timer.c

AT91所有开发板的资料 AT91所有开发板的资料

 /*******************************************************************************
 * 
 * ARM Strategic Support Group
 *
 *******************************************************************************/

/*******************************************************************************
 *
 * Module       : timer.c
 * Description  : Setups 77790 IRQ registers and serives the IRQ's (timer)
 * Status       : complete
 * Platform     : AEB-1
 * History      : 980416 ASloss
 *
 *                - added button interrupt service
 *                - added header information
 *
 * Notes        : Refer to the Sharp 77790 documentation 
 *
 *******************************************************************************/

/*******************************************************************************
 * IMPORT
 *******************************************************************************/

#include "led.h"
#include "button.h"
#include "macros.h"

/*******************************************************************************
 * MACRO'S
 *******************************************************************************/

// -- countdown ...

#define COUNTDOWN	0x00effff0	

/*****************************************************************************
 * EXTERN's
 *****************************************************************************/

// none...

/*****************************************************************************
 * GLOBALS
 *****************************************************************************/

static int led_pulse = 0;

/*****************************************************************************
 * ROUTINES
 *****************************************************************************/

/* -- timer_init ----------------------------------------------------------
 *                                                            
 * Description  : Initialises the counter timer and sets the timer divisor.      
 *
 * Parameters   : none...   
 * Return       : none...
 * Notes        : none...
 *                                                                             
 */

void timer_init (void)
{
  *TMOD		= 0;
  *INTPND 	= 0x00000000; 	// Clear pending interrupts .............
}

/* -- timer_irq ------------------------------------------------------------
 *
 * Description  : interrupt service routine for timer0 interrupt.
 *
 * Parameters   : none...
 * Return       : none...
 * Notes        : timer interrupt everytime the counter reaches 0. To reset
 *				  the timer TDATA0 has to have a new initialization value.
 *				  Finally the last act is to unmask the timer interrupt on 
 *				  the Samsung KS3250C100.
 *
 */ 

void  timer_irq (void) 
{ 

	// -- reset timer interrupt.........

	*INTPND	= 1<<10;
	*TDATA0	= COUNTDOWN; 

   // -- toggle the LED D4 to show timer interrupt...
   
   if ( led_pulse ) 
	{ LED_4_ON; led_pulse = 0; }
   else 
	{ LED_4_OFF; led_pulse = 1; }

	// -- unmask the interrupt source....
	
	*(volatile int*)INTMSK &= ~((1<<INT_GLOBAL)|(1<<10)|(1<<0));
} 



/* -- timer_start -----------------------------------------------------------
 *
 * Description  : switches the timer on
 *
 * Parameters   : none...
 * Return       : none...
 * Notes        : none...
 *
 */  

void timer_start (void)
{	
  	*TDATA0		 = COUNTDOWN;	// load Counter Timer ..............
 	*TMOD 		|= 0x1;			// enable interval interrupt .......
  
 	// -- unmask the interrupt source.... 
  	
  	*(volatile int*)INTMSK &= ~((1 << INT_GLOBAL) | (1<<10) | (1<<0));     
}

/*******************************************************************************
 * END OF irq.c
 *******************************************************************************/