kopia lustrzana https://github.com/micropython/micropython
57 wiersze
2.8 KiB
ReStructuredText
57 wiersze
2.8 KiB
ReStructuredText
.. _storage_zephyr:
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Filesystems and Storage
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=======================
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Storage modules support virtual filesystem with FAT and littlefs formats, backed by either
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Zephyr DiskAccess or FlashArea (flash map) APIs depending on which the board supports.
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See `vfs Filesystem Mounting <https://docs.micropython.org/en/latest/library/vfs.html?highlight=vfs#filesystem-mounting>`_.
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Disk Access
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-----------
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The :ref:`zephyr.DiskAccess <zephyr.DiskAccess>` class can be used to access storage devices, such as SD cards.
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This class uses `Zephyr Disk Access API <https://docs.zephyrproject.org/latest/reference/storage/disk/access.html>`_ and
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implements the `vfs.AbstractBlockDev` protocol.
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For use with SD card controllers, SD cards must be present at boot & not removed; they will
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be auto detected and initialized by filesystem at boot. Use the disk driver interface and a
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file system to access SD cards via disk access (see below).
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Example usage of FatFS with an SD card on the mimxrt1050_evk board::
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import os
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from zephyr import DiskAccess
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bdev = zephyr.DiskAccess('SDHC') # create block device object using DiskAccess
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os.VfsFat.mkfs(bdev) # create FAT filesystem object using the disk storage block
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os.mount(bdev, '/sd') # mount the filesystem at the SD card subdirectory
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with open('/sd/hello.txt','w') as f: # open a new file in the directory
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f.write('Hello world') # write to the file
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print(open('/sd/hello.txt').read()) # print contents of the file
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Flash Area
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----------
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The :ref:`zephyr.FlashArea <zephyr.FlashArea>` class can be used to implement a low-level storage system or
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customize filesystem configurations. To store persistent data on the device, using a higher-level filesystem
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API is recommended (see below).
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This class uses `Zephyr Flash map API <https://docs.zephyrproject.org/latest/reference/storage/flash_map/flash_map.html#>`_ and
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implements the `vfs.AbstractBlockDev` protocol.
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Example usage with the internal flash on the reel_board or the rv32m1_vega_ri5cy board::
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import os
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from zephyr import FlashArea
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bdev = FlashArea(FlashArea.STORAGE, 4096) # create block device object using FlashArea
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os.VfsLfs2.mkfs(bdev) # create Little filesystem object using the flash area block
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os.mount(bdev, '/flash') # mount the filesystem at the flash storage subdirectory
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with open('/flash/hello.txt','w') as f: # open a new file in the directory
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f.write('Hello world') # write to the file
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print(open('/flash/hello.txt').read()) # print contents of the file
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For boards such as the frdm_k64f in which the MicroPython application spills into the default flash storage
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partition, use the scratch partition by replacing ``FlashArea.STORAGE`` with the integer value 4.
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