64Mb Didj mod

by on Apr.14, 2010, under Didj

I have killed a Didj but upgraded one for science today!

pin pulled up when I removed the old chip, will be very hard to fix…

Second attempt was perfect :)

675-1022-1-ND is the part number from Digikey I used

then after I put everything together I forgot there was  a resister that needed to be changed.

PVD[6] is the blue resistor on the left

PVD[7] is the resistor that needs to be moved

the one with the arrow needs to  be moved to the other location

This sets the capacity of the DDR-SDRAM IC connected to the MCU-Y DDR memory bank.

2 ‘ b 00 : 64Mbit

2 ‘ b 01 : 128Mbit

2 ‘ b 10 : 256Mbit

2 ‘ b 11 : 512Mbit

Once that is set you need to hex edit your Lighting boot to change the kernel command line.

8 Comments for this entry

  • avatar

    Wow thats pretty nice im really tempted to buy one of these now :) Can you feel any difference after upgrading?

  • avatar

    A tip for removing pesky SMT components – cover the area in aluminum foil, and cut out a hole for the part you’re removing. Grab two sides of the chip/part with self-closing tweezers – leave it hanging so that it pulls upward slightly on the chip. Blast the area with a hot air gun, wait… and POP! out goes the chip!

    I’ve used this trick successfully dozens of times and have yet to damage anything. Fixing broken pads is a major pain in the ***.

  • avatar

    Wounldn’t it be possible to upgrade to 512Mb any reason not to? More Power required? or expense?

    • avatar

      The maximum ram that the Didj can handle is 128mb, To do that would require two 8x chips from the 16x chip and a lot of pin swapping.

      In theory you could add another 64mb chip and use one of the Gpio from the buttons for chip select but it might be un-sable

      There just isn’t enough chip select pins :(

  • avatar
    Rich Sias

    So, then we are limited to 64mb SD cards ? Will larger one work and just show 64 as usable ? Or are they useless ?

    • avatar

      The 64 MB limit refers to the DDR memory.
      With the Micro Sd cards I have tested up to 4gb so far with no problems. I believe someone had a 8 gig working.

  • avatar
    Richard Arthur

    Have you ever thought about publishing an ebook or guest authoring on other blogs? I have a blog centered on the same information you discuss and would really like to have you share some stories/information. I know my readers would enjoy your work. If you are even remotely interested, feel free to shoot me an email.

  • avatar
    Liza Elle

    wow..this was cool. i never thought of that article. luckily i google the web and reached here. thanks so much. laptop mousepad is not working

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