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.

6 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.

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