gpio.c

微机通过串口通信精确控制pwm频率和脉宽。

#define  ss 7
#include "DSP28_Device.h"
#include "stdlib.h"

interrupt void ISRTimer1(void) ;
interrupt void sci_rx_isr(void);
void delayus(unsigned long m);
void sci_init(void);
//全局变量定义；
char buffer[ss];
long width=10,t=20000;//width脉宽,t低电平的时间
unsigned long i=0;
int freq=50,k,h;//freq频率,h计数输入字符的位数
long count=0,count1=0;//计数脉冲个数，count1记忆功能
float t1;//中间计算周期用的
char a;//接收中断中读取第一个字符.
int zz=0;//停止标志位
int type=1;//极性选择
void main(void)
{ 
	InitSysCtrl();
	InitGpio();
	DINT;
	IER = 0x0000;
	IFR = 0x0000;
	InitPieCtrl(); 
	InitPieVectTable();
	InitPeripherals(); 
	sci_init();
	EALLOW;
	PieVectTable.RXAINT = &sci_rx_isr;
	PieVectTable.T1PINT = &ISRTimer1;
	EDIS; 
	PieCtrl.PIEIER9.bit.INTx1=1;
	IER|=0x100;
	EINT;
	ERTM;
	EvaRegs.T1CON.all=EvaRegs.T1CON.all|0x0040; //启动Timer1
    while(1)
    {
    //尚未开始工作，等待状态
	    if(count==0||zz==0)
	    { zz=0;
	    EALLOW;
	    GpioDataRegs.GPACLEAR.all=0x0006;//清零
	    EDIS;
	    }
    
	    else if(type==0)  //单极性
	    {count--;
	     EALLOW;
	     GpioDataRegs.GPACLEAR.all=0x0006;//gpio_2,gpio_3低电平
	     EDIS;
	     delayus(t1); 
	   
	     EALLOW;
	     GpioDataRegs.GPASET.all=0x0002;//gpio_2高电平
	     EDIS;
	  	 delayus(width);
	  	 }
	  	 
  	 	else if(type==1)  //双极性
    	{	
              //1
    	  count--;
	  	  EALLOW;
	      GpioDataRegs.GPACLEAR.all=0x0006;//gpio_2,gpio_3低电平
	      EDIS;
	      delayus((t1/2-width)); 
	         //2
	      EALLOW;
	      GpioDataRegs.GPASET.all=0x0002;//gpio_2高电平
	      EDIS;
	      delayus(width);
	        //3
	      EALLOW;
	      GpioDataRegs.GPACLEAR.all=0x0006;//gpio_2,gpio_3低电平
	      EDIS;
	      delayus((t1/2-width)); 
	     
	       //4
			  if(count!=0)  //判断的目的是为了避免输入奇数个脉冲时跳不出循环
			  {count--;   
			   EALLOW;
			   GpioDataRegs.GPASET.all=0x0004;//gpio_3高电平
			   EDIS;
			   delayus(width);
			  }
	  	 }
	
	}
}
void delayus(unsigned long m)

	{i=0;
	while(i<m) //计数没有达到的时候等待中断
	            //否则跳出循环   
	{
 	 //开中断2，M_INT2已经在头文件中定义
	IER |= M_INT2;//定时器1的周期中断int2.4;
	}
	}
interrupt void ISRTimer1(void) //定时器1周期中断服务程序
	{
	i++; //每执行一次中断计数增加一次
	PieCtrl.PIEACK.all=0x0002; //清除PIEACK中断标志位
	EvaRegs.T1CNT=0x0000; //Timer1的计数器重新赋0
	EvaRegs.EVAIFRA.all=EvaRegs.EVAIFRA.all&0x0080; 
	return;
	}

interrupt void sci_rx_isr(void)
	{
	int j;
	a=SciaRegs.SCIRXBUF.all;
	if(a=='w'||a=='W')
	{
	for(j=0;j<ss;j++)
		{buffer[j]=SciaRegs.SCIRXBUF.all;}
	width=atoi(buffer);	
	t1=1000000/freq;                 //计算周期(us)
	t=(long)(t1-width);
	}
	else if(a=='f'||a=='F')
	{
	for(j=0,h=0;j<ss;j++)
		{buffer[j]=SciaRegs.SCIRXBUF.all;}
	freq=atoi(buffer);
	t1=1000000./freq;                 //计算周期(us)
	t=(long)(t1-width);            //低电平的时间长度(us)
	}
	else if(a=='n'||a=='N')
	{
	for(j=0;j<ss;j++)
		{buffer[j]=SciaRegs.SCIRXBUF.all;}
	count=atol(buffer);	
	count1=count;
	}
	else if(a=='s')	//停止按钮
	{count=0;
	zz=0;}
	else if(a=='z')	//开始按钮
	{count=count1;
	zz=1;
	}
	else if(a=='b')	//单极性
	{type=0;}
	else if(a=='c')	//双极性
	{type=1;}
	
	SciaRegs.SCIFFRX.bit.RXOVF_CLR=1;   // Clear Overflow flag
	SciaRegs.SCIFFRX.bit.RXFFINTCLR=1;   // Clear Interrupt flag
	PieCtrl.PIEACK.all|=0x100;       // Issue PIE ack
	}
	
void sci_init(void)
{
  
   SciaRegs.SCICCR.all =0x0007;   // 1 stop bit,  No loopback
                                  // No parity,8 char bits,
                                  // async mode, idle-line protocol
   SciaRegs.SCICTL1.all =0x0003;  // enable TX, RX, internal SCICLK,
                                  // Disable RX ERR, SLEEP, TXWAKE
   SciaRegs.SCICTL2.bit.TXINTENA =1;
   SciaRegs.SCICTL2.bit.RXBKINTENA =1;
   SciaRegs.SCIHBAUD = 487>>8;
   SciaRegs.SCILBAUD = 487&0x00ff;//9600
   SciaRegs.SCICCR.bit.LOOPBKENA =0; // 自测试模式禁止
   SciaRegs.SCIFFTX.all=0xC028;//接受8个字符产生一次中断
   SciaRegs.SCIFFRX.all=0x0028;
   SciaRegs.SCIFFCT.all=0x00;
   SciaRegs.SCICTL1.all =0x0023;     // Relinquish SCI from Reset
   SciaRegs.SCIFFTX.bit.TXFIFOXRESET=1;
   SciaRegs.SCIFFRX.bit.RXFIFORESET=1;
}