SD card wire



  • hi,

    i try to understand sd card connections to WIpy2.0 without expansion board
    alt text

    but i am confused about pinout and docs
    in pinout i have
    P12 MOSI
    P11 MISO
    P23 sdCLK
    P4 sdCMD???

    in docs:
    https://docs.pycom.io/pycom_esp32/library/machine.SD.html
    P8: DAT0, P23: SCLK and P4: CMD no external pull-up resistors are needed.
    why P8?

    normally i will be connect as:

    MOSI - P12
    MISO - P11
    SCK - P23
    CS to "any pin"
    

    how to really connect this spi device?



  • Finally got it - this was so simple :)
    here is really good overview if someone start like i with SD playing
    http://www.ti.com/lit/an/slaa281b/slaa281b.pdf



  • @livius
    i reply myself ;-)
    i see that i misunderstand doc - doc is about direct access to sd
    by sd interface to dat0
    alt text

    Do i understand this now corectly? Can someone point me?
    And more question in doc is:
    and the current implementation only works in 1-bit mode
    what limitation it create? And when it will be changed?
    I am new in sd card interface.

    UPDATE
    I understand now 1-bit mode
    there are also 4 bit mode - but 1 bit is enough for start playing


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