:class:`SPI` --- 串行外设接口总线协议(master side)
=======================================

类
-------

.. class:: SPI(...)


使用示例::

   import haascv
   from haascv import driver

   spiObj = driver.spi();#获取SPI类对象
   spiObj.open(0, spiObj.DRIVER_SPI_MODE_MASTER, 2000000, 0)#打开SPI模块

   spi_read_buf = bytearray(4)#定义存储读取数据的对象
   spi_write_buf = bytearray([0x01, 0x02, 0x10, 0xaa])#定义待写的数据

   print(spi_write_buf)#打印写的buffer
   spiObj.write(spi_write_buf)#开发发送数据

   spiObj.read(spi_read_buf)#读取数据
   print(spi_read_buf)#打印读取的数据

   spiObj.writeAndRead(spi_write_buf, spi_read_buf)#发送并读取数据
   print(spi_read_buf)#打印读取的数据内容

   spiObj.close()#关闭spi模块


常量
---------


.. data:: SPI可配置的模式:

        .. data:: DRIVER_SPI_MODE_MASTER
        .. data:: DRIVER_SPI_MODE_MASTER_2
        .. data:: DRIVER_SPI_MODE_MASTER_4
        .. data:: DRIVER_SPI_MODE_MASTER_8
        .. data:: DRIVER_SPI_MODE_SLAVE 


操作函数
-------

.. method:: open(port,role_mode, freq, priv)

        打开SPI模块

.. method:: write(spi_write_buf)

        开发发送数据

.. method:: ead(spi_read_buf)

        读取数据

.. method:: writeAndRead(spi_write_buf, spi_read_buf)

        发送并读取数据

.. method:: close()

        关闭SPI模块