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Thread: Connection to back side pins

  1. #1

    Connection to back side pins

    What is the recommended best method to connect to the pins on the back or bottom side that are not through holes?

  2. #2
    Senior Member+ KurtE's Avatar
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    It depends.

    What board? Which pins, what is the rest of the board connected as...

    Can be anything from:
    a) solder a wire to the pad.

    b) POGO pins

    c) Many of the boards you can use an SMT connector. You can see one for the 3.2 with the Sparkfun connector kit: https://www.sparkfun.com/products/13925
    I have used these kits as well for T3.5/6 where I might get 2 of the kits and cut the number of pins down for the SMT connectors... Note: Digikey and others selll them.

    c1) T4 - There is flex cable like connector that works for the SD card pins.


    d) With some boards some of us have played around with making our own castellated adapter boards, where we place holes and the like Or others, that can be purchased:
    Some details up on thread: https://forum.pjrc.com/threads/57122...0-Breakout-Kit

    Some sold on Tindie: https://www.tindie.com/products/logl...on-a-standard/

  3. #3
    Sorry, i'm using the Teensy 3.2. and the pins would be 24-33, 3.3v, A12-A13 and the usb sigs.
    I also saw some posts regarding diptrace 3D files you have made (great work). Do you have diptrace component and pattern files you might share?

    BTW are you the same Kurt that used to be on the BasicMicro Atom forum?

    Thanks for the reply.

  4. #4
    Senior Member PaulStoffregen's Avatar
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    The J-lead headers like in Sparkfun's kit work pretty well for the 14 bottom side pads.

    One trick is to solder that J-lead header first, trying to get it lined up as well as possible in the center of the pads. But it's likely to be off by just a little. You can compensate by putting the other pins into whatever sockets or PCB will receive the Teensy board and then set the Teensy onto them, lining the 14 pins up with the place they mate. If the rest of the pins aren't soldered yet, they can tip or move slightly to fit into the holes on Teensy, where you can solder them after everything is lined up.

    If you solder those 28 outside pins first, getting the 14 pins on the bottom lined up takes an incredible amount of skill or luck.

  5. #5
    Senior Member+ KurtE's Avatar
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    Quote Originally Posted by Fluxanode View Post
    Sorry, i'm using the Teensy 3.2. and the pins would be 24-33, 3.3v, A12-A13 and the usb sigs.
    I also saw some posts regarding diptrace 3D files you have made (great work). Do you have diptrace component and pattern files you might share?

    BTW are you the same Kurt that used to be on the BasicMicro Atom forum?

    Thanks for the reply.
    Yep - Was on BasicMicro, Lynxmotion (now RobotShop), Trossen, ...

    So the Sparkfun kit would work. Likewise the Talldog kit works (https://www.tindie.com/products/logl...ut-revision-d/)

    As I mentioned others have build some castellated boards to be able to solder on to bottom of board to avoid the SMT boards and to move all of the pins to outside pins, such that you can use all of them on a breadboard.

    I may have some of those around here for T3.2, but not sure, did one for T4.1 recently. That I assembled one as a way for me to be able to easily test the 4.1 bottom pins (that are setup for PSRAM and FLASH chips, to be able to use them for IO pins...
    Click image for larger version. 

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