Lack of a programmer for the GAL and lack of board space for the = discreets. Also lack of local inventory for either. James Newton (PICList Admin #3)=20 jamesnewton@piclist.com=20 1-619-652-0593 Vasile Surducan wrote on 01-5-29 22:29: 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" 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=20 ************************* This message has been truncated. The entire message is available on your = desktop e-mail client. =20 -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu