SE/30 PDS Slot
PDS slot of Macintosh SE/30

Information about pin-assignments of the SER/30 PDS slot may be useful, particularly when you try to modify your SE/30.
The PDS slot of Macintosh SE/30 is made of a 120-pin EuroDIN connector.
The pin-assignments, signal-assignments, and meaning of the signals are shown in the figure and tables below.

Reference:
Guide to the Macintosh Family Hardware, 2nd Ed., Addison Wesley, 1990.

Pin Assignments of the PDS Slot

Numbers 1, 40, 81 and 120 are printed on the logic board for right positioning.

Signal Assignments of the PDS Slot

A B C
1 Reserved Reserved PWROFF
2 Reserved GND /NUBUS
3 /BUSLOCK /TM1A /TM0A
4 /IRQ3 /IRQ2 /IRQ1
5 /IPL2 /IPL1 /IPL0
6 /CIOUT /DS /RMC
7 /STERM /CBACK /CBREQ
8 /DSACK1 /DSACK0 R/W
9 SIZ1 SIZ0 /AS
10 /BGACK /BG /BR
11 FC2 FC1 FC0
12 /RESET /BERR /HALT
13 D0 +5V D1
14 D2 D3 D4
15 D5 D6 D7
16 D8 GND D9
17 D10 D11 D12
18 D13 D14 D15
19 D16 +5V D17
20 D18 D19 D20
21 D21 D22 D23
22 D24 GND D25
23 D26 D27 D28
24 D29 D30 D31
25 A31 +5V A30
26 A29 A28 A27
27 A26 A25 A24
28 A23 GND A22
29 A21 A20 A19
30 A18 A17 A16
31 A15 +5V A14
32 A13 A12 A11
33 A10 A9 A8
34 A7 GND A6
35 A5 A4 A3
36 A2 A1 A0
37 +5V +5V +5V
38 CPUCLOCK ECLK C16M
39 GND GND GND
40 -12V -5V +12V

Numbers from 1 to 120 are actually assigned to the PDS slot (EuroDIN connector) pin positions on the logic board circuit.
Four positioning numbers 1, 40, 81 and 120 are printed on the component side of the logic board.
On the rear side of the logic board, mesh patterns indicates the ground (GND) lines.
By comparing the GND pins (B2, B16, B22, B28, B34, A39, B39, C39) with the mesh patterns, we can determine the correspondence between the actual pin positions/numbers (1-120) and the assignment numbers (A1-A40, B1-40, C1-C40) in the above figure.

Explanation of PDS signals

A (31-0) Address lines.
FC (2-0) Function code.
D (31-0) Data lines.
/IPL (2-1) Interrupt priority lines.
/CIOUT Cache inhibit out.
/CBREQ Cache burst request.
/CBACK Cache burst acknowledge.
/STERM Synchronous termination.
/DSACK (1-0) Data acknowledge.
/SIZ (1-0) Transfer size.
/BR Bus request.
/BG Bus grant.
/BGACK Bus grant acknowledge.
/RESET System reset.
/BERR Bus error.
/RMC Read modify cycle.
R/W Read/write.
/AS Address strobe.
/HALT Halt.
/DS Data strobe.
PWROFF Power off.
/NUBUS NuBus space access.
/BUSLOCK NuBus buslock.
/TM1A NuBus transfer mode bit 1.
/TM0A NuBus transfer mode bit 0.
/IRQ (3-1) Interrupt input.
CPUCLOCK 16.67MHz CPU Clock.
ECLK E clock.
C16M 15.6672MHz gen clock.
GND Ground.