sure it has enough pins ya just gotta use a 688 as a address comparator and an 8 bit bus latch :-) andrew -- i was gonna make a isa programmer but i shelved it ----- Original Message ----- From: "Jim Robertson" To: 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: > > > >> > >> > > 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.