WD 1793 FDCs for sale - test-drb@ccmp.vtda.org

30 Aug 2005

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Subject: Re: WD 1793 FDCs for sale
   From: Jeff Walther <trag at io.com>
   Date: Fri, 26 Aug 2005 02:17:18 -0500
     To: cctech at classiccmp.org

 Date: Tue, 23 Aug 2005 00:18:14 +0100
From: Philip Pemberton <philpem at dsl.pipex.com> 
 Speaking of the 765s, I still need to build an MFM
data separator... 
Is there any reason not to just track down some WD92C32 or WD92C16? 
I think SMSC (FDC prefix) sold some similar chips too. 
The construction of a dtat sep is fairly easy and there was a design on
the net someone else posted thats right from the Apnotes.  
It's a 7474/74174/and 32x8 fuse rom(needs to be faster than 50NS)

...
 I did see a nice lot of WD92C16s on Ebay a year or two
ago.  I think 
that will work as long as you need to read 1.44MB floppies.  But I 
haven't seen any more of them since then. 
The 9216 is a versatile data sep.  It will do ALL data rates. All you 
have to do is provide the correct clock for the rate(s).

Another though scarce is the 9229, thats the 9216+ write precomp hardware.
It also works for all rates. The 9239 is an enhanced version.

SMSc chips in oder by appearance:
Data seps 9216, 9236
Data sep and clock generator (with srite precomp logic) 9229, 9238, 9239, 9249

Those with "C" in the middle are Cmos version of the Nmos/Hmos originals.

Allison