CPS3 - 64Mbit SIMM Pinout

[yavuzg]

I don't know where/when this information can be applicable (perhaps another 32Mbit SIMM =>? conversion) but I took the time and identified the pinout of a CPS3 64 Mbit SIMM pinout. As you know, all the SIMM modules for CPS3 system has 72 pins and although they seem to be double sided, they are directly connected to their pair on the other side of the PCB, meaning there are NOT individual 144 pins...

For the reference, I took the photo of the SIMM and numbered the flash ICs.

There are 2 x Normal pinout and 2 x reverse pinout Fujitsu flash ICs on a 64 Mbit SIMM module. Again they are MBM29F016-90PFTN (Normal pinout) and MBM29F016-90PFTNR (Reverse pinout)


IC1: Reverse Pinout
IC2: Normal Pinout
IC3: Reverse Pinout
IC4: Normal Pinout

There are no flash ICs or solder locations on the back side of the PCB.

Here is the pinout of the 64 Mbit SIMM PCB:

Pin	Conn.	Note
1	Vcc	Common
2	Vcc	Common
3	D7	IC4 (Normal)
4	D6	IC4 (Normal)
5	D5	IC4 (Normal)
6	D4	IC4 (Normal)
7	D3	IC4 (Normal)
8	D2	IC4 (Normal)
9	D1	IC4 (Normal)
10	D0	IC4 (Normal)
11	GND	Common
12	D7	IC3 (Reverse)
13	D6	IC3 (Reverse)
14	D5	IC3 (Reverse)
15	D4	IC3 (Reverse)
16	D3	IC3 (Reverse)
17	D2	IC3 (Reverse)
18	D1	IC3 (Reverse)
19	D0	IC3 (Reverse)
20	GND	Common
21	D7	IC2 (Normal)
22	D6	IC2 (Normal)
23	D5	IC2 (Normal)
24	D4	IC2 (Normal)
25	D3	IC2 (Normal)
26	D2	IC2 (Normal)
27	D1	IC2 (Normal)
28	D0	IC2 (Normal)
29	GND	Common
30	D7	IC1 (Reverse)
31	D6	IC1 (Reverse)
32	D5	IC1 (Reverse)
33	D4	IC1 (Reverse)
34	D3	IC1 (Reverse)
35	D2	IC1 (Reverse)
36	D1	IC1 (Reverse)
37	D0	IC1 (Reverse)
38	N.C.
39	A20	Common
40	A19	Common
41	A18	Common
42	A17	Common
43	A16	Common
44	A15	Common
45	A14	Common
46	A13	Common
47	A12	Common
48	A11	Common
49	GND	Common
50	A10	Common
51	A9	Common
52	A8	Common
53	A7	Common
54	A6	Common
55	A5	Common
56	A4	Common
57	A3	Common
58	A2	Common
59	A1	Common
60	A0	Common
61	GND	Common
62	/RESET	Common
63	GND	Common
64	N.C.
65	N.C.
66	N.C.
67	/CE	Common
68	GND	Common
69	/WE	IC1, IC2
70	/WE	IC3, IC4
71	/OE	Common
72	N.C.

Although I double checked, there are N.C. (Not connected) pins. If you know some/all of them connected to somewhere please comment. From here, I'll move on to the 32/128Mbit module hoping, may be, with a trick or mod converting one into a 64 Mbit SIMM could be possible. But just for now, they seem to be quite different in nature, especially when you look at the common single /CE (Chip Enable) pin on 64 Mbit SIMM where 32 Mbit SIMM has 4 individual /CE pins. Anyway, I'll try to map that one as well...

 

[Darksoft]

That's an awesome work! Thanks a lot.

I believe that the chips go in pairs, so every read or write is always 16 bits but as the flashes are 8 bit, you read or write always from two.

For that reason, there are two /WE
I would expect though also two /OE or two /CE...

Can't wait to see the pinout for 128Mb, I'm sure I'll get some ideas about how to convert them thanks to you.

 

[Derick2k]

Awesome work, it looks like this might lead to 64MB simms being made?!

 

[yavuzg]

That's an awesome work! Thanks a lot.

I believe that the chips go in pairs, so every read or write is always 16 bits but as the flashes are 8 bit, you read or write always from two.

For that reason, there are two /WE
I would expect though also two /OE or two /CE...

Can't wait to see the pinout for 128Mb, I'm sure I'll get some ideas about how to convert them thanks to you.

Thanks Darksoft, it is a tiny work compared to your efforts. Glad that it might be of use...

I've put the 128 Mbit SIMM pinout on a seperate thread but I must say, the pinouts are wildly different that a "feasible" conversion might not be possible.

Awesome work, it looks like this might lead to 64MB simms being made?!

Hopefully

I believe, again the major problem in reproducing these PCBs would be the requirement to source the "extinct" reverse pinout flash ICs. This is all about "justifying" the time and effort against the demand