Re: Blank CMS SCSI Card PCBs

[Nels E Satterlund <Nels.E.Satterlund@intel.com>]

Rich Beaudry wrote:
> 
> david@uow.edu.au (David Wilson) wrote in message news:<3ca81344$1@news.uow.edu.au>...
> 
> > http://www.neiparts.net/atmbnkprnt/ncr.php seems to list NCR 5380 chips
> > at $9.69 each. Does not mention package type (DIP/PLCC etc). If they are the
> > right type it might be worth buying a batch for spares.
> 
> Thanks for the link!  I will follow up with them to determine package
> type, and minimum order quantities...
> 
> >
> > If the PALs are combinational (no feedback) they will be trivial to reverse
> > engineer (they have no flip flops). You just apply each possible input
> > to the 8 input pins and record the values on the 8 output pins. Then you
> > work out the simplest equation to generate each of the 8 outputs from the
> > 8 inputs. Then you find the nearest equivalent (eg PALCE16V8 or GAL16V8)
> > and program it.
> 
> Let me preface this by saying that I am a *total* newbie to
> programmable logic, but the way I understood PALs is that you don't
> necessarily know what is an output, and what is an input.  You may
> know that there's a max of, for example, 8 inputs, but you don't know
> where (what pins) they are....  It may not be impossible to decipher,
> but I didn't think it was that easy ... Otherwise, why have a security
> bit??
> 
> Don't get me wrong, I HOPE it's that easy, but I didn't think it
> was....
> 
> Also, if you are interested in a blank board or two, please email me
> OFF-LIST your address, and they wil be sent to you....
> 
> Rich B.

Rich,

16L8 had 10 in, 2 out and 6 i/o. See
http://homepages.fh-regensburg.de/~grf39054/unterlagen/PAL16LR8.pdf
By following the traces on the board to the next part you might be able
to determine if the I/O were used as an I or an O

Nels

-- 
Nels E Satterlund  I don't speak for the company, specially here
NelsS@Starstream.net <-- Use this address for personal Email
My Lurkers motto: I read much better and faster, than I type.