# 72 pin SIMM

SIMM=Single Inline Memory Module

(at the computer)

72 PIN SIMM at the computer.

Pin | Non-Parity | Parity | Description
--- | --- | --- | ---
1 | VSS | VSS | Ground
2 | DQ0 | DQ0 | Data 0
3 | DQ16 | DQ16 | Data 16
4 | DQ1 | DQ1 | Data 1
5 | DQ17 | DQ17 | Data 17
6 | DQ2 | DQ2 | Data 2
7 | DQ18 | DQ18 | Data 18
8 | DQ3 | DQ3 | Data 3
9 | DQ19 | DQ19 | Data 19
10 | VCC | VCC | +5 VDC
11 | n/c | n/c | Not connected
12 | A0 | A0 | Address 0
13 | A1 | A1 | Address 1
14 | A2 | A2 | Address 2
15 | A3 | A3 | Address 3
16 | A4 | A4 | Address 4
17 | A5 | A5 | Address 5
18 | A6 | A6 | Address 6
19 | A10 | A10 | Address 10
20 | DQ4 | DQ4 | Data 4
21 | DQ20 | DQ20 | Data 20
22 | DQ5 | DQ5 | Data 5
23 | DQ21 | DQ21 | Data 21
24 | DQ6 | DQ6 | Data 6
25 | DQ22 | DQ22 | Data 22
26 | DQ7 | DQ7 | Data 7
27 | DQ23 | DQ23 | Data 23
28 | A7 | A7 | Address 7
29 | A11 | A11 | Address 11
30 | VCC | VCC | +5 VDC
31 | A8 | A8 | Address 8
32 | A9 | A9 | Address 9
33 | /RAS3 | /RAS3 | Row Address Strobe 3
34 | /RAS2 | /RAS2 | Row Address Strobe 2
35 | n/c | PQ3 | Parity bit 3 (for the 3rd byte, bits 16-23)
36 | n/c | PQ1 | Parity bit 1 (for the 1st byte, bits 0-7)
37 | n/c | PQ2 | Parity bit 2 (for the 2nd byte, bits 8-15)
38 | n/c | PQ4 | Parity bit 4 (for the 4th byte, bits 24-31)
39 | VSS | VSS | Ground
40 | /CAS0 | /CAS0 | Column Address Strobe 0
41 | /CAS2 | /CAS2 | Column Address Strobe 2
42 | /CAS3 | /CAS3 | Column Address Strobe 3
43 | /CAS1 | /CAS1 | Column Address Strobe 1
44 | /RAS0 | /RAS0 | Row Address Strobe 0
45 | /RAS1 | /RAS1 | Row Address Strobe 1
46 | n/c | n/c | Not connected
47 | /WE | /WE | Read/Write
48 | n/c | n/c | Not connected
49 | DQ8 | DQ8 | Data 8
50 | DQ24 | DQ24 | Data 24
51 | DQ9 | DQ9 | Data 9
52 | DQ25 | DQ25 | Data 25
53 | DQ10 | DQ10 | Data 10
54 | DQ26 | DQ26 | Data 26
55 | DQ11 | DQ11 | Data 11
56 | DQ27 | DQ27 | Data 27
57 | DQ12 | DQ12 | Data 12
58 | DQ28 | DQ28 | Data 28
59 | VCC | VCC | +5 VDC
60 | DQ29 | DQ29 | Data 29
61 | DQ13 | DQ13 | Data 13
62 | DQ30 | DQ30 | Data 30
63 | DQ14 | DQ14 | Data 14
64 | DQ31 | DQ31 | Data 31
65 | DQ16 | DQ16 | Data 16
66 | n/c | n/c | Not connected
67 | PD1 | PD1 | Presence Detect 1
68 | PD2 | PD2 | Presence Detect 2
69 | PD3 | PD3 | Presence Detect 3
70 | PD4 | PD4 | Presence Detect 4
71 | n/c | n/c | Not connected
72 | VSS | VSS | Ground

## Size:

PD2 | PD1 | Size
--- | --- | ---
GND | GND | 4 or 64 MB
GND | NC | 2 or 32 MB
NC | GND | 1 or 16 MB
NC | NC | 8 MB

## Accesstime:

PD4 | PD3 | Accesstime
--- | --- | ---
GND | GND | 50, 100 ns
GND | NC | 80 ns
NC | GND | 70 ns
NC | NC | 60 ns

Notes: A9 is a N/C on 256k and 512k modules.
A10 is a N/C on 256k, 512k, 1M and 4M modules.
RAS1/RAS3 are N/C on 256k, 1M and 4M modules.

Contributor: Joakim Ögren, Mark Brown, Karsten Wenke, SOYO Computer Inc

Source:
Various productsheets at IBM Memory Products

Copyright © The Hardware Book Team 1996-2001.
May be copied and redistributed, partially or in whole, as appropriate.
Document last modified: 2001-06-07