main.c

用飞思卡尔芯片HCS12的PWM功能控制直流电机

#include <hidef.h>      /* common defines and macros */
#include <mc9s12dg128.h>     /* derivative information */


#pragma LINK_INFO DERIVATIVE "mc9s12dg128b"

//16-bit PWM,use 2MHz~0.5us
//Bus clock:24MHz; Prescale:12;
//Output : Channels 1
void PMW_Initial(void)
{
   
   PWME      =   PWME   & 0xFC;
   
   PWMPOL    =   PWMPOL | 0x02;  	//	Polarity:High
   PWMCTL    =   PWMCTL | 0x10;    //0 。1联级，16_bit PWM 
   PWMCLK    =   PWMCLK | 0x02;  	 //PTP1 use SA       
   

   PWMPRCLK	 =   0;                //Clock A=Bus Clock
   PWMSCLA 	 =   0x06;               //SA = Bus/(2*PWMSCLA),SA = 24M/12=2M
   
   PWMPER0   =   0x9c;					   //40000,20ms
   PWMPER1   =   0x40;
   
   PWMDTY0   =	 0x4e;			       //20000 10ms   duty
   PWMDTY1   =   0x20;
   PWME      =   PWME   | 0x02;       //start
   
   /* duty 为2816时,舵机处于中间*/
   
}


void PLL_Init(void)
 {
  REFDV=0x01; 
  SYNR=0x02;						    //Set the system clock 48MHz
}

void Start_PLL(void) {
  asm{
    BRCLR CRGFLG,#$08,*
    BSET CLKSEL,#$80
    }													  
}   
  

void main(void) {
  /* put your own code here */
  
  PLL_Init();
  Start_PLL();
  PMW_Initial();			//Period:20ms;Duty:1.5ms;
  
  EnableInterrupts;
  for(;;) {} /* wait forever */
}