micropython/docs/library/pyb.Flash.rst

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