.. module:: spiflash

********
SpiFlash
********

This modules handles operations on a generic Spi Flash Memory.
The following operations are allowed:

    * read/write data;
    * check if flash is busy;
    * enable write operations;
    * erase sector;
    * erase chip.

    
==============
SpiFlash class
==============

.. class:: SpiFlash(drvname, cs, clock=1000000)

        Initialize an external Flash memory specifying its:

            * MCU SPI circuitry *drvname* (one of SPI0, SPI1, ... check pinmap for details);
            * chip select pin *cs*;
            * clock *clock*, default at 1MHz.

    
.. method:: write_enable()

        Enable write operations.
        Automatically called by :meth:`write_data`, :meth:`erase_sector`, :meth:`chip_erase` methods.

        
.. method:: is_write_busy()

        Returns 1 or 0 depending on whether the Flash is busy or not.

        
.. method:: write_data(addr, data)

        Write data *data* starting from address *addr*.
        *data* can be a bytearray or a list of integers less than 256.

        :meth:`erase_sector` MUST be called before writing data in a sector.

        Writing is also allowed via bracket notation. The following is valid syntax: ::

            my_flash[addr] = data

        
.. method:: erase_sector(addr)

        Erase a whole sector passing the *addr* address of any byte contained in it.
        All sector bytes set to 0xff.

        
.. method:: read_data(addr, n=1)

        Read *n* bytes of data starting from address *addr*.

        Reading is also allowed via bracket notation. The following is valid syntax: ::

            my_data = my_flash[addr:addr+n]

        
.. method:: chip_erase()

        Erase the whole memory.
        All memory bytes set to 0xff.

        
.. method:: chip_id(n)

        Returns the bytes representation of the flash chip unique identifier.
        The length in bytes of the chip id must be passed as argument *n*.