pwm.dsp

非常实用的AD和pwm的ad公司21990dsp芯片的控制源代码

/****************************************************************************************
*										       *
*  Library: Configuration of PWM block 	for single update mode					       *

* File: pwm.dsp								       *
*										       *
* Description:  pwm code file						       *
* Purpose    : Library routines for PWM block operation									       *
* 										       *
* Author     : JC								       *
* Version    : 1.0								       *
* Date       : Dec 2001                                                            *
* Modification History:    none							       *
*										       *
* Embedded Control Systems							       *
* Analog Devices Inc.								       *
****************************************************************************************/

#include <main.h>;

/***************************************************************************************
* Calculate Configuration Register Contents from Parameters                            *
***************************************************************************************/

#define PWM_Period      	 H_clock * 1000 / 2 /PWM_freq		
#define PWM_DeadTime     	 Deadtime * H_clock / 1000 / 2 / 1000		
#define PWM_syncwidth		 PWM_syncpulse*H_clock/1000/1000-1   	

/***************************************************************************************
* Constants Defined in the Module                                                      *
***************************************************************************************/

/*none*/

/***************************************************************************************
* Routines Defined in this Module                                                      *
***************************************************************************************/

.global  PWM_Init_;

/***************************************************************************************
* Global Variables Defined in this Module                                              *
***************************************************************************************/

/* None */

/***************************************************************************************
* Local Variables Defined in this Module                                               *
***************************************************************************************/

/* None*/ 

/***************************************************************************************
*                                                                                      *
* Type: Routine                                                       		       *
*                                                                                      *
* Call: call PWM_Init_;                                                                *
*                                                                                      *
* Initialises the PWM block and produces 50% dutycycle PWM outputs                     *
*                                                                                      *
* Inputs  :   	Configuration Constants                                                *
*                                                                                      *
* Ouputs  :	None                                                                   *
*                                                                                      *
* Modified:	     AR                                                  *
*                                                                                      *
***************************************************************************************/
.section/pm seg_pmcode;

PWM_Init_:				// Initialise PWM block 

	IOPG=PWM0_Page;   	// page of PWM0 block
	ar = PWM_Period;
	IO(PWM0_TM)= ar;	//write to PWM period register
	ar =PWM_DeadTime;
	IO(PWM0_DT)= ar;	//write to PWM deadtime register
	ar =PWM_syncwidth;
	IO(PWM0_SYNCWT)= ar;//write to PWMSYNC width register
	ar = 0;				//50% duty cycle
	IO(PWM0_CHA)= ar;	//Write duty cycle to Channel A
	IO(PWM0_CHB)= ar;	//Write duty cycle to Channel B
	IO(PWM0_CHC)= ar;	//Write duty cycle to Channel C

	ar= 0x0003;
	IO(PWM0_CTRL)=ar;	// enable PWM block, SYNC will be generated after a TRIP
	rts;