6000a6205a
Linking to API material requires knowing the pecularities of how doxygen, sphinx, and breathe work. In an attempt to hide some of this we're preparing the current docs to allow use of configuration defaults that will let us more simply use a default role that will hunt for a reference target in the various domains that are available by using a default "role" of "all". This will let us use the simple notation `functionname` or `typename` without fully specifying the reference as :c:func:`functionname`. This patch cleans up exising docs that were (incorrectly) using single backtics where double backtics should have been used, and also found some typos (such as a space between the role name and the reference, such as :file: `filename`, and a missing colon such as c:func:`functionname`) This is a start to address issue #14313 Signed-off-by: David B. Kinder <david.b.kinder@intel.com>
55 lines
1.6 KiB
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55 lines
1.6 KiB
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.. _SDHC_disks:
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SDHC disks
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##########
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Zephyr includes support for connecting an SDHC card via the SPI bus.
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This can be used with Zephyr's built-in filesystem support to read and
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write FAT formatted cards.
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The system has been tested with cards from Samsung, SanDisk, and 4V
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with sizes from 2 GiB to 32 GiB in single partition mode. Higher
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capacity cards should also work but haven't been tested. Please let
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us know if they work!
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MMC and SDSC (<= 2 GiB) cards are not supported and will be ignored.
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.. note:: The system does not support inserting or removing cards while the
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system is running. The cards must be present at boot and must not be
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removed. This may be fixed in future releases.
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FAT filesystems are not power safe so the filesystem may become
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corrupted if power is lost or if the card is removed.
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Enabling
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********
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For example, this device tree fragment adds an SDHC card slot on ``spi1``,
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uses ``PA27`` for chip select, and runs the SPI bus at 24 MHz once the
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SDHC card has been initialized:
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.. code-block:: none
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&spi1 {
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status = "ok";
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cs-gpios = <&porta 27 0>;
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sdhc0: sdhc@0 {
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compatible = "zephyr,mmc-spi-slot";
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reg = <0>;
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status = "ok";
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label = "SDHC0";
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spi-max-frequency = <24000000>;
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};
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};
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Usage
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*****
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The SDHC card will be automatically detected and initialized by the
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filesystem driver when the board boots.
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To read and write files and directories, see the :ref:`file_system` in
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:zephyr_file:`include/fs.h` such as :c:func:`fs_open()`,
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:c:func:`fs_read()`, and :c:func:`fs_write()`.
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