acmp.c

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/*
 * @brief Analog Comparator example.
 *
 * @note
 * Copyright(C) NXP Semiconductors, 2012
 * 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 "board.h"

/*****************************************************************************
 * Private types/enumerations/variables
 ****************************************************************************/

/*****************************************************************************
 * Public types/enumerations/variables
 ****************************************************************************/

/*****************************************************************************
 * Private functions
 ****************************************************************************/

/*****************************************************************************
 * Public functions
 ****************************************************************************/

void CMP_IRQHandler(void)
{
 /* Clear the interrupt */
 Chip_ACMP_EdgeClear(LPC_CMP);

 __SEV();
}

void HW_Setup(void)
{
 /* initialize the board */
 Board_Init();

 /* initialize the ACMP */
 Chip_ACMP_Init(LPC_CMP);

 /* Enable the clock to the Switch Matrix */
 Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_SWM);

 /* Configure the SWM for ACMP_I1 as the input for the Analog Comparator. */
 Chip_SWM_FixedPinEnable(ACMP_I1, ENABLE);

 /* Set the LPC8XX_ACMP_O_PINx (in sys_config.h) pin direction as an output. */
 Chip_GPIO_SetDir(LPC_GPIO_PORT, 0, LPC8XX_ACMP_O_PINx, 1);

 /* Configure the SWM for PIO15 as the output for the comparator. */
 Chip_SWM_MovablePinAssign(SWM_ACMP_O_O, PIO15);

 /* Positive and negative references, both edges, no hysteresis */
 Chip_ACMP_SetupAMCPRefs(LPC_CMP, ACMP_EDGESEL_BOTH, ACMP_POSIN_ACMP_I1, ACMP_NEGIN_INT_REF, ACMP_HYS_NONE);

 /* Disable the clock to the Switch Matrix to save power */
 Chip_Clock_DisablePeriphClock(SYSCTL_CLOCK_SWM);

 /* Enable the Interrupt for the compare output */
 NVIC_EnableIRQ(CMP_IRQn);
}

int main(void)
{
 /* Board and hardware setup */
 HW_Setup();

 while (1) {
  /* Enter low power mode until interrupt */
  __WFE();

  if (Chip_ACMP_GetCompStatus(LPC_CMP) & ACMP_COMPSTAT_BIT) {
   Board_LED_Set(0, false);
  }
  else {
   Board_LED_Set(0, true);
  }
 }

 return 0;
}