timer.c

ST公司的upsd34XX评估板固定源程序

/*------------------------------------------------------------------------------
TIMER.C:  Timer tick routines.

Copyright 1995-1996 Keil Software, Inc.
------------------------------------------------------------------------------*/

#include "upsd_cfg.h"

#include "upsd.h"				// SFRs
#include "upsd_xreg.h"			// extended registers in uPSD

#include "timer_func.h"

/*------------------------------------------------------------------------------
		 Local Macro and Manifest Constant Declarations
------------------------------------------------------------------------------*/
#define INT_DISABLE	EA = 0
#define INT_ENABLE	EA = 1

#define TIMER0_COUNT	(0-((OSC/(12*TIMER0_PERIOD))-17))
//#define TIMER0_COUNT	 0xdb62     /* 10000h - ((16 Mhz / (12 * FREQ)) - 17)  */
                                    /*  16Mhz = 0xcbfc           100hz        */
			            			/*  12mHZ = 0xd8ff                        */
				    				/*  11.059Mhz =  0xdb62      */
									/*   6Mhz = 0xec89    */

/*------------------------------------------------------------------------------
			  Local Variable Declarations
------------------------------------------------------------------------------*/

static idata unsigned int timer0_tick;

/*------------------------------------------------------------------------------
static void timer0_isr (void);

This function is an interrupt service routine for TIMER 0.  It should never
be called by a C or assembly function.  It will be executed automatically
when TIMER 0 overflows.
------------------------------------------------------------------------------*/
static void timer0_isr (void) interrupt TF0_VECTOR using 1
{

/*------------------------------------------------
Adjust the timer 0 counter so that we get another 
interrupt in 10ms.
------------------------------------------------*/
	TR0 = 0;				/* stop timer 0 */

	TL0 = TL0 + (TIMER0_COUNT & 0x00FF);
	TH0 = TH0 + (TIMER0_COUNT >> 8);

	TR0 = 1;				/* start timer 0 */

/*------------------------------------------------
Increment the timer tick.  This interrupt should
occur approximately every 10ms. So, the resulotion
of the timer will be 100Hz not including interrupt
latency.
------------------------------------------------*/
	timer0_tick++;

	do_timer0();
}

/*------------------------------------------------------------------------------
This function enables TIMER 0.  TIMER 0 will generate a synchronous interrupt
once every 1kHz.
------------------------------------------------------------------------------*/
void timer0_initialize (void)
{
	INT_DISABLE;			/* disable interrupts */

	timer0_tick = 0;

	TR0 = 0;				/* stop timer 0 */

	TMOD &= ~0x0F;			/* clear timer 0 mode bits */
	TMOD |= 0x01;			/* put timer 0 into 16-bit no prescale */

	TL0 = (TIMER0_COUNT & 0x00FF);
	TH0 = (TIMER0_COUNT >> 8);

	PT0 = 0;			/* set low priority for timer 0 */
	ET0 = 1;			/* enable timer 0 interrupt */

	TR0 = 1;			/* start timer 0 */

	INT_ENABLE;			/* enable interrupts */
}

/*------------------------------------------------------------------------------
This function returns the current timer0 tick count.
------------------------------------------------------------------------------*/
unsigned int timer0_count (void)
{
unsigned int t;

	INT_DISABLE;
	t = timer0_tick;
	INT_ENABLE;

return (t);
}

/*------------------------------------------------------------------------------
This function returns the number of timer ticks that have elapsed since the
specified count.
------------------------------------------------------------------------------*/
unsigned int timer0_elapsed_count (unsigned int count)
{
return (timer0_count () - count);
}

/*------------------------------------------------------------------------------
This function waits for 'count' timer ticks to pass.
------------------------------------------------------------------------------*/
void timer0_wait (unsigned int count)
{
unsigned int start_count;

	start_count = timer0_count ();

	while (timer0_elapsed_count (start_count) <= count)
	{
	//
	}
}

/*------------------------------------------------------------------------------
------------------------------------------------------------------------------*/