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53 lines
1.8 KiB
53 lines
1.8 KiB
5 years ago
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.. currentmodule:: pyb
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.. _pyb.Flash:
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class Flash -- access to built-in flash storage
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===============================================
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The Flash class allows direct access to the primary flash device on the pyboard.
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In most cases, to store persistent data on the device, you'll want to use a
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higher-level abstraction, for example the filesystem via Python's standard file
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API, but this interface is useful to :ref:`customise the filesystem
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configuration <filesystem>` or implement a low-level storage system for your
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application.
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Constructors
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------------
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.. class:: pyb.Flash()
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Create and return a block device that represents the flash device presented
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to the USB mass storage interface.
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It includes a virtual partition table at the start, and the actual flash
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starts at block ``0x100``.
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This constructor is deprecated and will be removed in a future version of MicroPython.
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.. class:: pyb.Flash(\*, start=-1, len=-1)
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Create and return a block device that accesses the flash at the specified offset. The length defaults to the remaining size of the device.
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The *start* and *len* offsets are in bytes, and must be a multiple of the block size (typically 512 for internal flash).
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Methods
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-------
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.. method:: Flash.readblocks(block_num, buf)
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.. method:: Flash.readblocks(block_num, buf, offset)
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.. method:: Flash.writeblocks(block_num, buf)
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.. method:: Flash.writeblocks(block_num, buf, offset)
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.. method:: Flash.ioctl(cmd, arg)
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These methods implement the simple and :ref:`extended
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<block-device-interface>` block protocol defined by
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:class:`uos.AbstractBlockDev`.
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Hardware Note
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-------------
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On boards with external spiflash (e.g. Pyboard D), the MicroPython firmware will
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be configured to use that as the primary flash storage. On all other boards, the
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internal flash inside the :term:`MCU` will be used.
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