[Coco] HD floppy controller update: success!

[jdaggett at gate.net]

Joel

If cost  is an issue believe me y ou don't want to go off and buy one or two boards from a 
fab house. Unless  yo uare interested in buying them for about $50 a board. 

Better solution is to have Chuck buy a given quantity of boards and buy a single board off  
him. Two layer boards the size of the small disk controller card with routing, soldermask and 
silkscreen will be about $15 per board at 20 board order. 

james


On 5 Jul 2008 at 11:35, Joel Ewy wrote:

> Hey Chuck,  this is good stuff you're working on.
> 
> IMHO, I think a High Density CoCo OS-9 disk should be formatted the
> same as an MM/1 HD floppy.  The MM/1 uses the WD37C65, and 33 256-byte
> sectors per track.  I don't have any info immediately at hand about
> gap length.  In the MM/1 technical manual the "rates" parameter to
> dmode is $10.  Perhaps this is passed directly to the FDC, and the
> 37C65 datasheet might give more specific info.
> 
> If you do decide to manufacture some boards, my temptation level would
> go sky high.  Cost would be a factor for me.  PCB only option would be
> cool.  But I may have to download Eagle and see if I can fab a
> double-sided board.  I have a homebrew CNC drill that I've done far
> too little with so far.  I wonder where I can get ahold of the
> 82077AA.
> 
> Nice work!
> 
> JCE
> 
> Chuck Youse wrote:
> > So after working pretty much dawn till dusk yesterday, and a couple
> > more hours this morning, I've proven that the CoCo 3 at 1.78MHz can
> > indeed read high-density floppies with the 82077AA-1!  No HALT
> > required!  I've successfully read sectors from all parts of a
> > PC-formatted disk (and verified the data).
> >
> > Of course, for the Coco 256-byte sectors are MUCH preferred; ideally
> > 36 256-byte sectors per track.  Has anyone ever heard of such a
> > format?  I could use some gap length hints.  Also, does anyone know
> > how I might format such a disk under Linux?  setfdprm/fdformat
> > doesn't seem to do the trick (fdformat ignores the setfdprm
> > parameters... dumb)
> >
> > C.
> >
> >
> >
> >
> >
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> >
> >   
> 
> 
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