joemu@nscpdc.NSC.COM (Joe Mueller) (11/29/86)
I just heard recently that C-A threw out their proposed "zorro standard" bus architecture and replaced it with another so it would be upward compatible with the new Amiga (code named Ranger). If this is true, it's no wonder that 3rd party developers are slow to come out with products for the Amiga. I have been considering a hardware project but after this change, I'm going to wait until Commodore stops saying "preliminary" when referring to a standard. I also heard that since C-A changed the bus, expansion boxes with a truly standard bus have been pushed back another couple of months. Can anyone at C-A comment on this?
daveh@cbmvax.cbm.UUCP (Dave Haynie) (12/03/86)
> Summary: Expansion box rumors > > I just heard recently that C-A threw out their proposed "zorro standard" bus > architecture and replaced it with another so it would be upward compatible > with the new Amiga (code named Ranger). If this is true, it's no wonder that > 3rd party developers are slow to come out with products for the Amiga. I > have been considering a hardware project but after this change, I'm going to > wait until Commodore stops saying "preliminary" when referring to a standard. > > I also heard that since C-A changed the bus, expansion boxes with a truly > standard bus have been pushed back another couple of months. > > Can anyone at C-A comment on this? Well, I'm Commodore Technology, not Commodore-Amiga, but that's news to me. You may be confusing the early expansion efforts with the later. When the Amiga was originally introduced, the Expansion architecture hadn't been completely finalized. As a result of this, a few early companies started to build expansion cards and boxes based on the 86 pin edge available on the side of the Amiga. The expansion architecture has been finalized, and its now based on two types of devices. Essentially, the Amiga differentiates between expansion boxes and the cards that fit in them. Each box has an 86 pin connector into it, and optional one out of it, and presents a maximum of 1 "F" type load on each pin. Cards that fit into the boxes, called "PICs", present a 100 pin edge connector and a maximum of 2 "F" type loads on each pin. Each PIC is also required to conform to the Amiga "Auto-Configuration" specification, which is essentially a standard way of defining what each board does and handling memory map collisions between two boards. This is necessary since each board is place in memory via software, as opposed to DIP switches as with something like an IBM PC. Commodore sells a book that explains this, called "Schematics and Expansion Specifications", which contains the Amiga schematics, expansion box schematic, sample PIC, all PAL equations, and a physical drawings to suggest physical configurations for all of this stuff. -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dave Haynie {caip,ihnp4,allegra,seismo}!cbmvax!daveh "Laws to supress tend to strengthen what they would prohibit. This is the fine point on which all the legal professions of history have based their job security." -Bene Gesserit Coda These opinions are my own, though for a small fee they may be yours too. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~