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mcbsp的spi从模式

yinfei feng
Intellectual 604 points

设计一个stm32和dsp28335之间的spi通信，想实现一个片选信号cs电平变化的过程传多次数据。即主机cs电平一直拉低，然后与从机一直传输数据，从机为dsp，采用接收中断的方式。但是发现cs电平的一次变化只能传一次数据。

总结一下就是在每次发送数据前都要对spi进行片选使能，为什么不能一次选中，之后进行多次的传输？

mcbsp配置

按照如图所示的配置：

McbspbRegs.SPCR1.bit.RINTM = 2;// 设置为cs低电平触发
McbspbRegs.MFFINT.bit.RINT = 1;//打开接受中断

  • 0
    Intellectual 604 points

    一次传输多个数据时，会出现rrdy位不置位的现象？这是为什么？

  • 0
    TI__Guru 60308 points

    The SPISTE pin operates as the slave-select pin. An active-low signal on the SPISTE pin allows the slave
    SPI to transfer data to the serial data line; an inactive- high signal causes the slave SPI serial shift register
    to stop and its serial output pin to be put into the high-impedance state. This allows many slave devices to
    be tied together on the network, although only one slave device is selected at a time

    如果不把电平拉高，就一直发送数据。

    ERIC