[sebhc] My H8 Systems

Dwight K. Elvey dwight.elvey at amd.com
Tue Jun 1 12:48:23 CDT 2004

Hi Steven
 I thought I'd disassembled the H17 code a while back but
realized that it was the code for my Poly 8813 that I'd
done this on. I disassembled the H17 and looked at the code
sequence and sure enough, it was the wait for index hole
part of the code.
 The problem had me going for a while. I tried both controller
cards that I had and both did the same thing. I put a scope
on the signals going to the disk drive. A number of them were
not working correctly. I could imagine that both drives and
both controllers had the same problems. I should have been
suspicious of what was the real problem. When I got the
disk drives, ( baught separately from the systems ) I noticed
that there was a terminator installed on both drive ( not
a good idea to over load the outputs ). It took me a while
to realize that some idiot had installed the wrong kind of
terminators. The Siemens drives use the kind that has the
common lead to pin 14 and not the straight through type.
I installed a correct termiantor and now thing are working
fine. I was able to check out my code and find the best sequence
to get it working correctly.

>From: "Steven Parker" <sp11 at hotmail.com>
>Dwight says:
>>The code seems to hange at 035.311
>>This seems to be waiting for some RAM to be updated
>>by an interrupt.
>That's the generic delay routine, watching the TICCNT value.  The step motor 
>routine uses it to pace head motions.   If it's trying to move the head to 
>home and not making it, it would make sense that it spends a lot of time in 
>this routine.
>If you've got more than one drive and none step, perhaps the controller 
>board isn't asserting the step line properly in response to the I/O port 
>On my own status:
>Thanks to Walt, all the power swtiches work now.  :-)  I also replaced the 
>blown cap on the 3rd H8's CPU board and now it comes up .. sortof.  
>Sometimes it comes up and looks normal, other times it seems to come up 
>running in user mode (the pc is displayed, and changing).  Even when it 
>comes up and looks normal something else is odd.  If I try the memory test 
>it crashes with lights out and continuous tone.  I'll have to do some more 
>testing on that one.
>Still haven't done anything yet with the drive that steps one way only.
>- Steven
>Learn to simplify your finances and your life in Streamline Your Life from 
>MSN Money. http://special.msn.com/money/0405streamline.armx
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