JTAG interface: 20pin to 10pin convertor

Discussion in 'The Projects Forum' started by burntside, Jul 5, 2014.

  1. burntside

    Thread Starter New Member

    Jul 5, 2014
    Hi everyone.
    I have a broken keyboard (piano) that has a firmware issue inside. I'm trying to repair it by reflashing the firmware using a JTAG interface (Ulink 2).
    I'm running into a problem where the connector of my Ulink 2 is a 20pin female connector and the one on the board of my keyboard is a 10pin male connector.

    I would like to know how can I build a conversion to be able to connect the two together and be able to repair it.

    Any idea or suggestion would be really appreciated.

    Thank you very much for your time,

  2. bertus


    Apr 5, 2008
  3. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    Who said the 10 pin is specifically a JTAG? It could just be any proprietary ICSP connector.

    You need to trace the connector pins back to the micro's pins, and just wire something up to suit.

    As long as your programmer can program that micro ICSP then you are good to go.
  4. burntside

    Thread Starter New Member

    Jul 5, 2014
    Thank you for your answers!
    I know it's a JTAG interface as I am following someone else's method in which he uses it as a JTAG interface. Now that it is out of the question, how do I convert the 20pin to the 10pin?
    I don't know much about electronic, but I do like to learn and want to do it by myself.
    Would I need a third party component which would act like a bridge between the two connections? Plug the 20pin in one hand and the 10 pin in the other?
    Can I built the convertor? Direct rewiring from the 20 to the 10?
    Any kind of DIY would be greatly appreciated :)
    What should I be cautious about?

    Thank you again for your fast replies, really appreciated!

    Take it easy,

  5. MrChips


    Oct 2, 2009
    Look at the diagrams in the link provided by Bertus.
    Compare the signals on the 20-pin connector with those on the 10-pin connector.
    You will see that there are six signals with the same names plus VCC and GND.
    The only signal that is missing on the 10-pin connector is TRST. This signal is optional and can be left out.

    Simply hand wire the 10-pins over to the similarly named pins on the 20-pin connector.
    No additional components are required besides the proper mating connectors.
  6. burntside

    Thread Starter New Member

    Jul 5, 2014
    Awesome MrChips! (cool name btw!)
    That's what I was thinking of doing! I'll go to the store and try to find the right connector tomorrow. Is there a specific name for this type of connector? 10-pins aligned connector?

    Thanks for your help!