Read a chunk of data from persistent memory.

        Parameters
        ----------
        address : int
            Address in persistent memory (e.g., EEPROM).
        count : int, optional
            Number of values to read.

            If not set, read a single value of the specified :data:`dtype`.
        dtype : numpy.dtype, optional
            The type of the value(s) to read.

        Returns
        -------
        dtype or numpy.array(dtype=dtype)
            If :data:`count` is ``None``, return single value.

            Otherwise, return array of values.

def persistent_read_multibyte(self, address, count=None, dtype=np.uint8):
        '''
        Read a chunk of data from persistent memory.

        Parameters
        ----------
        address : int
            Address in persistent memory (e.g., EEPROM).
        count : int, optional
            Number of values to read.

            If not set, read a single value of the specified :data:`dtype`.
        dtype : numpy.dtype, optional
            The type of the value(s) to read.

        Returns
        -------
        dtype or numpy.array(dtype=dtype)
            If :data:`count` is ``None``, return single value.

            Otherwise, return array of values.
        '''
        nbytes = np.dtype(dtype).itemsize
        if count is not None:
            nbytes *= count

        # Read enough bytes starting at specified address to match the
        # requested number of the specified data type.
        data_bytes = np.array([self.persistent_read(address + i)
                               for i in xrange(nbytes)], dtype=np.uint8)

        # Cast byte array as array of specified data type.
        result = data_bytes.view(dtype)

        # If no count was specified, we return a scalar value rather than the
        # resultant array.
        if count is None:
            return result[0]
        return result