nes-proj/TIME.c

/***************************************************************************//**
 *   @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. */
}