Re: Rev. C SCSI v2 from GSE-Reactive.com

["Michael J. Mahon" <mjmahon@aol.com>]

Henry wrote:
> Another quick update.
>
> Found out my SCSI HDD is fine.  I fried the terminator.  Now I need to find 
> a 50 pin external terminator.  Luckily I had some term packs I was able to 
> install in the drive.  At least it's working again.

Now *that's* unusual!  How did you manage to fry a terminator (without
simultaneously frying everything else on the chain)?

> My old Rev. C card works but the new one just crashes in to monitor on boot. 
> :-(  Now the fun part - checking all the I/O lines of the CPLD to the 
> schematic.  Would be nice if it was that simple, but I'm not holding my 
> breath.  I knew what the risks were trying to incorporate an incompatible 
> design in a CPLD.  We tried to do what made the most sense to make it work 
> though.  Normally one would start small and remove logic in steps, not try 
> to 'stuff' the entire board in the first shot.  It was worth a try though. 
> The main thing is we learned so much by doing what we did.
>
> We'll waste a little more time with it then call it a day.  We have to many 
> other things to worry about right now and there's not too much more to be 
> learned from this project.  Our efforts could be spent working on other CPLD 
> projects and continue our learning while making progress.  If there are any 
> other results I'll post them here.  There are three boards that could be 
> sent out if anyone want's to take a look at how it's crashing and make some 
> suggestions as to what it may be.  Just email and ask.

The first question has to be:  Did the boot sector get read into memory?
My guess is it didn't, but the boot ROM "thought" that it did and
branched to where it would be.

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
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