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Thread: Serial interface to U-boot?

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  1. #1
    Join Date
    Oct 2010
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    6

    Default Serial interface to U-boot?

    What exactly are the pins/pinout for the onboard debug serial port? What are the levels? I think I read that a simple FTDI USB->3.3V adapter cable would work fine. A photo so that I don't have to turn on my brain would be nice.
    Last edited by notserpe; 10-13-2010 at 05:37 PM.

  2. #2
    Join Date
    May 2010
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    In the land of make believe.
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    Quote Originally Posted by notserpe View Post
    What exactly are the pins/pinout for the onboard debug serial port? What are the levels? I think I read that a simple FTDI USB->3.3V adapter cable would work fine. A photo so that I don't have to turn on my brain would be nice.
    The FTDI adapter/TTL converter works fine. I use a USB powered clone of the nokia CA-42 series cable. Cut off the end and done. Costs about 8 bucks for 5 shipped from amazon.com http://www.amazon.com/CA-42-Cable-No.../dp/B000HCD4RW

    The pinout is not so easy. The 3 pad serial header is not populated, but that doesnt matter. The big issue is there is a spot for a serial level converter that isnt installed, so you have to connect to some .1mm spaced pads. The blank chip is labelled U22.

    In this picture, it is right above the serial port. My screwdriver partly covers it.



    If you want some real fun, you can load turbostation firmware on it to goof off like i did. The QNAP TS-209 firmware worked okay... well... it booted at least... It also shares hardware with the Maxtor Shared Storage II. It cannot be installed permanently, and will undo itself every reboot.

    The 2 right pads, 2 up from the bottom right corner, are the ones you want. They have traces shooting towards the capacitors. The top one is RX, bottom one is TX. Ground is anywhere handy, not the USB shell.



    A full dump of a standard boot can be found in one of my previous posts, here: http://patriotmemory.com/forums/show...98&postcount=1
    Last edited by BadIntentions; 10-15-2010 at 12:21 AM.

  3. #3
    Join Date
    Oct 2010
    Posts
    6

    Default Thanks

    Thanks, just the information I was looking for... I think I'm going to add a header to the
    1/2/3 unpopulated spot and simply wire from one side of the TTL converter to the other f
    or cleanness and simplicity. It does look like tedious work at small pitch but I've done
    SMT work before so it shouldn't be a problem.

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