[sebhc] list archive and a specific question

[Lee Hart]

steve shumaker wrote:
> One of the early 80's S100 books had a series of "notional" (for
> lack of a better term) interface circuits connecting the S100 to
> other busses available at the time. The H8 bus was included there.

My thought (without doing any research yet) is that all the Z-100 floppy
controller needs is the 8-bit data bus, a few address lines to select
the port addresses, the I/O read/write strobes, and an interrupt line.
That's a very small subset of the 100 pins.

The H8 bus has all these signals, though some "fiddling" will be needed.
For instance, S-100 uses separate data-read and data-write pins; the H8
combines them into a single 8-bit read/write bus.

The Z-100 board already uses the right controller chip, so the stock
Heath software is close to correct. Heath supplies source code for the
controller, so it should be straightforward to modify it if the I/O port
address or bit assignments within the port have changed.

It might be easier to go this route than to build a complete H37
soft-sector board for the H8. It also has the advantage that it would
support both 5.25" and 8" drives, like the CDR H8 disk controller.
-- 
*BE* the change that you wish to see in the world.
	-- Mahatma Gandhi
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net


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