FFFF000000060001001277AA000000000058000000001001210000001-7EFF6EB60Â4800480228A0Á-1‚0Â2‚28A22AFFFF0‚‚10‚‚2‚00010000003A00000001067F40840‚‚2‚28A22A67F028E00027E228A200002000006850000000067F,Subject: Re: Hardware Project From: david@uow.edu.au (David Wilson) Date: Mon, Nov 16, 1998 21Ç32@ Message-id: dcross1@nospam.home.com (David Cross) writes: >If I understand what you're saying, you propose to replace three separate chips >(?) or groups of code with one chip, or more condensed code. >My question is: Was there a reason why this wasn't practical or possible, say, >10 years ago when the Apple // series was a going concern? Late vintage cards (eg Apple 1MB RAMCard (Slinky), HS SCSI etc) did use custom logic chips to save on all the glue chips that a typical design needs. The early Apple // cards (Disk II, Parallel Printer card) used 256byte ROMs which fitted perfectly into the CnXX space. Later cards (Super Serial Card etc) used 2KB ROM with external logic to map it into CnXX and C800..CEFF using the two selects IOSEL and IOSTB. Still later a 4KB ROM was used with half the chip in C800..CFFF and the other half used for the CnXX space - the code replicated 7 times - once for each slot. Until relatively recently home made designs would not have used programmable logic devices such as PAL/GAL or more complicated ones due to the cost of the programmers (and the chips as well) - not that many people would have even had an EPROM Programmer at home I would guess. So my idea was to program a GAL to cut the number of glue chips down from over five to about two (at least the chips that are common to any Apple // card). The other suggestion made was to replace all of them with a single PLD (44 pins or such like). -- David Wilson School of IT & CS, Uni of Wollongong, Australia david@uow.edu.au 00040000001000000003067A1681100050000000A000000020681000060000005C000000020ÁC310‚‚ÁFFFF0‚C00000 30ÂÁ ‚‚ÁA20‚‚ÁFFFF0‚900000 10ÂÁ ‚‚Á000700000018000000010‚20Â180‚Á0008000000970000000140,Geneva40,4030 10000900000015000000022‚FA22A2‚FA22A000A00000021000000022‚7FFFFFFF22A2‚7FFFFFFF22A000B00000005000000020Â000C000000160000000167F1EB‚D72D0‚1000F000000280000000050 11AE890C0‚ÂÁÂÁ‚‚ÁÂ00130000005E00000000DA91F8CE1C1D1E1F7F1B024,-.¦¹°­­.FFFF0FFFF0