peter@sugar.UUCP (Peter da Silva) (11/19/87)
How about adding an extra 8 bits of address and 16 of data on a secondary bus in a similar fashion to the PC/AT bus? If you do it right it will be possible to use 16-bit cards in the new bus. Much simpler than going to NuBus. Of course NuBus has some very nice features. As has VMEbus. There might be form-factor problems, though (though not with Zorro I, oddly enough). A side question: since NuBus slots are at fixed addresses, is it technically a bus? -- -- Peter da Silva `-_-' ...!hoptoad!academ!uhnix1!sugar!peter -- Disclaimer: These U aren't mere opinions... these are *values*.
daveh@cbmvax.UUCP (Dave Haynie) (11/20/87)
in article <1079@sugar.UUCP>, peter@sugar.UUCP (Peter da Silva) says: > Keywords: Commodore A3000 Do it RIGHT! > > How about adding an extra 8 bits of address and 16 of data on a secondary > bus in a similar fashion to the PC/AT bus? If you do it right it will > be possible to use 16-bit cards in the new bus. Much simpler than > going to NuBus. Sure we can do something like that, and probably will. But that's just the obvious thing. There are other issues to address in an advanced expansion bus, like speed, multiple masters and DMA fairness, etc. Also bus specification; NuBus is very simple and clearly tells you when to do each and every thing; the current Amiga bus and the PC/AT bus are much more like extensions of the CPU and, being that CPU interfacing isn't necessarily designed to be extended as a bus, the bus interfacing on these busses is tricker for designers to do right. NuBus, VME, and MicroChannel all address these issues to some degree or another, though I'm not at all convinced that any one of them does it right (especially MicroChannel...). > A side question: since NuBus slots are at fixed addresses, is it technically > a bus? Sure. It's a geographically addresses bus. Makes much more sense in the case of a 4 gigabyte address space than it does in the case of a 16 megabyte address space. Amiga Autoconfig is the best way I've seen to configure cards in the latter case. > -- Peter da Silva `-_-' ...!hoptoad!academ!uhnix1!sugar!peter > -- Disclaimer: These U aren't mere opinions... these are *values*. -- Dave Haynie Commodore-Amiga Usenet: {ihnp4|caip|rutgers}!cbmvax!daveh "The B2000 Guy" PLINK : D-DAVE H BIX : hazy "I can't relax, 'cause I'm a Boinger!"