PSP Go screen in PHAT mode

Discussion in 'PSP - Hacking & Homebrew' started by torquesmackee, Mar 22, 2014.

  1. torquesmackee
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    torquesmackee Newbie

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    Feb 28, 2014
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    Ok, so here's my line of thinking;

    1) the lq043 screen used in the psp phat is a 24 bit RGB TFT display, 480 x 272 resolution, with a 40 pin display cable and four pin backlight. It is made by Sharp, and measures 4.3" diagonal.
    2) the lq038 screen used in the psp go is a 24 bit RGB TFT display, 480 x 272 resolution, with a mezzanine connector. This sockets into a display board, and the flex cable which connects all major components to the logic board plugs into the display pcb (from what I can gather from zooming in on Internet photos) with what appears to be a 39 pin cable end. It is made by Sharp, and measures 3.8" diagonal.

    Now, here's what I wish to accomplish. Basically, I'm in the process of cramming a psp phat with a TA-81 logic board into a form factor for which it was never designed. This being the case, I have some space issues which are exacerbated by the 4.3" screen's size. After much searching, it appears that the psp go lcd is the sole alternative, if one wishes to retain pixel density, but step down the size; all other 24 bit RGB TFT displays I have found are larger than 4.3."

    Now, there is precisely zero technical data extant for the lq038 screen, something which I believe reflects some sort of NDA between Sony and Sharp. So, I have foregone any hopes of finding this data. However, it seems to me that, psp architecture being quite similar across its versions, despite some variations, and lcd displays being typically similar, there ought to be a way to connect the lq038 display to the psp phat logic board.

    This would be accomplished by first connecting the screen to a psp go display board, and then tracing the ribbon trace to their respective owners. In this way, one could hope to discover which pins connect where, and comparing it to the lq043 screen's pinout (of which a wealth of information is available) be able to use a flex ribbon jumper, and perhaps some wiring on a connector end, to route the channels to their appropriate terminus.

    Noble and lofty, sure. Also, I believe, entirely over my head. I am not entirely sure how to determine what channels should be colors, or test channels, etc. Another problem is the integration of the lcd backlight into this supposed 39 pin connection, in lieu of having its own, independent cable. Somehow, the pins it connects to would have to be determined, and jumpers would need to be run from those pins to the backlight connector on the phat logic board. This also has problems, as the pins to which the backlight is traced might also operate other things; things which, if connected and given power, could result in catastrophic failure.

    So, my question is this; how would one go about routing the lq038 screen's connections to the correct places? Also, does anyone know if this has been attempted before? I've spent the better part of two weeks studying chip architecture and tft displays, so I do believe it is possible; just need a nudge in the right direction.

    Thanks in advance guys; let's have some fun ;) !