On 1/9/2012 6:31 AM, Bill Sudbrink wrote:
Josh Dersch wrote:
(Now I just have to figure out why I can't
get the FDC to write
floppies correctly...)
Which FDC? I've had trouble with the original 1793
controller chips
(the early programmed ones with the painted over window on top) going
bad on a couple of 16FDCs I have. Replacing with a newer hard programmed
plastic package chip and then recalibrating the data sep circuit solved
a bunch of problems. The 4FDCs tended to just be "twitchy". I think
there was a known problem with the controller chip used on them.
Right now I have both a 16FDC and a 64FDC to play with (one is on
loan). I'm using Dave Dunfield's RDOS transfer utilities to upload the
"INIT" software into RAM from a PC. From there I can initialize
floppies (single-sided, single-density), and this appears to work -- it
goes through all 40 sectors (5.25" drive) and the drive steps and no
errors are reported. Then INIT attempts to write the filesystem to the
drive and it fails (it's a "Home Error" on Track 0, Surface 0, Sector 8,
if I recall).
Ignoring that and using the RDOS utilities to attempt to write a disk
image fail similarly ("Err-H 34" IIRC).
I've tried a pile of different disks and three different floppy drives
-- a Tandon TM-100 (300 RPM), a modified 1.2M 5.25" drive that runs at
300RPM, and a standard 1.2M drive (360RPM) and all three fail in exactly
the same way. (I don't currently have an 8" drive I can wire up, I need
to build a cable...) I've also tried swapping the cable out, and both
the 16FDC and the 64FDC fail identically.
I'm wondering if there's some fundamental problem with my current set-up
that's causing issues here...
- Josh