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72 pin Micron SODIMM (Small Outline DRAM Module) (see also InfernoSODIMM)

The largest known working SODIMM is 32M for a total of 40M (under Inferno only):

Crucial also has a 64M, CarlWorth has one, but Inferno does not boot with it. Crucial has a one time discount on memory products http://www.crucial.com/evguide/ as does TWmemphis

TimRiker adds: Blob is configured to only see 16M. I have a 32M and a 64M sodimm. With the 32M I get :

Memory map:                                            
   0x00400000 @ 0xC0000000 (4 MB)
   0x00400000 @ 0xC8000000 (4 MB)
   0x00400000 @ 0xD0000000 (4 MB)
   0x00400000 @ 0xD8000000 (4 MB)

Which is obviously not correct. With the 64M SODIMM there are no messages from blob at all. Changing blob to handle 11 or 12 rows instead of 10 will get all the onboard and the 32M sodimm visible but the onboard will be 8 banks of 1M which the kernel decompressor can not handle.

The StrongARM 1100 is limited to 4 banks of 16M so 64M is as far as we will be able to go. It would be possible to upgrade the onboard memory to 32M and then add a 32M sodimm and get 64M. It might also be possible to get a 64M sodimm working by disabling the onboard memory. and routing nCS0 to an address pin on the SODIMM (hw mods).

erikm says that his sa1100 lart has 32M on board and 2 64M expansion slots for something like:

Memory map:                                            
   0x00400000 @ 0xC0000000 (16 MB)
   0x00400000 @ 0xC8000000 (16 MB)
   0x00400000 @ 0xD0000000 (64 MB)
   0x00400000 @ 0xD8000000 (64 MB)

for a total of 160M. Don't know how/why this works though.

The board that comes in the machine is a Micron MT4LDT232HG-6 with 4 4LC1M16E5-6 chips. TimRiker can't find that chip referenced, but a 4LC1M16C3 is listed as being 1M x 16 (16M) which is likely the right layout. Data for the following is pulled from:


TimRiker presumes the 16M would be MT2LDT432H but does not have one.

The 32M board is a MT4LDT832HG-6 with 4 4LC4M16R6-5 (64MB 3.3V DRAM, 4Mx16 EDO 4K REF) chips. Crucial lists the SODIMM as 8Meg by 32.

The 64M board does not seem to have a Micron part number. There are 8 4LC8M8C2-5 (64MB 3.3V DRAM, 8Mx8 EDO 4K REF) chips on it. Crucial lists the SODIMM as 16Meg by 32.

The part number is not MT8LDT864HG-5, that's a 144 pin version.

IerK added: I've a Kingston M832001 chip, what should be equal to the "largest known working SODIMM" but blob does not even start when I use this chip. As the chip was new, I asume it works (don't know how to test it).

BTW: It's labled: 32MB, 72-Pin, 8Mx32-Bit, EDO, 3.3v, 60ns, Gold, Small Outline DIMM Module

FPascal (1/23/2001) - While speaking with the Crucial tech support guy about RMA-ing the CT8M32E8T6 SODIMMS (note the "E8" vs "E4" in part number) they sent me, he said that the "E8" in the part numbers signifies 8K refresh rates (aren't refresh rates in seconds?), while the "E4" is for 4K refresh rates. This may explain why the 64Mb SODIMMs don't work. He also said that the "E4" version is much older product and that they are getting hard to find.

TomW (2002.04.03) The DRAM on the boards are organized as 10 rows & 10 columns. When a SODIMM is used, it must be a matching number of rows. For example, DRAM is organized as COLUMNS X ROWS, a 12 Column x 10 ROW (32M) SODIMM can be used by changing the MDCNFG value of blob/memsetup-sa1100.S from "0x0334b21f" to "0x0334b23f".

DRAM is sold as 1K, 2K, 4K, and 8K refresh. What this refers to is the number of COLUMNs that the DRAM has (e.g. 10x10, 11x10, 12x10 or 13x10. note that the number of rows, second number, may be 9,10, or 11, it is the columns that are important). The SODIMMs that could be used in the Tux would be anything LESS THAN 8K refresh. This is how you can be sure that your SODIMM will be compatible, insist on 4K refresh for the 32M modules. Most laptops will use either 8K/4K refresh as the Memory Controllers on those machines are extremely flexible, the ARM controller is not!

When you get the SODIMM, grab a copy of the pinout of the edge connector. Then use an Ohmmeter to buzz out the PRD lines (Pins: 11, 69, 70, and 71. The TUX has no/connects on 66-68). If you find that any of those four pins are tied to ground, remove the short to ground on those pins! The PRD pins are used by laptops to read the size of the memory module. On the Tux, the designers chose not to use the PRD lines and placed address bus signals on those pins. With an address line tied to GND (shorted PRD line), the ARM processor will not boot.

Also see: http://www.TuxScreen.net/wiki/view/32MegRamUpgrade

Coast to Coast Memory, (800)4-MEMORY, has 4K refresh SODIMMs for $29.49 per. Their part number is: LGED32U/032/G3V60. You must insist on 4K refresh for that part, if you don't, you will get 8K refresh which do not work in the Tux.

TimRiker (2002.04.02) Blob discovers memory, it does not use the PD or PRD pins. With TomW's help I covered pin 11 on my 64M sodimm up and blob now finds 24M of ram. Stay tuned for further updates.

Memory map:                                                                                 
  0x00400000 @ 0xc0000000 (4 MB)
  0x00400000 @ 0xc8000000 (4 MB)
  0x00400000 @ 0xd0000000 (4 MB)
  0x00400000 @ 0xd0800000 (4 MB)
  0x00400000 @ 0xd8000000 (4 MB)
  0x00400000 @ 0xd8800000 (4 MB)

KenMcguire (2002.04.02) Found a cheap source of 32M SODIMMs


KenMcguire (2002.07.09) adds: Unfortunately these modules have sold out and are no longer available from this source.

There are several ways to use these in a TuxScreen. First is to just plug it in, if you do this your Tux will not boot at all, because of the PRD lines Tim talks about above. If you tape over pin 71, that will correct the problem. Then your Tux will boot up with 24M. This is because these SODIMMS are 8K refresh, 11 row address bits. Still not bad for $7.00 + shipping. Next you can do a hardware mod and a mod to blob, This will result in 38M. Lastly you can change NR_Banks in linux/include/arm-arm/setup.h to let Linux use 10 banks. This will get you 40M. This is on-going research, and better/cheaper/easier solutions are being sought.

MarcusWolschon Maybe you theye 32MB 72pin SoDimm with 4k-refresh will work too: <br> http://www.memory4all.com/hw_prod/Acer.html but intercontinental s&h is heavy. <br> http://www.memoryx.net/pc7-2845.html 50 USD<br> http://www.msline.de/index.htm?angebote/dell_ram.htm 54 (+4 EUR s&h)<br>

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