timer.c

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/*****************************************************************************
 *   timer.c:  Timer C file for Philips LPC214x Family Microprocessors
 *
 *   Copyright(C) 2006, Philips Semiconductor
 *   All rights reserved.
 *
 *   History
 *   2005.10.01  ver 1.00    Prelimnary version, first Release
 *
******************************************************************************/
#include "LPC214x.h"            /* LPC21XX Peripheral Registers */
#include "type.h"
#include "irq.h"
#include "timer.h"

#include "interrupt_utils.h"

volatile DWORD timer_counter = 0;

/******************************************************************************
** Function name:               Timer0Handler
**
** Descriptions:                Timer/Counter 0 interrupt handler
**                              executes each 10ms @ 60 MHz CPU Clock
**
** parameters:                  None
** Returned value:              None
** 
******************************************************************************/
// mthomas: static inserted to avoid warning by gcc 4.1.0
#if 1
static void /*RAMFUNC*/ Timer0Handler (void) __irq
{  
    T0IR = 1;                   /* clear interrupt flag */
    IENABLE;                    /* handles nested interrupt */

    timer_counter++;

    IDISABLE;
    VICVectAddr = 0;            /* Acknowledge Interrupt */
}
#endif

#if 0
// mthomas: macro-approach - not needed since there
// is an assembler-wrapper provided in Startup.S
static void NACKEDFUNC Timer0Handler (void) __irq
{  
        ISR_STORE();
    T0IR = 1;                   /* clear interrupt flag */
        ISR_ENABLE_NEST();  /* handles nested interrupt */

    timer_counter++;

        ISR_DISABLE_NEST();     /* Disable Interrupt nesting */
    VICVectAddr = 0;            /* Acknowledge Interrupt */
        ISR_RESTORE();
}
#endif

/******************************************************************************
** Function name:               enable_timer
**
** Descriptions:                Enable timer
**
** parameters:                  timer number: 0 or 1
** Returned value:              None
** 
******************************************************************************/
void enable_timer( BYTE timer_num )
{
    if ( timer_num == 0 )
    {
        T0TCR = 1;
    }
    else
    {
        T1TCR = 1;
    }
    return;
}

/******************************************************************************
** Function name:               disable_timer
**
** Descriptions:                Disable timer
**
** parameters:                  timer number: 0 or 1
** Returned value:              None
** 
******************************************************************************/
void disable_timer( BYTE timer_num )
{
    if ( timer_num == 0 )
    {
        T0TCR = 0;
    }
    else
    {
        T1TCR = 0;
    }
    return;
}

/******************************************************************************
** Function name:               reset_timer
**
** Descriptions:                Reset timer
**
** parameters:                  timer number: 0 or 1
** Returned value:              None
** 
******************************************************************************/
void reset_timer( BYTE timer_num )
{
    DWORD regVal;

    if ( timer_num == 0 )
    {
        regVal = T0TCR;
        regVal |= 0x02;
        T0TCR = regVal;
    }
    else
    {
        regVal = T1TCR;
        regVal |= 0x02;
        T1TCR = regVal;
    }
    return;
}

/******************************************************************************
** Function name:               init_timer
**
** Descriptions:                Initialize timer, set timer interval, reset timer,
**                              install timer interrupt handler
**
** parameters:                  None
** Returned value:              true or false, if the interrupt handler can't be
**                              installed, return false.
** 
******************************************************************************/
DWORD init_timer (void) 
{
    timer_counter = 0;
    T0MR0 = INTERVAL_10MS;      /* 10mSec = 150.000-1 counts */
    T0MCR = 3;                  /* Interrupt and Reset on MR0 */
    if ( install_irq( TIMER0_INT, (void *)Timer0Handler ) == FALSE )
    {
        return (FALSE);
    }
    else
    {
        return (TRUE);
    }
}