text: /*
   * @brief LPC18xx/43xx specific stopwatch implementation
   *
   * @note
   * Copyright(C) NXP Semiconductors, 2014
   * All rights reserved.
   *
   * @par
   * Software that is described herein is for illustrative purposes only
   * which provides customers with programming information regarding the
   * LPC products.  This software is supplied "AS IS" without any warranties of
   * any kind, and NXP Semiconductors and its licensor disclaim any and
   * all warranties, express or implied, including all implied warranties of
   * merchantability, fitness for a particular purpose and non-infringement of
   * intellectual property rights.  NXP Semiconductors assumes no responsibility
   * or liability for the use of the software, conveys no license or rights under any
   * patent, copyright, mask work right, or any other intellectual property rights in
   * or to any products. NXP Semiconductors reserves the right to make changes
   * in the software without notification. NXP Semiconductors also makes no
   * representation or warranty that such application will be suitable for the
   * specified use without further testing or modification.
   *
   * @par
   * Permission to use, copy, modify, and distribute this software and its
   * documentation is hereby granted, under NXP Semiconductors' and its
   * licensor's relevant copyrights in the software, without fee, provided that it
   * is used in conjunction with NXP Semiconductors microcontrollers.  This
   * copyright, permission, and disclaimer notice must appear in all copies of
   * this code.
   */
  
  #include "chip.h"
  #include "stopwatch.h"
  
  /*****************************************************************************
   * Private types/enumerations/variables
   ****************************************************************************/
  
  /* Precompute these to optimize runtime */
  static uint32_t ticksPerSecond;
  static uint32_t ticksPerMs;
  static uint32_t ticksPerUs;
  
  /*****************************************************************************
   * Public types/enumerations/variables
   ****************************************************************************/
  
  /*****************************************************************************
   * Private functions
   ****************************************************************************/
  
  /*****************************************************************************
   * Public functions
   ****************************************************************************/
  
  /* Initialize stopwatch */
  void StopWatch_Init(void)
  {
     /* Use timer 1. Set prescaler to divide by 8 */
     const uint32_t prescaleDivisor = 8;
     Chip_TIMER_Init(LPC_TIMER0);
     Chip_TIMER_PrescaleSet(LPC_TIMER0, prescaleDivisor - 1);
     Chip_TIMER_Enable(LPC_TIMER0);
  
     /* Pre-compute tick rate. */
     ticksPerSecond = Chip_Clock_GetRate(CLK_MX_TIMER0) / prescaleDivisor;
     ticksPerMs = ticksPerSecond / 1000;
     ticksPerUs = ticksPerSecond / 1000000;
  }
  
  /* Start a stopwatch */
  uint32_t StopWatch_Start(void)
  {
     /* Return the current timer count. */
     return Chip_TIMER_ReadCount(LPC_TIMER0);
  }
  
  /* Returns number of ticks per second of the stopwatch timer */
  uint32_t StopWatch_TicksPerSecond(void)
  {
     return ticksPerSecond;
  }
  
  /* Converts from stopwatch ticks to mS. */
  uint32_t StopWatch_TicksToMs(uint32_t ticks)
  {
     return ticks / ticksPerMs;
  }
  
  /* Converts from stopwatch ticks to uS. */
  uint32_t StopWatch_TicksToUs(uint32_t ticks)
  {
     return ticks / ticksPerUs;
  }
  
  /* Converts from mS to stopwatch ticks. */
  uint32_t StopWatch_MsToTicks(uint32_t mS)
  {
     return mS * ticksPerMs;
  }
  
  /* Converts from uS to stopwatch ticks. */
  uint32_t StopWatch_UsToTicks(uint32_t uS)
  {
     return uS * ticksPerUs;
  }
  