pwm.c

网络上流行的44b0开发板比较全面的测试代码

#include <string.h>
#include "..\inc\44b.h"
#include "..\inc\44blib.h"
#include "..\inc\timer.h"

#define READ_COUNT2 (rTCNTO2 & 0xffff)
#define MaxBeepFreq	20000
#define MinBeepFreq	20

extern int  Uart_GetIntNum(void);
void SetBeepPwm(unsigned short Freq, unsigned char HiRatio);
void StopBeepPwm(void);
void __irq TIMER2_int(void);
 //volatile int isWdtInt;
unsigned int pwmcnt=0;

/****************************************
 *	PWM (BEEP) test		*
 ****************************************/
void Test_Pwm(void)
{
  int nFeq, nRatio;

  sysUtilsLightLed (LED_ALL, FALSE);
  
  Uart_Printf ("PWM Test,We use Timer2 to implement PWM.\n");
  for (;;)
  {
    Uart_Printf("Please Input the Frequency F= (%d--%d): ", MinBeepFreq,MaxBeepFreq);
    nFeq = Uart_GetIntNum1 ();
    if (nFeq != 0)
    {
      if ((nFeq < MinBeepFreq) || (nFeq > MaxBeepFreq))
      {
        continue;
      }
      break;
    }
    Uart_Printf("Error Input, Please input it again.\n");
  }

  for (;;)
  {
    Uart_Printf("Please Input the ratio R= (1--99):"); 
    nRatio = Uart_GetIntNum1 ();
    if (nRatio != 0)
    {
      if ((nRatio < 1) || (nRatio > 99))
      {
        continue;
      }
      break;
    }
    Uart_Printf("Error Input, Please input it again.\n");
  }

  Uart_Printf("Feq=%d. Ratio=%d.\n", nFeq, nRatio);
  
  rINTCON = 5;    //irq enable, non vector mode
  rINTMOD = 0;   //All irq mode
  rINTMSK =~(BIT_GLOBAL|BIT_TIMER2);//enable timer2 interrupt
  pISR_TIMER2 = (unsigned  int)TIMER2_int;   //(unsigned)

  rPDATE = 0x157;			//Beep = 10
  rPCONE = 0x596b;      // tout2				
  rPUPE  = 0xff;

  SetBeepPwm (nFeq, nRatio);

  while (Uart_GetKey () == 0);
  
  StopBeepPwm();
}

void SetBeepPwm(unsigned short Freq, unsigned char HiRatio)
{
  if(Freq>MaxBeepFreq)
  {
    Freq = MaxBeepFreq;
  }
  
  if(HiRatio>100)
  {
    HiRatio = 100;
  }
  
  rTCON  	&= 0xffff0fff;					// clear manual update bit, stop Timer2
  rTCFG0 	&= 0xffff00ff;					// set Timer 2&3 prescaler 0
  rTCFG1 	&= 0xfffff0ff;					// set Timer 2 MUX 1/16
  rTCFG1  |= 0x00000300;	

  rTCNTB2 = MCLK/(Freq*16);				//if set inverter off, when TCNT2<=TCMP2, TOUT is high, TCNT2>TCMP2, TOUT is low
  rTCMPB2 = (rTCNTB2*(100-HiRatio))/100;	//if set inverter on,  when TCNT2<=TCMP2, TOUT is low,  TCNT2>TCMP2, TOUT is high
  rTCON	|= 0x00002000;					  // manual update
  rTCON	&= 0xffff0fff;	  				  // clear manal update bit
  rTCON   |= 0x0000d000;					  // auto reload, inverter on, start Timer 2
}

void StopBeepPwm(void)
{
  rTCON &= ~0x1000;
  rINTMSK |= (BIT_GLOBAL|BIT_TIMER2);
}

void __irq TIMER2_int(void)
{
  rI_ISPC=BIT_TIMER2;
  pwmcnt++;
  return ;
}