difference between LSI-11 CPU's M7264 and M7270

Gooijen, Henk GOOI at oce.nl
Mon Sep 26 10:29:38 CDT 2005


> >Together with the info from Pete I am on the safe side to 
> >turn on power.
> >BTW, I assume that you made a typo in the serpentine:
> >>  option2|option1
> >>  option3|option4
> >>  option5|option6
> >That last line should be option6|option5, or ......?
> >
> 
> As shown it is correct.  2,3,5 on the left: 1,4,6 on the right.
> it's one of the odder -11 backplanes.  I believe the reson 
> for that odd layout is when cascading multiple boxes (BA11M) 
> the cables orient easier as option 5 to next box topleft is 
> the shown configuration and the REV-11 prom boot is nominally 
> in option6 as bus grant continuity is not required for most memories.
> 
> My source was the Microcomputer handbook 1976/77.
> I also have one with core in it.
> 
> Allison

Allison,
thanks again!  Indeed odd, as that is not the "serpentine rule" !
I am sure that I would have made that mistake ...

73,
- Henk, PA8PDP.




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