ROM SIMM Pinout
This page shall contain ROM SIMM Pinouts.
Motorola 680×0 64-Pin ROM SIMM
This pinout applies to the Macintosh IIfx, IIci, IIsi and SE/30. If you have a different 680×0 Mac with a 64-pin SIMM slot, it is likely to use this pinout as well. If you use this pinout to construct an actual ROM SIMM, please take note that address bits should be offset by 2. For example, on your ROM chips, A0 should be connected to A2 in this pinout. A1 goes to A3, etc. This is because the ROM SIMM puts out 32-bits of data for each address, whereas each actual address is 8 bits of data. Skipping the first two bits effectively divides the address by 4. Forum member trag (Jeff Walther) has provided this information:
According to TGTTMFH:
ROM SIMM Socket
Pin Number Signal Name 1 +5V 2 A0 3 A1 4 A2 5 A3 6 A4 7 A5 8 A6 9 A7 10 GND 11 ROM CS_ 12 ROM OE_ 13 +5 14 D0 15 D1 16 D2 17 D3 18 D4 19 D5 20 D6 21 D7 22 D8 23 D9 24 D10 25 D11 26 D12 27 D13 28 D14 29 D15 30 GND 31 A8 32 A9 33 A10 34 A11 35 A12 36 A13 37 A14 38 A15 39 A16 40 A17 41 A18 42 A19 43 A20 44 A21 45 A22 46 +5V 47 D16 48 D17 49 D18 50 D19 51 D20 52 D21 53 D22 54 D23 55 D24 56 D25 57 D26 58 D27 59 D28 60 D29 61 D30 62 D31 63 +5V 64 GND
PowerPC 160-Pin ROM SIMM
This is the pinout for Apple's (mostly) universal firmware module. As far as I can tell it was used from the NuBus Powermacs through the Beige G3 in their main professional machines. The consumer (LC/Performa) machines had other arrangements.
Disclaimer: I'm not responsible if you use this information to damage something or otherwise screw up. I might have made mistakes typing this. I might be insane. This pinout seemed to work for me. Keep in mind the effect hours with a multimeter, a couple of firmware modules and some ROM datasheets is likely to have had on my mental stability.
Power Surge (PS) is the generic name for the 7500, 8500, 9500 and clones and later family models. The 7200 uses the same ROM (yes, and the same code) and the same firmware module as the PS.
The Apple Network Server uses the same type of Firmware module as the Power Surge, though with different contents in the chips, of course. The prototypes of the PEX (PM9700) also use this ROM module, with still different code on the chips.
The voltage supply pins of the Beige G3 are different from the earlier modules because the Beige G3 uses a 3.3V supply and the earlier machines use a 5V supply. As far as I know the Beige G3 is the only machine that uses the 3.3V supply configuration. All the other machines, including the PEX using the 5V supply configuration.
The pins of Apple's universal firmware module are numbered 1 through 160. There are 80 on each side. Usually modules will have some numbers silk screened on them to help you out. The module is a DIMM. Every pin is unique. Pins on opposite sides of the board are not connected the way they are on SIMMs.
From edge to notch to notch to edge, they go 1 - 30, 31 - 55, 56 - 80, flip sides, 81 - 110, 111 - 135 and 136 - 160.
The first column in the list below is the Beige pin. The second column is the Power Surge (PS) pin. I have not explicitly mapped out all the pins on the NuBus Mac ROM module, but I would expect the pinout to be very similar if not identical to the Power Surge pinout. I have confirmed that it follows the same basic pattern.
The firmware module is 64 bits wide. On early machines this is usually achieved with four 16 bit wide storage chips, although larger numbers of narrower chips were sometimes used. On the Beige G3 there are just two 32 bit wide ROM chips. No one makes anything like that anymore (32 bit wide non-volatile memory chips).
The HL, HH, LL and LH designations on the Power Surge data pins refer to which ROM chip those data pins connect to. So, for example, you'll find four ROM chips on the motherboard labeled with those four designators. The D0 HL pin in the ROM socket connects to the D0 pin on the HL ROM chip which is soldered to the motherboard. In the X500 series, chip 341S0171 = LL, 341S0170 = LH, 341S0169 = HL and 341S0168 = HH. In the Kansas: 341S0380 = HH, 341S0381 = HL, 341S0382 = LH, 341S0383 = LL.
On the original G3 ROM (revision A) 341S0402 = H and 341S0403 = L.
There is no ROM soldered to the motherboard, but the Beige G3 uses two 32 bit wide ROM chips. The L and H refer to the high and low ROM chips.
More notes at the bottom.
Pin Beige PS 1 NC Vcc 2 GND GND 3 Vpp? Vpp? (this would be used on a programmable module with old EEPROMs) 4 D16 L D0 HL 5 D17 L D1 HL 6 D18 L D2 HL 7 D19 L D3 HL 8 Vcc N/A 9 NC Vcc 10 Vcc NC 11 D20 L D4 HL 12 D21 L D5 HL 13 D22 L D6 HL 14 D23 L D7 HL 15 GND GND 16 D24 L D8 HL 17 D25 L D9 HL 18 D26 L D10 HL 19 D27 L D11 HL 20 Vcc NC 21 NC Vcc 22 NC? NC 23 D28 L D12 HL 24 D29 L D13 HL 25 D30 L D14 HL 26 D31 L D15 HL 27 GND GND 28 NC? NC 29 NC? NC 30 A2 A2 31 A4 A4 32 A6 A6 33 A8 A8 34 A10 A10 35 NC NC 36 NC NC 37 WE WE (For programmable modules, also may connect to pin 117) 38 OE H OE A1L (May also connect to pin 118) 39 NC NC 40 Vcc NC 41 NC Vcc 42 NC NC 43 GND GND 44 A12 A12 45 A14 A14 46 A16 A16 47 A18 A18 48 NC NC 49 NC NC 50 NC NC 51 NC NC 52 NC NC 53 GND GND 54 D16 H D0 HH 55 D17 H D1 HH 56 D18 H D2 HH 57 D19 H D3 HH 58 GND GND 59 NC Vcc 60 NC NC 61 D20 H D4 HH 62 D21 H D5 HH 63 D22 H D6 HH 64 D23 H D7 HH 65 GND GND 66 D24 H D8 HH 67 D25 H D9 HH 68 D26 H D10 HH 69 D27 H D11 HH 70 Vcc NC 71 NC Vcc 72 NC NC 73 D28 H D12 HH 74 D29 H D13 HH 75 D30 H D14 HH 76 D31 H D15 HH 77 GND GND 78 NC NC 79 Vcc NC 80 NC Vcc 81 NC Vcc 82 GND GND 83 NC NC (May be Vpp on programmable modules) 84 D0 L D0 LL 85 D1 L D1 LL 86 D2 L D2 LL 87 D3 L D3 LL 88 Vcc NC 89 NC Vcc 90 Vcc NC 91 D4 L D4 LL 92 D5 L D5 LL 93 D6 L D6 LL 94 D7 L D7 LL 95 GND GND 96 D8 L D8 LL 97 D9 L D9 LL 98 D10 L D10 LL 99 D11 L D11 LL 100 Vcc NC 101 NC Vcc 102 NC NC 103 D12 L D12 LL 104 D13 L D13 LL 105 D14 L D14 LL 106 D15 L D15 LL 107 GND GND 108 A0 A0 109 A1 A1 110 NC NC 111 A3 A3 112 A5 A5 113 A7 A7 114 A9 A9 115 _CE _CE 116 Vcc 1Kohm to GND? 117 NC OR WE for back of module on programmable modules, may also connect to 37 118 _OE L _OE all, also connects to 38 119 NC NC 120 Vcc NC 121 NC Vcc 122 NC NC 123 GND GND 124 A11 A11 125 A13 A13 126 A15 A15 127 A17 A17 128 NC NC 129 NC NC 130 NC NC 131 NC NC 132 NC NC 133 GND GND 134 D0 H D0 LH 135 D1 H D1 LH 136 D2 H D2 LH 137 D3 H D3 LH 138 Vcc NC 139 NC Vcc 140 NC NC 141 D4 H D4 LH 142 D5 H D5 LH 143 D6 H D6 LH 144 D7 H D7 LH 145 GND GND 146 D8 H D8 LH 147 D9 H D9 LH 148 D10 H D10 LH 149 D11 H D11 LH 150 Vcc NC 151 NC Vcc 152 NC NC 153 D12 H D12 LH 154 D13 H D13 LH 155 D14 H D14 LH 156 D15 H D15 LH 157 GND GND 158 NC NC 159 Vcc NC 160 NC Vcc
1) CE (pin 115) can simply be tied low or not. 2) OE low (pin 118) and OE high (pin 38) do not need to be connected together on the firmware module--they're connected on the motherboard. 3) Pin 116 connects to the CE_ of the motherboard ROM on PS and 7200 machines. If you tie it high, it disables the motherboard ROM so that the module ROM/firmware can take over. 4) While pin 122 may be grounded on some Beige modules, connecting it to ground seems to disable support for more than 512 MB of RAM in the Beige. 5) The Beige will not work with 120 ns flash. 90 ns or faster is needed, although I haven't tested 100 ns. 6) The PowerSurge seems to work with 120 ns flash, but stick to 90 ns or better to be safe.