15 Jun
2008
15 Jun
'08
1:43 p.m.
From: "Andrew Lynch"
Implementing floppy IO can take on many variations and
picking the FDC
is just the first of many challenges [FDC1793? NEC765? SMC9266?
WD2797?]. What about the data separator? Few chips remain and viable
sources are scarce. Even integrated FDCs with built in data separators
are not readily available.
The WD1770/1772/1773 is still my favorite "almost no external
circuitry" chip, but they're getting harder to find, in spite of
being used on Atari and Commodore boxes. You don't need to buffer
the floppy interface and the things have integrated data separators--
and come in a 28-pin package.
I wonder if it might be practical to implement an FDC in a uC or even
a CPLD.
Common sense might be to use an IDE-interface floppy, such as a
Superdrive (again, getting scarce) or implement a USB UHCI to
interface to USB floppies (still easy to find). I shudder to think
at the effort and space required to implement a USB stack in Z80
code, however.
Cheers,
Chuck