DSP TMS320F28335 SPI读写 flash W25X20_dsp28335外接flash

SPI IO初始化

void 
InitSpiaGpio()
{
    EALLOW;
    
    //
    // Enable internal pull-up for the selected pins
    // Pull-ups can be enabled or disabled by the user.  
    // This will enable the pullups for the specified pins.
    // Comment out other unwanted lines.
    //
    GpioCtrlRegs.GPAPUD.bit.GPIO16 = 0;   //Enable pull-up on GPIO16 (SPISIMOA)
    GpioCtrlRegs.GPAPUD.bit.GPIO17 = 0;   //Enable pull-up on GPIO17 (SPISOMIA)
    GpioCtrlRegs.GPAPUD.bit.GPIO18 = 0;   //Enable pull-up on GPIO18 (SPICLKA)
    GpioCtrlRegs.GPAPUD.bit.GPIO19 = 0;   //Enable pull-up on GPIO19 (SPISTEA)
 
    //GpioCtrlRegs.GPBPUD.bit.GPIO54 = 0; //Enable pull-up on GPIO54 (SPISIMOA)
    //GpioCtrlRegs.GPBPUD.bit.GPIO55 = 0; //Enable pull-up on GPIO55 (SPISOMIA)
    //GpioCtrlRegs.GPBPUD.bit.GPIO56 = 0; //Enable pull-up on GPIO56 (SPICLKA)
    //GpioCtrlRegs.GPBPUD.bit.GPIO57 = 0; //Enable pull-up on GPIO57 (SPISTEA)
 
    //
    // Set qualification for selected pins to asynch only
    // This will select asynch (no qualification) for the selected pins.
    // Comment out other unwanted lines.
    //
//    GpioCtrlRegs.GPAQSEL2.bit.GPIO17 = 0; // Asynch input GPIO16 (SPISIMOA)
//    GpioCtrlRegs.GPADIR.bit.GPIO17 = 0;
 
    GpioCtrlRegs.GPAQSEL2.bit.GPIO16 = 3; // Asynch input GPIO16 (SPISIMOA)
    GpioCtrlRegs.GPAQSEL2.bit.GPIO17 = 3; // Asynch input GPIO17 (SPISOMIA)
    GpioCtrlRegs.GPAQSEL2.bit.GPIO18 = 3; // Asynch input GPIO18 (SPICLKA)
    GpioCtrlRegs.GPAQSEL2.bit.GPIO19 = 3; // Asynch input GPIO19 (SPISTEA)
 
    //GpioCtrlRegs.GPBQSEL2.bit.GPIO54 = 3; // Asynch input GPIO16 (SPISIMOA)
    //GpioCtrlRegs.GPBQSEL2.bit.GPIO55 = 3; // Asynch input GPIO17 (SPISOMIA)
    //GpioCtrlRegs.GPBQSEL2.bit.GPIO56 = 3; // Asynch input GPIO18 (SPICLKA)
    //GpioCtrlRegs.GPBQSEL2.bit.GPIO57 = 3; // Asynch input GPIO19 (SPISTEA)
 
    //
    // Configure SPI-A pins using GPIO regs
    // This specifies which of the possible GPIO pins will be SPI 
    // functional pins.
    // Comment out other unwanted lines.
    //
    GpioCtrlRegs.GPAMUX2.bit.GPIO16 = 1; // Configure GPIO16 as SPISIMOA
    GpioCtrlRegs.GPAMUX2.bit.GPIO17 = 1; // Configure GPIO17 as SPISOMIA
    GpioCtrlRegs.GPAMUX2.bit.GPIO18 = 1; // Configure GPIO18 as SPICLKA
    GpioCtrlRegs.GPAMUX2.bit.GPIO19 = 1; // Configure GPIO19 as SPISTEA
 
    //GpioCtrlRegs.GPBMUX2.bit.GPIO54 = 1; // Configure GPIO54 as SPISIMOA
    //GpioCtrlRegs.GPBMUX2.bit.GPIO55 = 1; // Configure GPIO55 as SPISOMIA
    //GpioCtrlRegs.GPBMUX2.bit.GPIO56 = 1; // Configure GPIO56 as SPICLKA
    //GpioCtrlRegs.GPBMUX2.bit.GPIO57 = 1; // Configure GPIO57 as SPISTEA
 
    EDIS;
}

初始化SPIA相关寄存器

void InitSpia(void)
{
	SpiaRegs.SPICCR.bit.SPISWRESET = 0; //SPI复位
 
	//数据在时钟上升沿发送，在时钟下降沿所存输入的数据
	SpiaRegs.SPICCR.bit.CLKPOLARITY = 0; //上升沿触发
	SpiaRegs.SPICTL.bit.CLK_PHASE = 1; //延时时钟
 
	SpiaRegs.SPICCR.bit.SPILBK = 0; //禁止内部回路
	SpiaRegs.SPICCR.bit.SPICHAR = 0xF; //发送和接收的数据长度16
 
	SpiaRegs.SPICTL.bit.OVERRUNINTENA = 0; //关闭溢出中断
	SpiaRegs.SPICTL.bit.MASTER_SLAVE = 1; //主控制器模式
	SpiaRegs.SPICTL.bit.TALK = 1; //使能发送功能
	SpiaRegs.SPICTL.bit.SPIINTENA = 0; //禁止SPI中断
 
	SpiaRegs.SPIBRR = 0x63; //波特率=150M/4/100=375K
 
	SpiaRegs.SPIPRI.bit.FREE = 1; //仿真不影响发送数据
 
	SpiaRegs.SPICCR.bit.SPISWRESET = 1; //SPI功能恢复
}

SPI 轮询发送与接受

void spi_xmit(Uint16 a)
{
 
    SpiaRegs.SPITXBUF=a;//左对齐
    while(SpiaRegs.SPISTS.bit.BUFFULL_FLAG){}
 
    g_wData[0] = SpiaRegs.SPIRXBUF;
    while(SpiaRegs.SPIFFRX.bit.RXFFST != 0);
 
    SpiaRegs.SPITXBUF=0XFFFF;//左对齐
    while(SpiaRegs.SPISTS.bit.BUFFULL_FLAG){}
 
    g_wData[1] = SpiaRegs.SPIRXBUF;
    while(SpiaRegs.SPIFFRX.bit.RXFFST != 0);
 
    SpiaRegs.SPITXBUF=0XFFFF;//左对齐
    while(SpiaRegs.SPISTS.bit.BUFFULL_FLAG){}
 
    g_wData[2] = SpiaRegs.SPIRXBUF;
    while(SpiaRegs.SPIFFRX.bit.RXFFST != 0);
 
    SpiaRegs.SPITXBUF=0XFFFF;//左对齐
    while(SpiaRegs.SPISTS.bit.BUFFULL_FLAG){}
 
    g_wData[3] = SpiaRegs.SPIRXBUF;
    while(SpiaRegs.SPIFFRX.bit.RXFFST != 0);
 
    SpiaRegs.SPITXBUF=0XFFFF;//左对齐
    while(SpiaRegs.SPISTS.bit.BUFFULL_FLAG){}
 
    g_wData[4] = SpiaRegs.SPIRXBUF;
    while(SpiaRegs.SPIFFRX.bit.RXFFST != 0);
 
    SpiaRegs.SPITXBUF=0XFFFF;//左对齐
    while(SpiaRegs.SPISTS.bit.BUFFULL_FLAG){}
 
    g_wData[5] = SpiaRegs.SPIRXBUF;
    while(SpiaRegs.SPIFFRX.bit.RXFFST != 0);
//
    g_wData[6] = SpiaRegs.SPIRXBUF;
	while(SpiaRegs.SPIFFRX.bit.RXFFST != 0);
 
}

波形（发送0x9f）查询JEDEC ID编码回复0xEF 0X3012

绿色：SPI_MOSI

黄色：SPI_CS

紫色：SPI_MISO

蓝色：SPI_CLK