Ideas for a simple, but somewhat extendable computer bus

Eric Smith spacewar at
Sun Nov 19 21:51:56 CST 2017

On Nov 19, 2017 7:18 PM, "allison via cctalk" <cctalk at> wrote:

The rest is the specific implementation.  What happens if the CPU is
1802 or something else that does not match the 6500 or 8080z80 models.

There is nothing that prevents either the serial or parallel arbitration
schemes from working with other processors.

In the case of the 1802, it would work easily for interrupts, but would
need some additional circuitry for DMA, because the 1802 doesn't include
any feature whereby another bus master can request that the 1802 surrender
control of the bus. Instead, the 1802 has a built-in single-channel DMA

That 1802 bus master problem exists for interfacing _any_ sort of bus
master to any 1802, and is totally independent of what kind of DMA
arbitration is chosen.

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