28 Dec
2012
28 Dec
'12
3:11 p.m.
On Fri, Dec 28, 2012 at 09:00:12AM -0800, Al Kossow wrote:
I really did find a problem with the non-A version of
the 8473. I was using a
Seagate ST-01 and Imagedisk was having problems recognizing the address mark
on Track 0 of System/36 disks that went away when I switched to the AHA-1522
with a 8473A.
FWIW, I'm gradually working (3 prototype PCBs so far) on an ISA floppy
controller card which is basically an improved CompatiCard IV -- so, software
compatible with the NEC uPD765 (but actually an XMOS CPU), which is why it
needs to be an ISA card, and it can definitely handle 128 b/s and FM or MFM
using regular PC FDC software. Hopefully DEC RX02 too, plus there'll be
a raw mode that needs a special utility. Obviously it also has a 50-pin
connector for 8" drives.
If successful, it'll be a D Bit product, but either way the schematics/code
are on www.xcore.com as "ISAFLOP" (I need a better name!). The photo there
is out of date (Rev B, with bad hardware bugs and too many 34-pin connectors)
and the code can read single sectors OK but can't write anything and at least
the Compaq BIOS in my test PC doesn't recognize it as an FDC so it's failing
whatever the probing test is (so for now I use it as the secondary FDC). But,
FDCDEMO.COM can read sectors all day long so a lot *does* work.
John Wilson
D Bit