From: steve@europa.esd.sgi.com (Motorin' Flarey Henderson)
Subject: Re: VME-P2 EXPANSION connector on a 4D/35GT
Organization:  Silicon Graphics, Inc.  Mountain View, CA
Date: Tue, 15 Sep 92 22:21:21 GMT


Here's the story with the wierd VME P2 connector in the 4D/35.  Since the 
design called for these custom memory SIMMS (for performance), the little
VME backplane had to be moved about 1/2 inch out, compared to where it sits
on the 4D/20 and 4D/25.  There was no space to put the VME P2 connector
on the backplane, which is where it sits on the 4D/20/25.  It was decided
to route the 64 VME P2 lines over to an external connector on the edge of
the board.  We couldn't use the same 96pin DIN connector because it was too
big and not EMI efficient.  There was also the problem that some people would
try to supply power to their external devices thru some of these 64 lines
(which were routed using 8mil lines!).  We settled on a shielded high density
100 pin AMP connector.  64 of the pins are the VME P2 lines.  The remaining
36 lines contain filtered and fused +5, +12, -12, and GND.  It was hoped that
anyone who wished to use this connector would power their external devices
from this power source, rather than the VME P2 lines.  

For those brave souls who want to attempt to interface to the 100 pin AMP
connector, here is the pinout.  You can get all sorts of neato connectors
and cables from your friendly neighborhood AMP distributor.  Unfortunately,
SGI has never officially come up with gadgets for users, since SGI doesn't
officially support any board that uses the VME P2 connector.


1A -	 GND			    1B -    GND
2A -	+5V			    2B -    +5V
3A -	GND			    3B -    GND
4A -	+5V			    4B -    +5V
5A -	GND			    5B -    GND
6A -	-12V			    6B -    -12V
7A -	GND			    7B -    GND
8A -	-12V			    8B -    -12V
9A -	GND			    9B -    GND
10A -	P2, ROWA, PIN 1		    10B	-   P2,	ROW C, PIN 1
11A -	P2, ROWA, PIN 2		    11B	-   P2,	ROW C, PIN 2
12A -	P2, ROWA, PIN 3		    12B	-   P2,	ROW C, PIN 3
13A -	P2, ROWA, PIN 4		    13B	-   P2,	ROW C, PIN 4
14A -	P2, ROWA, PIN 5		    14B	-   P2,	ROW C, PIN 5
15A -	P2, ROWA, PIN 6		    15B	-   P2,	ROW C, PIN 6
16A -	P2, ROWA, PIN 7		    16B	-   P2,	ROW C, PIN 7
17A -	P2, ROWA, PIN 8		    17B	-   P2,	ROW C, PIN 8
18A -	P2, ROWA, PIN 9		    18B	-   P2,	ROW C, PIN 9
19A -	P2, ROWA, PIN 10	    19B	-   P2,	ROW C, PIN 10
20A -	P2, ROWA, PIN 11	    20B	-   P2,	ROW C, PIN 11
21A -	P2, ROWA, PIN 12	    21B	-   P2,	ROW C, PIN 12
22A -	P2, ROWA, PIN 13	    22B	-   P2,	ROW C, PIN 13
23A -	P2, ROWA, PIN 14	    23B	-   P2,	ROW C, PIN 14
24A -	P2, ROWA, PIN 15	    24B	-   P2,	ROW C, PIN 15
25A -	P2, ROWA, PIN 16	    25B	-   P2,	ROW C, PIN 16
26A -	P2, ROWA, PIN 17	    26B	-   P2,	ROW C, PIN 17
27A -	P2, ROWA, PIN 18	    27B	-   P2,	ROW C, PIN 18
28A -	P2, ROWA, PIN 19	    28B	-   P2,	ROW C, PIN 19
29A -	P2, ROWA, PIN 20	    29B	-   P2,	ROW C, PIN 20
30A -	P2, ROWA, PIN 21	    30B	-   P2,	ROW C, PIN 21
31A -	P2, ROWA, PIN 22	    31B	-   P2,	ROW C, PIN 22
32A -	P2, ROWA, PIN 23	    32B	-   P2,	ROW C, PIN 23
33A -	P2, ROWA, PIN 24	    33B	-   P2,	ROW C, PIN 24
34A -	P2, ROWA, PIN 25	    34B	-   P2,	ROW C, PIN 25
35A -	P2, ROWA, PIN 26	    35B	-   P2,	ROW C, PIN 26
36A -	P2, ROWA, PIN 27	    36B	-   P2,	ROW C, PIN 27
37A -	P2, ROWA, PIN 28	    37B	-   P2,	ROW C, PIN 28
38A -	P2, ROWA, PIN 29	    38B	-   P2,	ROW C, PIN 29
39A -	P2, ROWA, PIN 30	    39B	-   P2,	ROW C, PIN 30
40A -	P2, ROWA, PIN 31	    40B	-   P2,	ROW C, PIN 31
41A -	P2, ROWA, PIN 32	    41B	-   P2,	ROW C, PIN 32
42A -	GND			    42B	-   GND
43A -	+5V			    43B	-   +5V
44A -	+5V			    44B	-   +5V
45A -	GND			    45B	-   GND
46A -	-12V			    46B	-   -12V
47A -	GND			    47B	-   GND
48A -	+12V			    48B	-   +12V
49A -	GND			    49B	-   GND
50A -	+12V			    50B	-   +12V



	   5 4 4 4 4    
	   0 9 8 7 6    5 4 3 2 1
	   A A A A A    A A A A A
	-------------||-------------
	\  * * * * * || * * * * *  /
 	 \ * * * * * || * * * * * /
	  -----------||-----------
	   5 4 4 4 4 
	   0 9 8 7 6    5 4 3 2 1
	   B B B B B    B B B B B 

	AMP 100 pin female connector
		Front View



--
steve valin		steve@sgi.com
		   "SHUT UP, LITTLE MAN"		- peter
Newsgroups: comp.sys.sgi