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Thread: sd card + SPIFIFO or spi4teensy3

  1. #1

    sd card + SPIFIFO or spi4teensy3

    hi.

    is it possible to use any of these two SPI libraries to read data of an SD card?

    i am currently using <SPI.h> and <SdFat.h> successfully on my teens 3.1.
    but i was hoping to try the faster libraries.

    thanks,stephan.

  2. #2
    Senior Member
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    Based no numerous threads I'd believe that SDFat is about as fast as you can get.
    The rest depends on writing to the SD card in larger blocks e.g. 512 bytes rather than byte wise.

  3. #3
    i see. thanks for taking the time.

  4. #4
    Senior Member PaulStoffregen's Avatar
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    Have you done any measurements of the actual speed you're getting?

    If you're reading multiple files, or seeking within a file, have you tried measuring the speed on different cards? For sequential access, they're all pretty similar, but when you start reading from more than one location, there's a pretty huge difference between cards. The "class 10" and other markings on the cards are pretty much worthless, since they're only about sequential speed. Many of the slowest random access cards are rated "class 10".

  5. #5
    i have 13 SPI device in total, one of which is an SD card, the others are these LCD buttons: http://ca-en.alliedelec.com/search/p...x?SKU=70192511

    i wanted to see if a fast SPI bus would remove some of the image problems i am seeing.
    so, it's not so much about fast sd card reading.

    but al your input is much appreciated.
    s.

  6. #6
    Senior Member PaulStoffregen's Avatar
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    Oh my, is there an open source library for those buttons?

    If so, I believe PJRC is going to need to buy some of those for me to play with!!!!

  7. #7
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    Ohh my ... $70 a piece. But yeah, awesome stuff!

  8. #8
    Administrator Robin's Avatar
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    Quote Originally Posted by PaulStoffregen View Post
    Oh my, is there an open source library for those buttons?

    If so, I believe PJRC is going to need to buy some of those for me to play with!!!!

    And there goes the R&D budget...

  9. #9
    true. budget is spent. everything does work well, on my first proto PCB. but the next version (smaller) seemed to have introduced some noise on the data line and one of the screens sometimes has an image error.
    that's why i thought a fast SPI might be good to try.
    or to have the sd card on a separate spi buss.

  10. #10
    here is the code: https://github.com/antimodular/nkk_lcd_smartswitch
    which is used for this artwork: http://lozano-hemmer.com/nineteen_eighty-four.php

    if anyone wants to take it to the next level, please do so and share the code too.

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