adc_17xx_40xx.c

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/*
 * @brief LPC17xx/40xx ADC conversion driver
 *
 * @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 "chip.h"

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

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

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

/* Get divider value for  */
STATIC uint8_t getAdcClkDiv(uint32_t adcRate)
{
 uint32_t adcBlockFreq;
 uint32_t fullAdcRate;
 uint8_t div;

 /* The APB clock (PCLK_ADC0) is divided by (CLKDIV+1) to produce the clock for
  * A/D converter, which should be less than or equal to 12.4MHz.
  * A fully conversion requires 31 of these clocks.
  * ADC clock = PCLK_ADC0 / (CLKDIV + 1);
  * ADC rate = ADC clock / (the number of clocks required for each conversion);
  */
#if defined(CHIP_LPC175X_6X)
 adcBlockFreq = Chip_Clock_GetPeripheralClockRate(SYSCTL_PCLK_ADC);
 fullAdcRate = adcRate * 65;
#else
 adcBlockFreq = Chip_Clock_GetPeripheralClockRate();
 fullAdcRate = adcRate * 31;
#endif

 /* Get the round value by fomular: (2*A + B)/(2*B) */
 div = ((adcBlockFreq * 2 + fullAdcRate) / (fullAdcRate * 2)) - 1;
 return div;
}

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

/* Shutdown ADC */
void Chip_ADC_DeInit(LPC_ADC_T *pADC)
{
 IP_ADC_DeInit(pADC);
 Chip_Clock_DisablePeriphClock(SYSCTL_CLOCK_ADC);
}

/* Initialize the ADC peripheral and the ADC setup structure to default value */
void Chip_ADC_Init(LPC_ADC_T *pADC, ADC_Clock_Setup_T *ADCSetup)
{
 uint8_t div;
 /* Enable ADC clocking and get ADC clock rate */
 Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_ADC);

 ADCSetup->adcRate = ADC_MAX_SAMPLE_RATE;
 ADCSetup->burstMode = false;
 div = getAdcClkDiv(ADC_MAX_SAMPLE_RATE);
 IP_ADC_Init(pADC, div, 0, ADC_CR_PDN);
}

/* Select the mode starting the AD conversion */
void Chip_ADC_Set_StartMode(LPC_ADC_T *pADC, CHIP_ADC_START_MODE_T mode, CHIP_ADC_EDGE_CFG_T EdgeOption)
{
 if ((mode != ADC_START_NOW) && (mode != ADC_NO_START)) {
  IP_ADC_EdgeStartConfig(pADC, (uint8_t) EdgeOption);
 }
 IP_ADC_SetStartMode(pADC, (uint8_t) mode);
}

/* Set the ADC Sample rate */
void Chip_ADC_Set_SampleRate(LPC_ADC_T *pADC, ADC_Clock_Setup_T *ADCSetup, uint32_t rate)
{
 uint8_t div;
 ADCSetup->adcRate = rate;
 div = getAdcClkDiv(rate);
 IP_ADC_Init(pADC, div, 0, ADC_CR_PDN);

}

/* Enable or disable the ADC channel on ADC peripheral */
void Chip_ADC_Channel_Enable_Cmd(LPC_ADC_T *pADC, CHIP_ADC_CHANNEL_T channel, FunctionalState NewState)
{
 IP_ADC_SetChannelNumber(pADC, channel, NewState);
}

/* Enable burst mode */
void Chip_ADC_Burst_Cmd(LPC_ADC_T *pADC, FunctionalState NewState)
{
 IP_ADC_SetStartMode(pADC, ADC_NO_START);
 IP_ADC_SetBurstMode(pADC, NewState);
}

/* Read the ADC value and convert it to 8bits value */
Status Chip_ADC_Read_Byte(LPC_ADC_T *pADC, CHIP_ADC_CHANNEL_T channel, uint8_t *data)
{
 uint16_t temp;
 Status rt;

 rt = IP_ADC_Get_Val(pADC, channel, &temp);
 *data = (uint8_t) temp;

 return rt;
}