TMS320F28377D: 使用28377D的GPIO复用为SPI的片选引脚与将GPIO设置为输出的区别？

Junjie Huang

Part Number: TMS320F28377D

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    GpioCtrlRegs.GPBGMUX2.bit.GPIO60 = 1; // Configure GPIO60 as SPISIMOB
    GpioCtrlRegs.GPBMUX2.bit.GPIO60 = 2;
//  GpioCtrlRegs.GPAMUX1.bit.GPIO5 = 2;  // Configure GPIO5 as SPISIMOA
    GpioCtrlRegs.GPBGMUX2.bit.GPIO61 = 1; // Configure GPIO61 as SPISOMIB
    GpioCtrlRegs.GPBMUX2.bit.GPIO61 = 2;
//  GpioCtrlRegs.GPAMUX1.bit.GPIO3 = 2;  // Configure GPIO3 as SPISOMIA
    GpioCtrlRegs.GPBGMUX2.bit.GPIO58 = 1; // Configure GPIO58 as SPICLKB
    GpioCtrlRegs.GPBMUX2.bit.GPIO58 = 2;
//    GpioCtrlRegs.GPBGMUX2.bit.GPIO59 = 1; // Configure GPIO19 as SPISTEA
    GpioCtrlRegs.GPBMUX2.bit.GPIO59 = 0;//设置GPIO59为普通IO口
    GpioCtrlRegs.GPBDIR.bit.GPIO59 = 1;//设置为输出模式
    GpioDataRegs.GPBSET.bit.GPIO59 = 1;//设置输出高电平
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    GpioCtrlRegs.GPBGMUX2.bit.GPIO60 = 1; // Configure GPIO60 as SPISIMOB
    GpioCtrlRegs.GPBMUX2.bit.GPIO60 = 2;
//  GpioCtrlRegs.GPAMUX1.bit.GPIO5 = 2;  // Configure GPIO5 as SPISIMOA
    GpioCtrlRegs.GPBGMUX2.bit.GPIO61 = 1; // Configure GPIO61 as SPISOMIB
    GpioCtrlRegs.GPBMUX2.bit.GPIO61 = 2;
//  GpioCtrlRegs.GPAMUX1.bit.GPIO3 = 2;  // Configure GPIO3 as SPISOMIA
    GpioCtrlRegs.GPBGMUX2.bit.GPIO58 = 1; // Configure GPIO58 as SPICLKB
    GpioCtrlRegs.GPBMUX2.bit.GPIO58 = 2;
//    GpioCtrlRegs.GPBGMUX2.bit.GPIO59 = 1; // Configure GPIO19 as SPISTEA
    GpioCtrlRegs.GPBMUX2.bit.GPIO59 = 0;//设置GPIO59为普通IO口
    GpioCtrlRegs.GPBDIR.bit.GPIO59 = 1;//设置为输出模式
    GpioDataRegs.GPBSET.bit.GPIO59 = 1;//设置输出高电平

网上看到有一个例子里面对GPIO复用为SPI的操作，里面是将SPI片选的GPIO引脚直接设置为输出，并没有复用为SPISTEA。请问将GPIO设置为输出跟GPIO复用为SPISTEx的作用是一样的吗？是不是只要开启SPI，复用为SPISTEx的GPIO其实内部就是将GPIO设置为输出，然后在进行数据发送时会自动拉高拉低？或者说只要SPI开启并且片选引脚是设置为GPIO输出，在发送数据时就会自动将此引脚拉高或拉低？

2 年多前