Doggone limit on message length! This is the third time I'm posting this, only this time without the quoted stuff.
I've come to the conclusion (based on all reports) that a "standard" 3.3v EDO SODIMM will _NOT_ work in a 2400 without some modification. Whether that mod is trivial, and therefore actually _do-able_, or not is the question now. I'm not sure, but what it looks like to me is that perhaps a pair of address lines need to be swapped on a standard sodimm to allow use in a 2400. Possibly. Maybe. : >) ". . . the connections to device address bits 9 and 10 must be swapped on the DIMM." What that exactly means, heck if I know. Swapped compared to . . . ? A "standard JEDEC SO-DIMM" _may_(?) just describe the mechanical spec and not the electrical spec. As I have no idea what a "standard" 3.3v EDO SODIMM's electrical specs are, anyone out there knowledgable enough to compare that with the 2400's requirements? (see below) Dan K (ignernt az dawg spyt n prowd uv it!) ------------------------------------------------------------------------ >From the "Delta Guide to the PowerBook 2400c Computer" devnote <http://developer.apple.com/techpubs/hardware/Developer_Notes/Macintosh_CPU s-PPC_Portable/PowerBook_2400c.pdf> RAM Expansion The PowerBook 2400c computer accommodates one SO (small outline) DIMM for RAM expansion. The DIMM can have either 16 or 32 MB of additional RAM. The mechanical characteristics of the RAM expansion DIMM are given in the JEDEC speci�cation for the 144-pin 8-byte DRAM SO DIMM. The PowerBook 2400c computer can accommodate an SO DIMM with a height of 1.0, 1.25, or 1.5 inches. While the JEDEC speci�cation for the SO DIMM de�nes a Serial Presence Detect (SPD) feature that contains the attributes of the module, the Macintosh PowerBook 2400c computer does not support the SPD feature. The computer requires the DIMM to contain EDO DRAM devices with access times of 60 ns or less. The electrical characteristics of the DIMM must be the same as those of the RAM expansion module for the PowerBook 3400 computer, as described in the PowerBook 3400 Developer Note. To obtain that developer note, please refer to �Supplemental Reference Documents� on page vii. IMPORTANT - Unlike the RAM expansion module for the PowerBook 3400 computer, the SO DIMM for the PowerBook 2400c computer does not require an address buffer. The PowerBook 2400c computer can accept a DIMM that uses 64-megabit DRAM devices. The electrical characteristics of such a DIMM must be the same as those of the corresponding expansion module for the PowerBook 3400 computer: the DRAM devices must be 4 M by 16-bit devices with 12-by-10 address multiplexing, and the connections to device address bits 9 and 10 must be swapped on the DIMM. ------------------------------------------------------------------------ >From the "Macintosh PowerBook 3400 Computer" devnote <http://developer.apple.com/techpubs/hardware/Developer_Notes/Macintosh_CPU s-PPC_Portable/PowerBook_3400.pdf> Table 4-13 {lists the types of DRAM devices possible, along with the pin assignments} Type of DRAM device 512K by 8; 10 row bits, 9 column bits 2M by 8; 12 row bits, 9 column bits 1M by 4 or 1M by 16; 10 row bits, 10 column bits 2M by 8; 11 row bits, 10 column bits 4M by 1 or 4M by 4; 11 row bits, 11 column bits 4 M by 16; 12 row bits, 10 column bits RAM Banks The RAM expansion card can have up to four banks of RAM. Banks can be 4 MB, 8 MB, 16 MB, or 32 MB in size. DRAM Device Requirements The DRAM devices used in a RAM expansion card must meet the following minimum speci�cations: * Power supply voltage: 3.3 V * Access type: EDO * Access time: 60 ns or shorter access time * Refresh: CBR, extended refresh capable (L-type) * Refresh cycle: 15.6 ms RAM Expansion Card Electrical Limits The RAM expansion card must not exceed the following maximum current limits on the +3 V supply: * Active 500 mA * Standby 24 mA * Sleep 12 mA During system sleep at the 15.6 �s refresh rate, the current for the entire RAM card must not exceed 12 mA. Vendors of cards that exceed the refresh-current restriction will be required to state in their user manuals that their cards may reduce the amount of time the computer can remain in sleep mode before running down the battery. The capacitive loading on the signal lines must not exceed the following limits: * DATA(0�63): 50 pF * RADDR(0�11): 140 pF * /RAMWE: 140 pF * RAMOE: 140 pF * /RAS(n): 80 pF * /CAS(n): 50 pF ---------- Duo/2400 List, The friendliest place on the Net! A listserv for users and fans of Mac subportables. FAQ at <http://www.themacintoshguy.com/lists/DuoListFAQ.shtml> Be sure to visit Mac2400! <http://www.sineware.com/mac2400> To unsubscribe, E-mail to: <[EMAIL PROTECTED]> To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]> Need help from a real person? Try. <[EMAIL PROTECTED]> ---------- Dr. Bott | 10/100 Ethernet for your 2400 is finally here! MPC-100 | <http://www.drbott.com/prod/mpc100.html> RoadTools $30 PodiumPad available at Apple retail stores, $20 Traveler CoolPad at Staples. Both in white for iBooks at <http://roadtools.com> Midwest Mac Parts ][ <http://www.midwestmac.com> After-market parts for Macs. ][ 888-356-1104 ][ MacResQ Specials: LaCie SCSI CDR From $99! PowerBook 3400/200 Only $879! Norton AntiVirus 6 Only $19! We Stock PARTS! <http://www.macresq.com>
