22 May
2006
22 May
'06
7:11 a.m.
On 5/21/2006 at 12:08 PM Chris M wrote:
AFAICG the 1770 is a double sided controller chip,
being that its used in the RE Robot brain-board.
Purchance is it pin compatible with the dopier LOL
1771?
Not close at all--the 1770's a 28 pin DIP; the 1771's a 40 pin package.
The 1791 and 2791 are very close to the 1771, but the '91 requires an
external data separator and the 2971 requires a few external components to
enable the internal data separator.
The 1770/1772/1773 are nice chips, but all lack a side select and support
only a single drive with their motor control logic. Still, if I had to
stay with WD 17xx type parts and 5.25" 360K drives, these are the chips
that I'd use. OTOH, if I had to also support 8" and 5.25" and 3.5" HD
drives, I'd use the 2971.
A National 8477 would a good choice for a build-it-yourself
controller--supports 4 drives, all common datarates, has drive polling, and
MFM as well as FM. Using one of these, your floppy controller would be
little more than the 8477, address decoding and some drive interface
buffering.
Cheers,
Chuck