ewsgroups: sci.electronics Subject: Re: SIMM RAM Pinouts From some previous responses to similar requests: Newsgroups: sci.electronics Subject: Re: Anybody knows simm pin functions?! 30 Pin SIMMs: 30 Vcc 29 Din9 28 /CAS9 27 /RAS 26 Dout9 25 IO8 24 NC 23 IO7 22 GND 21 /WE 20 IO6 19 NC 18 A9 17 A8 16 IO5 15 A7 14 A6 13 IO4 12 A5 11 A4 10 IO3 9 GND 8 A3 7 A2 6 IO2 5 A1 4 A0 3 IO1 2 /CAS 1 Vcc Newsgroups: sci.electronics Subject: Re:72 pin SIMM pinouts: here it is! Here it goes (from the MICRON 1994 DRAM DATA BOOK, p3-197): Pin-# Signal 1 Vss 2 DQ1 3 DQ19 4 DQ2 5 DQ20 6 DQ3 7 DQ21 8 DQ4 9 DQ22 10 Vcc 11 NC 12 A0 13 A1 14 A2 15 A3 16 A4 17 A5 18 A6 19 A10 20 DQ5 21 DQ23 22 DQ6 23 DQ24 24 DQ7 25 DQ25 26 DQ8 27 DQ26 28 A7 29 NC 30 Vcc 31 A8 32 A9 33 /RAS3 34 /RAS2 35 DQ27 36 DQ9 37 DQ18 38 DQ36 39 Vss 40 /CAS0 41 /CAS2 42 /CAS3 43 /CAS1 44 /RAS0 45 /RAS1 46 NC 47 /WE 48 NC 49 DQ10 50 DQ28 51 DQ11 52 DQ29 53 DQ12 54 DQ30 55 DQ13 56 DQ31 57 DQ14 58 DQ32 59 Vcc 60 DQ33 61 DQ15 62 DQ34 63 DQ16 64 DQ25 65 DQ17 66 NC 67 PRD1 68 PRD2 69 PRD3 70 PRD4 71 NC 72 Vss The PRD pins are either open or shorted to Vss (GND) and code the module´s size and access time. BUT: every manufacturer seems to have his own code! As you see there are some NCs - so there is room for future expansion. Hope that helps.