Here are notes I made while researching how to hook up a 2.5" Conner
SCSI disk drive with a 40 pin connector.  The drive in question is a
CP2045.  I couldn't find info on the pinout directly, but using info
gleaned from an Apple Powerbook manual, and looking at the actual
ribbon cable inside the Powerbook I ripped the SCSI drive from, I
think I've figured out the pinout.

From the Macintosh Powerbook 140/170 Developer note, found courtesy of
google.

Table 1-4 Pinouts for internal and external HDI-30 SCSI connectors

Pin number	HDI-30(internal)	HDI-30(external)

1		DISK.+5			/LINK.SEL
2		DISK.+5			/DB0
3		GND			GND
4		GND			/DB1
5		GND			TERMPWR (not used; reserved for
						 future use)
6		/DB0			/DB2
7		/DB1			/DB3
8		/DB2			GND
9		/DB3			/ACK
10		/DB4			GND
11		/DB5			/DB4
12		/DB6			GND
13		/DB7			GND
14		/DBP			/DB5
15		DISK.+5			GND
16		/BSY			/DB6
17		/ATN			GND
18		/ACK			/DB7
19		GND			/DBP
20		/MSG			GND
21		/RST			/REQ
22		/SEL			GND
23		/C/D			/BSY
24		/I/O			GND
25		/REQ			/ATN
26		GND			/C/D
27		GND			/RST
28		GND			/MSG
29		DISK.+5			/SEL
30		DISK.+5			/I/O



Conner 40 pin SCSI pinout, derived from above table for internal
connector, and looking at the flex cable that attaches to the drive.
Pin 17 is the key position on the disk drive connector.

Looking at the 40 pin connector on the Conner 2.5" SCSI drive, it's
numbered like this:
+---------------------------------------------------------------+
|                 HDA                                           |
|              ASSEMBLY                                         |
+---------------------------------------------------------------+
  39 . . . . . . . . . . .   . . . . . . . . 1  7 . . . . 1  
  40 . . . . . . . . . . . . . . . . . . . . 2  8 . . . . 2

Notice the missing pin at position 17.

Here is the pinout of the 40 pin connector:

Disk	HDI-30	 Signal		Disk	HDI-30	 Signal
Drive	internal Name		Drive	internal Name

1	1	 Disk +5	21	NC
2	2	 Disk +5	22	14	 /DBP
3	3	 GND		23	NC
4	4	 GND		24	15	 Disk +5
5	5	 GND		25	17	 /ATN
6	6	 /DB0		26	16	 /BSY
7	NC			27	19	 GND
8	7	 /DB1		28	18	 /ACK
9	NC			29	21	 /RST
10	8	 /DB2		30	20	 /MSG
11	NC			31	NC
12	9	 /DB3		32	22	 /SEL
13	NC			33	24	 /I/O
14	10	 /DB4		34	23	 /C/D
15	NC			35	26	 /GND
16	11	 /DB5		36	25	 /REQ
17	Key			37	27	 GND
18	12	 /DB6		38	28	 GND
19	NC			39	29	 Disk +5
20	13	 /DB7		40	30	 Disk +5



The smaller 8 pin connector is for setting the SCSI ID, and
disabling parity, I think.  I found the following information
in the SCSI-faq dated 12/8/94, located by google here:

  http://jedi.ks.uiuc.edu/~johns/links/comp/SCSI-Faq.txt

  Table A                       
  ID   E-1  E-2  E-3
  0    out  out  out
  1    in   out  out
  2    out  in   out
  3    in   in   out
  4    out  out  in
  5    in   out  in
  6    out  in   in
  7    in   in   in

  Jumper E-4 to disable parity.

I think that means E1 is pins 1&2, E2 is pins 3&4, etc.



Note that I have not yet actually used this info to hook up a drive.
I just wrote up what I gleaned from a my web research.  Someday I hope
to hook up a small 2.5" SCSI drive to my old Atari 8-bit computer.
Yet another project...