target.h

PWM Generation Using HCS12 Timer Channels

/******************************************************************************
*                                             COPYRIGHT (c) MOTOROLA 2000   
* FILE NAME: target.h     REVISION 1.1                                        
*                                                                           
* PURPOSE: header file for EVB program  							 
*                                                                           
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*******************************************************************************  
**  THIS CODE IS ONLY INTENDED AS AN EXAMPLE FOR THE METROWERKS COMPILER AND **  
**      THE STAR12 EVB AND HAS ONLY BEEN GIVEN A MIMIMUM LEVEL OF TEST.      **  
**  IT IS PROVIDED 'AS SEEN' WITH NO GUARANTEES AND NO PROMISE OF SUPPORT.   **  
*******************************************************************************  
*******************************************************************************
*                                                                           
*                                                                           
* DESCRIPTION:  definitions for target specifics such as clock speed        
*                                                                           
* NOTE: Modify this file depending on the crystal frequency of the target   
*                                                                           
* AUTHOR: Martyn Gallop        LOCATION: EKB      LAST EDIT DATE: 30.07.01  
*                                                                           
* UPDATE HISTORY                                                            
* REV      	AUTHOR      DATE       	DESCRIPTION OF CHANGE                    
* ---      	------      ---------   ---------------------                    
* 1.0      	M.Gallop    03/06/01	                                         
* 1.1		M.Gallop    30/07/01    - Added KHz version of XTAL_FREQ
*									- Reformated file info section
* 1.2		M.Gallop	09/10/01	- added equations from xtal.h           
*                                                                           
******************************************************************************/

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#define XTAL_FREQ		16.0 	/* MHz */
#define XTAL_FREQ_KHZ	16000.0	/* KHz */

#define XTAL_BUS_FREQ_KHZ     XTAL_FREQ_KHZ / 2.0

#define XTAL_CPU_PERIOD_US   1000.0 / XTAL_BUS_FREQ  /* in microseconds */

#define XTAL_TIMER_PRESCALER_BITS    0  /* value 0-7; prescaler = 2^^n */

#define XTAL_MS_COUNT	(tU16)(XTAL_BUS_FREQ_KHZ / (1 << XTAL_TIMER_PRESCALER_BITS))