Intel 8272 based floppy controller & Missing Address Mark

[Chuck Guzis]

On 11/28/19 9:34 PM, David Kuder via cctalk wrote:
> After digging in the manual for the controller card, it appears they have set it up to only support single density FM formatting.  Even still, formatting the disk 568KB FM with either clock speed 8MHz or 4MHz (and 500KHz / 250KHz WCLK respectively), same outcome with missing address mark.  I think I’m going to scrap the floppy card and design a fresh one using the FDC37C78. Less things to go wrong.

Is there a manual for the card online?

If you're doing your own, I'd recommend a NSC DP8473--it has the benefit
of full FM and MFM support, including reading and writing 128 byte MFM
data.  Not even the NSCPC8477 can do that--and you can forget the Intel
chips like the 82077/78 for FM.

--Chuck