16F84A to do this with PortA as the
> address/control
> > >> bus and port B as the data bus.
> > >> I would like to ability to control up to 8 devices using the bus by
> simlpy
> > >> connecting them to the bus, much the same way as you would with an
> Device
> > >> Card in an ISA bus on a 'old school' PC.
> > >>
> > >  Prototype reserved area for standard PC is 300H...31FH.
> > >You need some requirements:
> > >-- highZ for data signals
> > >-- address decoding pins, I think you can't do a full decode selection
> > >   only with porta
> > >-- WR and RD signals
> > >-- no interrupts ?
> > >-- ISA bus frequency less than 8MHz ( available in old PC ) or a good
> > >software and 40Mhz pic
> > >
> > >I think there are other pic microcontrollers which will fit better your
> > >requirements.
> > >
> > >Vasile
> >
> >
> > Yes, I agree. One option would be to use a 17Cxx chip and memory mapped
> > I/O. You could also wait for the Romless 18Cxx chip and do likewise.
> >
> > I don't see that the '84 has enough I/O to do this comfortably.
> >
> > -Jim
> >
> >
> >
> > >
> > >--
> > >http://www.piclist.com hint: The PICList is archived three different
> > >ways.  See http://www.piclist.com/#archives for details.
> > >
> > >
> > >
> > NEWFOUND ELECTRONICS
> > mailto:newfound@pipeline.com.au
> > http://www.new-elect.com
> > MPLAB compatible PIC programmers.
> >
> > --
> > http://www.piclist.com hint: The PICList is archived three different
> > ways.  See http://www.piclist.com/#archives for details.
> >
> >
> >
>
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.
>
>

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