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Thread: Pins to bring out on a hypothetical larger Teensy4

  1. #26
    Join Date
    Aug 2019
    southwest USA
    very good idea - could even be extended to two break lines - like maybe dacs closest to cpu and 5v tolerance parts
    out on the end so that if you wanted dacs but didn't need 5v tolerance you use the break line furthest from the cpu
    and if you wanted neither you could use the break line closest to the cpu. i have no idea how practical that might be
    given number of copper layers in the board and layout restrictions.

  2. #27
    Senior Member+ mjs513's Avatar
    Join Date
    Jul 2014
    New York
    Been playing with servos for a couple of projects and I know that this might be a sin but it would be nice if a few of the PWM pins could be 5v tolerant - know they all won't be but a few would be nice.

  3. #28
    Junior Member
    Join Date
    Nov 2019
    Another idea... why not this?:

    Click image for larger version. 

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    I mean... why only 1 row on each side?

    Make it not longer... make it wider :-) Or make it longer + wider + cutable

    Then anyone can place pin headers where they want them.
    And then we never have a pinout problem!

    Be creative!

  4. #29
    Having only one row on each side means you can plug into a breadboard. Two rows you can't.

  5. #30
    Senior Member+ KurtE's Avatar
    Join Date
    Jan 2014
    My $.02

    Allowing the board to be Cut or snapped:

    Having it, such that it can be cut or the like could create lots of other issues. Like, can you route this board in such a way that only those signals run into that area of the board.

    Plus what is the likelihood that cutting/breaking the board could create signal breaks or short or slight changes in signals... So suppose Paul did that, how many boards should we try to snap off the end would we need to do, in order to have a confidence level, that it did not completely screw things up...

    Multiple Rows:
    As for two rows, as mentioned you can not populate both rows and have it work on breadboard. However you can not do that today with T3.2 with bottom pads either. So as long as one understands the limitations...

    My Preferences:
    Make the layout of it as compatible with the T3.5/6, especially for all through hole connections, including the USB. That way in many cases one might be able to swap this new chip into boards created for the 3.6... Sort of like the FRDM castellated board converts the current T4 into that size package. If one or two DAC pins are added, it would be great if they went to where the DAC is on T3.6...

    Edit: also if space is available, maybe pins that correspond to the position of A10 and A11 on T3.5/6.

    As for additional pins that might be added beyond what fits into top pins... I am torn.

    One obvious choice is to see if we could add SMT pins on the bottom that align with one of the T3.6. Might in some cases be subsets, like if issue of getting the full 2x5 on end and a 2x4 works...

    Other option is to add additional Rows or columns of pins. But if for example if this changes the dimensions to be bigger than T3.6, this could easily cause it to not be a drop in replacement, as there may not be space on a current board.

    @Paul - But my strongest preference, is that it is a simple enhancement of the current T4, that does not require too much of your development time and testing time, such that you can start having the fun to figure out that next board with two different cores...

    But again that is only my $.02
    Last edited by KurtE; Today at 02:38 AM.

  6. #31
    My .02

    Keep it simple. Make the T4 in T3.6 format. Have a uSD holder and bring D24 to D33 to the through holes.

  7. #32
    Junior Member
    Join Date
    Nov 2019
    Quote Originally Posted by skpang View Post
    Having only one row on each side means you can plug into a breadboard. Two rows you can't.
    At this time with the new Teensy 4.0 you can not use many pins with a breadboard, because they are on the back side :-)

    Outer 2nd Row: Breadboard is not a big problem... use an adapter board for breadboards (outer row with headers upside), or no adapter with headers upside for the outer row, and a 2nd Teensy for PCBs

    I think it would be better to go new ways. Old ways are too limited. An option were 2 versions, new and old.

    The good thing with the 2 rows is... you never have to solder anything on the back (PCB friendly :-)

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