I have both a 16FDC and a 64FDC (for the moment) and
right now I have
it wired to a single 5.25" drive (w/proper termination). I've tried
three different drives -- a Tandon TM-100, an unmodified 1.2M 5.25"
drive, and one that's modded to spin at 300rpm. Same exact behavior on
all three.
Are you attempting to format single or double sided? WHICH is your
TM-100?
Are you attempting to format 40 track or 80?
Although most 1.2M drives can be configured for 80 track DOUBLE (NOT
"HIGH"!) density, it adds additional unnecessary variables. 1.2M is the
WRONG drive for that FDC port.
It might be feasible to cable the 1.2 (or a 1.4M!) drive to the 8" port,
but don't even try until you get the "normal" stuff working.
When it "won't read", in what way? Is it failing to see sectors and
formatting? Or is it just unhappy with the directory structure and/or
"boot" sector?
There are numerous format variations possible with Cromemco. Most
[5.25"] have 10 sectors of 512 bytes per sector, and the index and data
gaps are "not easy" for a PC FDC to read. However, a disk formatted to
10 x 512 on a PC, with appropriate content in the "boot" sector is
readable by Cromemco, and solves SOME data interchange issues.