DiscFerret: First working hardware, firmware and microcode!

Philip Pemberton classiccmp at philpem.me.uk
Sat Oct 30 13:35:32 CDT 2010


On 30/10/10 17:26, Al Kossow wrote:
> If it's going to be an adapter, could you add holes for SA1000-style 8"
> drives (50pin/20pin cabling)?

I almost mistook that for a floppy drive until I looked it up on 
Bitsavers...!

I can't see any real reason why SA1000 support couldn't be added to the 
bridge-board. Looks like the only changes required would be:
   - An oscillator to generate the 3.6866us +/- 0.1% timing clock 
(270982 to 271524Hz, nominal 271253Hz). Although I have no idea what 
standard crystal frequencies could be used to generate that signal. The 
FPGA's PLL might be persuaded to do it, though, I'll have to check.
   - Two jumpers to disconnect the Timing Clock from the ST412/506 Data 
connector when these are not in use (or maybe just a second connector?)
   - A 50-pin connector for the SA1000 control cable

The extra cost probably isn't worth worrying about... though I might 
have to restrict drive selection to Drive 0 only in order to get enough 
I/O pins for head selection.

Thanks,
-- 
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/



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