/***************************************************************************//**
 *   @file   TIME.c
 *   @brief  Implementation of TIME Driver for RENESAS RL78G14 Processor.
 *   @author Dan Nechita
********************************************************************************
 * Copyright 2012(c) Analog Devices, Inc.
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  - Neither the name of Analog Devices, Inc. nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *  - The use of this software may or may not infringe the patent rights
 *    of one or more patent holders.  This license does not release you
 *    from the requirement that you obtain separate licenses from these
 *    patent holders to use this software.
 *  - Use of the software either in source or binary form, must be run
 *    on or directly connected to an Analog Devices Inc. component.
 *
 * THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT,
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
********************************************************************************
 *   SVN Revision: $WCREV$
*******************************************************************************/

/******************************************************************************/
/***************************** Include Files **********************************/
/******************************************************************************/
#include "RDKRL78G14.h"    // RDKRL78G14 definitions.
#include "TIME.h"          // TIME definitions.

/*****************************************************************************/
/************************** Macros Definitions *******************************/
/*****************************************************************************/
#define TIMER_CNT_INTERVAL      65536

/*****************************************************************************/
/************************ Variables Declarations *****************************/
/*****************************************************************************/
unsigned short overflowCounter = 0;

/******************************************************************************/
/************************ Functions Definitions *******************************/
/******************************************************************************/

/***************************************************************************//**
 * @brief INTTM00 interrupt service routine.
 *
 * @return None.
*******************************************************************************/
#pragma vector = INTTM00_vect
__interrupt static void Timer0InterruptHandler(void)
{
    overflowCounter++;
}

/***************************************************************************//**
 * @brief Initializes the timer used in this driver.
 *
 * @return status - Result of the initialization procedure.
 *                  Example:  0 - if initialization was successful;
 *                           -1 - if initialization was unsuccessful.
*******************************************************************************/
char TIME_Init(void)
{
    PER0   |= 0x0001;   // Enable Supply for Unit 0 that contains timers 0..7.
    TT0    |= 0x0001;   // Stop channel 0(Timer 0).
    TPS0    = 0x0005;   // CK00 = FCLK / 32.
    TMR00  |= 0x0000;   // CK00 input clock for channel 0.
    TMMK00  = 1;        // Disable INTTM00 interrupt.
    TMIF00  = 0;        // Clear INTM00 interrupt flag.
    /* Set INTTM00 low priority */
    TMPR100 = 1;
    TMPR000 = 1;
    /* Configure channel 0 as a interval timer. */
    TMR00  |= 0x0000;   // Interval timer mode.
    TO0    &= ~0x0001;  // Timer 0 output value is "0".
    TOE0   &= ~0x0001;  // Disable output of timer 0.
    TMMK00  = 0;        // Enable INTTM00 interrupt.
    
    return 0;
}

/***************************************************************************//**
 * @brief The timer begins to count in steps of microseconds(us) until the user
 *        calls a stop measurement function.
 *
 * @return None.
*******************************************************************************/
void TIME_StartMeasure(void)
{
    TDR00  = 0xFFFF;
    overflowCounter = 0;
    TS0   |= 0x0001;    // Start timer 0.
    TMIF00 = 0;         // Clear INTM00 interrupt flag.
}

/***************************************************************************//**
 * @brief Stops the measurement process when the functions is called.
 *
 * @return Time(in microseconds) elapsed since the measurement began.
*******************************************************************************/
unsigned long TIME_StopMeasure(void)
{
    unsigned long  elapsedUs = 0;
    unsigned short timerCnt  = 0;
    
    timerCnt  = TCR00;
    TT0      |= 0x0001;   // Stop Timer 0.
    TMIF00    = 0;        // Clear INTM00 interrupt flag.
    overflowCounter = 0;
    elapsedUs =  ((unsigned long)overflowCounter * TIMER_CNT_INTERVAL) + 
             (0xFFFF - timerCnt);
    
    return elapsedUs;
}

/***************************************************************************//**
 * @brief Creates a delay of microseconds.
 *
 * @return None.
*******************************************************************************/
void TIME_DelayUs(unsigned short usUnits)
{
    TDR00 = usUnits;
    TS0  |= 0x0001; // Start timer 0.
    while(!overflowCounter)
    {
        ;
    }
    overflowCounter = 0;
    TT0  |= 0x0001; // Stop Timer 0.
}

/***************************************************************************//**
 * @brief Creates a delay of milliseconds.
 *
 * @return None.
*******************************************************************************/
void TIME_DelayMs(unsigned short msUnits)
{
    TDR00 = 0x3E7;  // 0x3E7 = 999(decimal). Timer will count down to 0.
    TS0  |= 0x0001; // Start timer 0.
    while(overflowCounter < msUnits)
    {
        ;
    }
    overflowCounter = 0;
    TT0  |= 0x0001; // Stop Timer 0.   
}