Mouse traps in A13 reference schematic


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Yesterday we discovered that the reference A13 schematic we got have some mouse traps inside.

The DDR3 RAM ball assignments are shifted with +1, this means if A0 address signal is assigned as K3 on Hynix datasheet it’s labeled K4 on A13 “reference” design schematic.

I still don’t know if this is intentional or not.

As explained on this tread http://lists.phcomp.co.uk/pipermail/arm-netbook/2012-March/002881.html the factories in China which produce electronic devices have no or little R&D, they rely on the SoC manufacturer to provide them with chips, schematics, reference PCB layout and everything they need just to start production, so they just pay for the design to “solution companies” and do what they can best – assembly cheap devices.

There may be other traps as well, but this will not stop us to complete our schematic, my great worries now are if the processor pin assignments are correct in the A13 datasheet :) as we have nothing to compare with.

I already ordered one A13 tablet from China as these are still not available on ebay, so we will be able to do some reverse engineering and track if all ports on the A13 are defined correctly but this will delay a bit the project.

Hopefully I will got the A13 tablet next week and will tear it on parts, then post my findings here :)

I already wrote note in the GitHub A13-PDF readme.txt about this problem with the schematic so other people who watch this project beware.

2 Comments (+add yours?)

  1. 0xFF
    May 19, 2012 @ 00:37:46

    Where could we get the same tablet as you ?

    Reply

    • OLIMEX Ltd
      May 19, 2012 @ 09:28:20

      this is difficult right now as the A13 tables are in production since 1-2 weeks and the international traders have no stock. I searched on ebay and there was none, then searched some Chinese online sale sites and the info on them is quite confusing, seems A13 now is marketing slogan and you can see hundreds of tablets advertised to have A13 but with pictures and descriptions of A10 tablets. On one such ad was written “A13 tablet with 1.5Ghz Cortex-A8 and HDMI” I sent message to the seller – why do you write 1.5Ghz and HDMI when A13 have no these, and the reply was “You are right!”, so you have to be very cautious with the sellers, they will sell you A10 tablet advertised as A13, this is why I contacted friend of mine who is in China and explained to him what I need, today he send me one http://www.onda.cn/Mp3/ProductInfo.aspx?ProductId=189 and it should be by me in Monday for hacking :)

      Reply

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