[Coco] FDD 26 pin

Chester A Patterson vchester at setec-cr.com
Thu Aug 31 16:47:31 EDT 2006


Retaking the 26 pin Floppy Disk Drives adaptation. The two 720k FDD26
are set to 0 and 1 and are on a single cable. I made a nice little board
with a 26 pin connector to a 34 pin connector, with jumpers at the DSO
0/1/2 lines on the 34 connector to easily set the two FDD26 as either
0/1 or 1/2. It works great. BUT there is a strange behavior. The two
FDDs have a READY line, which I have left NC. If there is no disk in the
drive, then no amount of access will make the drive light come on, BUT
the motors will turn. I suspect it has something to do with the READY
line, but I am ignorant. The clincher though is that if I have disks in
both drives, and access D0, D0 light comes on AND, half a second later,
D1 light comes on as well! However, if I access D1 (with both drives
with disk) it works normally (only D1 light comes on) I have checked and
re-checked my wiring and all is well. What could it be? Thanks.



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