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Thread: Trying to run SSD1351 dispay with SD adapter on Teensy 3.2

  1. #1
    Junior Member
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    Jun 2018
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    Trying to run SSD1351 dispay with SD adapter on Teensy 3.2

    Hello! I'm trying to run SSD1351 display along with the SD card adapter, on a Teensy 3.2.
    I'm using this library for the display https://github.com/kirberich/teensy_ssd1351, which is using the fast SPI fifo stuff from https://github.com/PaulStoffregen/ILI9341_t3.
    For the SD, I'm using the default arduino SD library.
    Both the display and the SD adapter run perfectly fine alone, but when wired together the display just blanks out after a few dozen writes to the SD :\
    This seems to happen regardless of the SPI clock speed (fast or slow), but it happens "faster" if I write faster, and "slower" if I write slower.
    I think I'm messing something up with the SS signal, I suspect the display is holding it's SS active during the SD transactions and perhaps getting confused?
    I don't understand the fifo magic very well in the display library, but does anyone happen to know if it would conflict with other SPI devices? Or perhaps how to raise the SS signal using fifo? (to disable the display from getting hammered)

    Any ideas would be appreciated!

    Thank you,
    Anton

  2. #2
    Senior Member+ MichaelMeissner's Avatar
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    If you haven't already done so, please look at the following document:


    Note, it appears the standard SD library does not use SPI.beginTransaction, but if you switch to use SD_t3.h, it may work better (or not, I don't know the code).

    A quick glance at the code says that if you edit the library include file SD_t3.h, and un-comment the line with #define USE_TEENSY3_OPTIMIZED_CODE, it may work better. Note, using this method means that you can only read from the SD card, not write to it.

    There may be other SD drivers that might work.
    Last edited by MichaelMeissner; 08-26-2019 at 03:10 PM.

  3. #3
    Junior Member
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    Jun 2018
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    Thank you (and Paul!), adding the pullup resistors to CS did the trick!

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