board scan, design reconstruction (was IMSAI)

[Dave McGuire]

On Mar 1, 2008, at 10:39 AM, dwight elvey wrote:
>> How about a PCI floppy controller board? Maybe with some supplementary
>> logic to allow raw track reads? Possibly a BIOS to boot from? An 
>> external
>> floppy drive connector?
>>
>> Just wondering how complicated such a thing would be. Thanks!
>
>  It would be relatively easy if you did most of the work in a DSP chip.
> For the floppy end, you need a parallel port to read status and
> write controls.
>  For reading raw data, a 7474 flipflop, an adjustable clock
> and a DSP chip, such as a ADSP2118 or similar.
>  Then you'd need a bus interface to the PCI bus.

   Why not just build that bus interface and put a floppy controller 
chip (WD2797, 765, etc) on the other side of it?  I suppose the DSP 
chip would give you much greater flexibility in terms of being able to 
download new code into it to support different formats (even different 
types of modulation), but it's much more complex.

   Hmm.  Now that I think about it, a DSP-based floppy controller would 
be amazingly flexible.  Wow..

            -Dave

--
Dave McGuire
Port Charlotte, FL