298 lines
8.6 KiB
C
298 lines
8.6 KiB
C
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/***************************************************************************//**
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* @file
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* @brief DAC device driver for EFM32
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*
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* @author Energy Micro AS
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* @version 1.3.0
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*******************************************************************************
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* @section License
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* <b>(C) Copyright 2010 Energy Micro AS, http://www.energymicro.com</b>
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*******************************************************************************
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*
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* This source code is the property of Energy Micro AS. The source and compiled
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* code may only be used on Energy Micro "EFM32" microcontrollers.
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*
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* This copyright notice may not be removed from the source code nor changed.
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*
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* DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Energy Micro AS has no
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* obligation to support this Software. Energy Micro AS is providing the
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* Software "AS IS", with no express or implied warranties of any kind,
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* including, but not limited to, any implied warranties of merchantability
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* or fitness for any particular purpose or warranties against infringement
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* of any proprietary rights of a third party.
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*
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* Energy Micro AS will not be liable for any consequential, incidental, or
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* special damages, or any other relief, or for any claim by any third party,
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* arising from your use of this Software.
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*
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******************************************************************************/
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#include "efm32_dac.h"
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#include "efm32_cmu.h"
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#include "efm32_assert.h"
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#include "efm32_bitband.h"
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/***************************************************************************//**
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* @addtogroup EFM32_Library
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* @{
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******************************************************************************/
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/***************************************************************************//**
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* @addtogroup DAC
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* @brief EFM32 digital to analog converter utilities.
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* @{
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******************************************************************************/
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/*******************************************************************************
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******************************* DEFINES ***********************************
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******************************************************************************/
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/** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
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/** Validation of DAC register block pointer reference for assert statements. */
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#define DAC_REF_VALID(ref) ((ref) == DAC0)
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/** Validation of DAC channel for assert statements. */
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#define DAC_CH_VALID(ch) ((ch) <= 1)
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/** Max DAC clock */
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#define DAC_MAX_CLOCK 1000000
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/** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
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/*******************************************************************************
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************************** GLOBAL FUNCTIONS *******************************
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******************************************************************************/
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/***************************************************************************//**
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* @brief
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* Enable/disable DAC channel.
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*
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* @param[in] dac
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* Pointer to DAC peripheral register block.
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*
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* @param[in] ch
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* Channel to enable/disable.
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*
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* @param[in] enable
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* true to enable DAC channel, false to disable.
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******************************************************************************/
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void DAC_Enable(DAC_TypeDef *dac, unsigned int ch, bool enable)
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{
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volatile uint32_t *reg;
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EFM_ASSERT(DAC_REF_VALID(dac));
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EFM_ASSERT(DAC_CH_VALID(ch));
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if (!ch)
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{
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reg = &(dac->CH0CTRL);
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}
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else
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{
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reg = &(dac->CH1CTRL);
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}
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BITBAND_Peripheral(reg, _DAC_CH0CTRL_EN_SHIFT, (unsigned int) enable);
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}
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/***************************************************************************//**
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* @brief
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* Initialize DAC.
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*
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* @details
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* Initializes common parts for both channels. In addition, channel control
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* configuration must be done, please refer to DAC_InitChannel().
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*
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* @note
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* This function will disable both channels prior to configuration.
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*
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* @param[in] dac
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* Pointer to DAC peripheral register block.
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*
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* @param[in] init
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* Pointer to DAC initialization structure.
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******************************************************************************/
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void DAC_Init(DAC_TypeDef *dac, const DAC_Init_TypeDef *init)
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{
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uint32_t tmp;
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EFM_ASSERT(DAC_REF_VALID(dac));
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/* Make sure both channels are disabled. */
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BITBAND_Peripheral(&(dac->CH0CTRL), _DAC_CH0CTRL_EN_SHIFT, 0);
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BITBAND_Peripheral(&(dac->CH1CTRL), _DAC_CH0CTRL_EN_SHIFT, 0);
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/* Load proper calibration data depending on selected reference */
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switch (init->reference)
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{
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case dacRef2V5:
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dac->CAL = DEVINFO->DAC0CAL1;
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break;
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case dacRefVDD:
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dac->CAL = DEVINFO->DAC0CAL2;
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break;
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default: /* 1.25V */
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dac->CAL = DEVINFO->DAC0CAL0;
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break;
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}
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tmp = ((uint32_t)(init->refresh) << _DAC_CTRL_REFRSEL_SHIFT) |
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(((uint32_t)(init->prescale) << _DAC_CTRL_PRESC_SHIFT) & _DAC_CTRL_PRESC_MASK) |
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((uint32_t)(init->lpFreq) << _DAC_CTRL_LPFFREQ_SHIFT) |
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((uint32_t)(init->reference) << _DAC_CTRL_REFSEL_SHIFT) |
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((uint32_t)(init->outMode) << _DAC_CTRL_OUTMODE_SHIFT) |
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((uint32_t)(init->convMode) << _DAC_CTRL_CONVMODE_SHIFT);
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if (init->lpEnable)
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{
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tmp |= DAC_CTRL_LPFEN;
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}
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if (init->ch0ResetPre)
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{
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tmp |= DAC_CTRL_CH0PRESCRST;
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}
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if (init->outEnablePRS)
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{
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tmp |= DAC_CTRL_OUTENPRS;
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}
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if (init->sineEnable)
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{
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tmp |= DAC_CTRL_SINEMODE;
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}
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if (init->diff)
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{
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tmp |= DAC_CTRL_DIFF;
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}
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dac->CTRL = tmp;
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}
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/***************************************************************************//**
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* @brief
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* Initialize DAC channel.
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*
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* @param[in] dac
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* Pointer to DAC peripheral register block.
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*
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* @param[in] init
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* Pointer to DAC initialization structure.
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*
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* @param[in] ch
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* Channel number to initialize.
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******************************************************************************/
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void DAC_InitChannel(DAC_TypeDef *dac,
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const DAC_InitChannel_TypeDef *init,
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unsigned int ch)
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{
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uint32_t tmp;
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EFM_ASSERT(DAC_REF_VALID(dac));
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EFM_ASSERT(DAC_CH_VALID(ch));
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tmp = (uint32_t)(init->prsSel) << _DAC_CH0CTRL_PRSSEL_SHIFT;
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if (init->enable)
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{
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tmp |= DAC_CH0CTRL_EN;
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}
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if (init->prsEnable)
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{
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tmp |= DAC_CH0CTRL_PRSEN;
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}
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if (init->refreshEnable)
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{
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tmp |= DAC_CH0CTRL_REFREN;
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}
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if (ch)
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{
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dac->CH1CTRL = tmp;
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}
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else
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{
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dac->CH0CTRL = tmp;
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}
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}
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/***************************************************************************//**
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* @brief
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* Calculate prescaler value used to determine DAC clock.
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*
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* @details
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* The DAC clock is given by: HFPERCLK / (prescale ^ 2).
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*
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* @param[in] dacFreq DAC frequency wanted. The frequency will automatically
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* be adjusted to be below max allowed DAC clock.
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*
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* @param[in] hfperFreq Frequency in Hz of reference HFPER clock. Set to 0 to
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* use currently defined HFPER clock setting.
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*
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* @return
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* Prescaler value to use for DAC in order to achieve a clock value
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* <= @p dacFreq.
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******************************************************************************/
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uint8_t DAC_PrescaleCalc(uint32_t dacFreq, uint32_t hfperFreq)
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{
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uint32_t ret;
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/* Make sure selected DAC clock is below max value */
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if (dacFreq > DAC_MAX_CLOCK)
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{
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dacFreq = DAC_MAX_CLOCK;
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}
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/* Use current HFPER frequency? */
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if (!hfperFreq)
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{
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hfperFreq = CMU_ClockFreqGet(cmuClock_HFPER);
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}
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/* Iterate in order to determine best prescale value. Only a few possible */
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/* values. We start with lowest prescaler value in order to get first */
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/* equal or below wanted DAC frequency value. */
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for (ret = 0; ret <= (_DAC_CTRL_PRESC_MASK >> _DAC_CTRL_PRESC_SHIFT); ret++)
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{
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if ((hfperFreq >> ret) <= dacFreq)
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break;
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}
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return((uint8_t) ret);
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}
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/***************************************************************************//**
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* @brief
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* Reset DAC to same state as after a HW reset.
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*
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* @param[in] dac
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* Pointer to ADC peripheral register block.
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******************************************************************************/
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void DAC_Reset(DAC_TypeDef *dac)
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{
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/* Disable channels, before resetting other registers. */
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dac->CH0CTRL = _DAC_CH0CTRL_RESETVALUE;
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dac->CH1CTRL = _DAC_CH1CTRL_RESETVALUE;
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dac->CTRL = _DAC_CTRL_RESETVALUE;
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dac->IEN = _DAC_IEN_RESETVALUE;
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dac->IFC = _DAC_IFC_MASK;
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dac->CAL = DEVINFO->DAC0CAL0;
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dac->BIASPROG = _DAC_BIASPROG_RESETVALUE;
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/* Do not reset route register, setting should be done independently */
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}
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/** @} (end addtogroup DAC) */
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/** @} (end addtogroup EFM32_Library) */
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