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Thread: Migrating from Mega 2560 to Teensy 3.6

  1. #1
    Junior Member
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    Migrating from Mega 2560 to Teensy 3.6

    I recently picked up a Teensy 3.6 and am trying to figure out how to jump to it with my existing library. Currently have 896 sk6812 RGBW LEDs in one "strand" that exists on 14 panels of 64 LED each (think checkerboard for layout).

    I currently have the Teensy on a breadboard, with pin 0 (ground) grounded to same ground as the LEDs (which are powered by 60amp power supply, distributed to LEDs in 6 different places - keep in mind this all works on the Mega, so most of the wiring should still be good). And a ... I wanna say 450ohm?? resistor from pin 10 of the Teensy, to the data line. The resistor is green, blue, brown, gold. But when I power everything on, nothing happens. Board is not shot, as I can still put the "blink" sketch on. But loading my custom sketch, I get nothing.

    Are certain pins dedicated or better suited? I was using pin 10 on my old board, so figured I'd be able to use the same. I'm using Neopixel library by Adafruit. Will the correct "version" of that library (I heard there is a different one for Teensy?) be included? I could not find a way to determine which one it is.

    I've considered trying to use the Octo library, but not yet interested in breaking up my large display into multiple strands, as that would be a somewhat difficult thing to undo if it doesn't work out. Want to see if I can drive all 896 in one strand first, and hoping to get some performance gains from the old Mega.

    Any ideas? Is the output of the data sufficient? I can't tell if the Mega output 3.3 or 5v. I assume the Teensy is 3.3. I also don't know what the sk6812 even expects. Feeling a bit lost. Happy to upload images or sketches if it would be of any help.

  2. #2
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    you might need a 5V buffer like the OctoWS board comes with to drive 5V to some strips, mega drives them at 5V but teensy drives at 3.3V

  3. #3
    Senior Member+ Frank B's Avatar
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    Datasheets are a good source of information
    https://cdn-shop.adafruit.com/produc...datasheet+.pdf

    Page 3 tells us: Input Voltage: 5V, Logic High:3.4V
    Teensy outputs 3.3 Volt.
    -> You need a Levelshifter. Maybe a 74HCT245 works?
    Last edited by Frank B; 12-26-2018 at 05:38 PM.

  4. #4
    Senior Member+ Frank B's Avatar
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    Ok, double post. We don't like that. Closing here. Please stop that in the future.

    https://forum.pjrc.com/threads/53543...l=1#post193673

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