DSP28335的SCI标准模式非FIFO使用

目录

1. SCI标准模式下发送

2. SCI标准模式下接收

3. 示例说明

---

1. SCI标准模式下发送

1. ScibRegs.SCITXBUF = ‘A’;
2. 在ScibRegs.SCICTL2.bit.TXEMPTY=1之后SCITXBUF中的数据自动到TXSHF（移位寄存器中）
3. TXSHF移位到硬件引脚TXD

2. SCI标准模式下接收

1. 数据到达RXD引脚之后，检测启动位
2. TXSHF移位到ScibRegs.SCIRXBUF当中，产生一个中断申请
3. ScibRegs.SCIRXST.bit.RXRDY标志位置1，表示接收到一个字节
4. 通过读取g_recv_buff[s_recv_count++] =ScibRegs.SCIRXBUF.all,标志位RXRDY自动清除

3. 示例说明

void main(void)
{
    char *msg;
    InitSysCtrl();

    InitScibGpio();  //GPIO14、GPIO15

    DINT;

    InitPieCtrl();

    IER = 0x0000;
    IFR = 0x0000;

    InitPieVectTable();

    EALLOW;
    PieVectTable.SCIRXINTB = &scibRxIsr;
//    PieVectTable.SCITXINTB = &scibTxIsr;
    EDIS;

    PieCtrlRegs.PIECTRL.bit.ENPIE = 1;   // Enable the PIE block
    PieCtrlRegs.PIEIER9.bit.INTx3=1;     // PIE Group 9, INT3
//    PieCtrlRegs.PIEIER9.bit.INTx4=1;     // 发送中断没必要开启
    IER = M_INT9; // Enable CPU INT
    EINT;

    scib_fifo_init();	   // Initialize the SCI
    scib_echoback_init();  // Initalize SCI for echoback

    msg = "Hello World!\n\0";
    scib_msg(msg,strlen(msg));

    for(;;)
}
/*
初始化SCIB
*/
void scib_echoback_init()
{
// 	ScibRegs.SCICCR.all =0x0007;   //等价于下面的5条语句
 	ScibRegs.SCICCR.bit.STOPBITS = 0;       //1 stop bit
 	ScibRegs.SCICCR.bit.PARITYENA = 0;      //NO PARITY
 	ScibRegs.SCICCR.bit.LOOPBKENA = 0;      //No loopback 1-自测模式即硬件内部收发引脚连在一起
 	ScibRegs.SCICCR.bit.ADDRIDLE_MODE = 0;  //地址协议选择空闲线协议，1-选择地址位协议
 	ScibRegs.SCICCR.bit.SCICHAR = 7;        //数据位8位

	ScibRegs.SCICTL1.bit.RXENA = 1;//使能接收
	ScibRegs.SCICTL1.bit.TXENA = 1;//使能发送

//	ScibRegs.SCICTL2.bit.TXINTENA =1;   //发送中断禁用使能
	ScibRegs.SCICTL2.bit.RXBKINTENA =1; //接收中断使能
	//波特率设置寄存器BRR = LSPCLK/(波特率*8)-1
	#if (CPU_FRQ_150MHZ)
	      ScibRegs.SCIHBAUD    =0x0001;  // 9600 baud @LSPCLK = 37.5MHz.
	      ScibRegs.SCILBAUD    =0x00E7;
	#endif
	ScibRegs.SCICTL1.bit.SWRESET =1;    // 通过写1重新使能SCI，该复位每种外设都有
}
void scib_xmit(char a)
{
    ScibRegs.SCITXBUF=a;
    while(ScibRegs.SCICTL2.bit.TXEMPTY == 0){;}//等待发送结束，否则会覆盖之前要发送的内容
}


void scib_msg(char * msg, Uint16 len)
{
    int i;
    for(i = 0;i < len;i++)
    {
        scib_xmit(msg[i]);
    }
}
/*
其实该函数没必要写，默认初值就是如此；这里写上是为了加深理解
*/
void scib_fifo_init()
{
    ScibRegs.SCIFFTX.bit.TXFFIENA = 0;//禁用FIFO
}

__interrupt void scibRxIsr(void)
{
    static unsigned char s_recv_count = 0;
    g_recv_buff[s_recv_count++] =ScibRegs.SCIRXBUF.all;     // Read data

    if(s_recv_count >= 255)
        s_recv_count = 0;

    PieCtrlRegs.PIEACK.all|=0x100;       // Issue PIE ack
}