Order of the Butterfly
Posts: 301 from 2003/2/24
From: Genesi
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So you are saying that my EFIKA pcb itself, not the components placed on it, is manufactured differently than the pcb's for an EFIKA capable of 512mb RAM. That sounds crazy, and I won't believe that until it is proven!
Read the MPC5200B manual, SDRAM controller section. The pads on the board - I believe - connect 16-bit lines from each module, to the 32-bit controller (this is the standard way to do it on the MPC5200B) and there are two chip selects available for SDRAM..
The way I see it (and I have the schematics), adding 4 modules means connecting 4x 8-bit lines to the 32-bit controller and using the second chip select. The traces simply do not support this configuration. You need to add resistors etc. in places you can't get to and somehow escape a pin that's not escaped in the design.
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No where in any of my messages did I say I was going to try to add memory to my EFIKA without proper documentation on how to do it. Given the fine pitch of the memory chips, I would prefer to just send it out to b-plan, or a third party that has the documentation from b-plan, to have it done, as the soldering is difficult to do without the proper tools.
They won't do it. Not unless you order 1000 boards, anyway.
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Saying it is impossible just because b-plan or genesi does not wish to disclose the information on how it is done is like saying that it is impossible for MorphOS to run on a MacMini
Let's put it this way; it's as impossible for MorphOS to run on a Hewlett Packard HP-28C calculator as it is to MANUALLY modify an Efika to use 512MB.
You may be able to solder on new chips to support more RAM using the top solder pads (after desoldering the old ones) but finding ones with the correct specifications that are verified to work with the MPC5200B, and then hacking the firmware to do it, is beyond most people on this forum. Even then it is not guaranteed to work.
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The EFIKA is capable of using up to 512mb of RAM, as it was designed to do so.
No, it was not. It was designed to take 128MB because 512MB was cost prohibitive. The MPC5200B has been verified to use certain sizes of RAM in certain configurations with certain settings. The official line from bplan is that adding more memory requires a small board rework and sourcing new RAM chips and the minimum order is somewhere between 300 and 1000 (depending on the price per unit you wish to pay). It is not because they don't want you to try, it is because the design cannot support what you want to do to it.
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If a few components need to be replaced to make it work, then the cost to do so would have to be weighed against the benefit it would provide and the other alternatives available
You really don't get it..
You can't, it's as simple as that.
[ Edited by Neko on 2008/12/2 18:56 ]
Matt Sealey, Genesi USA, Inc.
Developer Relations
Product Development Analyst