Re: HP 82973 revision A Message #2 Posted by Katie on 21 Feb 2004, 10:26 p.m., in response to message #1 by Miki Mihajlovic
Revision A (manual dated March 1984) (and the way the card is marked) uses the dip switches as address lines A8-A15, Revision C (manual dated May 1987) uses the dip switches as address lines A3-A10.
On Revision A boards the 8 least significant address bits (A0-A7) are always zero on Revision C boards the 3 least significant address (A0-A2) bits are always zero as are bits A11-A15.
The Revision A default dip switch settings (1700h) are:
00010111. So the full default address is: |00010111|00000000 = 1700h (note the | marking the start/end of the dip switch). On Revision C boards the default dip switch settings (700h) are: 11100000. So the full address is: 00000|11100000|000 = 0700h.
The confusing point with Revision C boards is that the dip switch does not delineate hex digits as it does with Revision A.
I hope that helps.
-Katie
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