Floppy controller questions

Allison ajp166 at bellatlantic.net
Wed Aug 24 08:08:38 CDT 2005

>Subject: Re: Floppy controller questions
>   From: Dave Dunfield <dave04a at dunfield.com>
>   Date: Tue, 23 Aug 2005 22:22:53 -0400
>     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>>That's what I wanted. I don't have any 8" drives, so adding support for them
>>is pointless. Ideally, I want a board that has a 6502-type interface on one
>>side and a 34-pin IDC connector on the other, with support for most common FM
>>and MFM 3.5" and 5.25" formats.
>>I managed to get DMA-mode transfers working, but never managed to get polled-
>>mode or interrupt-mode transfers working. Guess I'll have to learn fast when
>>I start writing code to drive the FDC...
>I did polled drivers on the 09 and it worked well. One thing I did find was
>that I had to connect a select to the TC pin so that I could pulse it to end
>a transfer - I did not find a way to cleanly end a transfer in polled mode
>without TC. I can give you the 6809 driver code as well if you want it.

There is a way to stop the transfer with out TC.  When programming the FDC
command bytes for single sector transfer simply put that sector in as N and
also as EOT. Since the FDC stops reading at EOT it will stop after one sector.


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