72 Pin SIMM

TECH

HARDWARE

CISCO

LINUX

72 pin SIMM
SIMM=Single Inline Memory Module
Usually found in Intel 486 and Pentium computers.

Bits		32 bit or 36 bit (32+4 parity)
Speed		60ns to 90ns
Size		256kB to 32MB
Voltage	3.3VDC or 5VDC

Fast Page Mode (FPM) and Extended Data Out (EDO).

Pinout

WARNING! If you use a Multimeter to check the connections on the Presence Detection Pins: Do not touch other pins than thhose or ground! The memory module might get damaged from the testing voltage of your Multimeter.

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 / A12	n/c	Not connected / Address 12*
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	DQ15	DQ15	Data 15
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

Accesstime:

PD4 (70)	PD3 (69)	Accesstime
GND	GND	50, 100 ns
GND	NC	80 ns
NC	GND	70 ns
NC	NC	60 ns

Size:

PD2 (68)	PD1 (67)	Size
GND	GND	4 or 64 MB
GND	NC	2 or 32 MB
NC	GND	1 or 16 MB
NC	NC	8 MB

Pinout Table Valid for ECC and NON-PARITY-Modules
ECC modules have Pin 48 tied to Pin 72 = GND

PD4 (70)	PD3 (69)	PD2 (68)	PD1 (67)	Size	Speed	Notes
NC	NC	NC	NC			Free or Invalid
NC	NC	NC	GND	16 MB	60 nS	Non-Parity
NC	NC	GND	NC	32 MB	60 nS	Non-Parity
NC	NC	GND	GND	4 MB	60 nS	Non-Parity
NC	GND	NC	NC	8 MB 8MB	70 nS 70 nS	Non-Parity IBM ECC FRU 92F0098
NC	GND	NC	GND	1 MB 16 MB 16MB	70 nS 70 nS 70 nS	Non-Parity Non-Parity IBM ECC FRU 96F9100
NC	GND	GND	NC	2 MB 32 MB	70 nS 70 nS	Non-Parity
NC	GND	GND	GND	4 MB	70 nS	Non-Parity
GND	NC	NC	NC	8 MB	80 nS	Non-Parity
GND	NC	NC	GND	1 MB 16 MB	80 nS 80 nS	Non-Parity
GND	NC	GND	NC	2 MB 32 MB	80 nS 80 nS	Non-Parity
GND	NC	GND	GND	4 MB 4MB	80 nS 70 nS	Non-Parity IBM ECC FRU 92F0097
GND	GND	NC	NC	16 MB	70 nS	IBM ECC
GND	GND	NC	GND
GND	GND	GND	NC
GND	GND	GND	GND	8 MB	60 nS	Non-Parity

Pinout Table Valid for IBM PARITY-Modules
Pin 48 = Not Connected

PD4 (70)	PD3 (69)	PD2 (68)	PD1 (67)	Size	Speed	Notes
NC	NC	NC	NC			Free or Invalid
NC	NC	NC	GND	1 MB	120 nS
NC	NC	GND	NC	2 MB	120 nS
NC	NC	GND	GND	2 MB	70 nS
NC	GND	NC	NC	8 MB	70 nS
NC	GND	NC	GND	16 MB	70 nS
NC	GND	GND	NC	2 MB 32 MB	80 nS 70 ns	On older machines IBM P/N 92F7205 or 92G7206
NC	GND	GND	GND	8 MB	80 nS
GND	NC	NC	NC			Reserved (*1)
GND	NC	NC	GND	1 MB	85 nS
GND	NC	GND	NC	2 MB	85 nS
GND	NC	GND	GND	4 MB	70 nS
GND	GND	NC	NC			Reserved (*2)
GND	GND	NC	GND	1 MB	100 nS
GND	GND	GND	NC	2 MB	100 nS
GND	GND	GND	GND	4 MB	80 nS

Notes:

Pin 32 (A9) is a N/C on 256k and 512k modules.
Pin 19 (A10) is a N/C on 256k, 512k, 1M and 4M modules.
Pin 46 is A12 on some 64MB modules, e.g. using Samsung K4F640411C chips.
Pin 45/33 (RAS1/RAS3) are N/C on 256k, 1M and 4M modules.

Sources

HP Printer Memory Notes

shawnbehrens.de - HP Printer Memory Explained

HP Printers of the iii - 5 era tend to need FPO SIMMs (EDO will work in some printers) that are 80ns or faster and with Presence Detect enabled. Sometimes you can solder the correct tabs to ground from the solder pads to simulate this.
The SIMM does NOT need parity but, as a rule of thumb, SIMMs with 9 or 18 chips tend to have parity.