292 lines
8.6 KiB
C
292 lines
8.6 KiB
C
/***************************************************************************//**
|
|
* @file
|
|
* @brief Digital to Analog Coversion (DAC) Peripheral API
|
|
* @author Energy Micro AS
|
|
* @version 3.0.0
|
|
*******************************************************************************
|
|
* @section License
|
|
* <b>(C) Copyright 2012 Energy Micro AS, http://www.energymicro.com</b>
|
|
*******************************************************************************
|
|
*
|
|
* Permission is granted to anyone to use this software for any purpose,
|
|
* including commercial applications, and to alter it and redistribute it
|
|
* freely, subject to the following restrictions:
|
|
*
|
|
* 1. The origin of this software must not be misrepresented; you must not
|
|
* claim that you wrote the original software.
|
|
* 2. Altered source versions must be plainly marked as such, and must not be
|
|
* misrepresented as being the original software.
|
|
* 3. This notice may not be removed or altered from any source distribution.
|
|
*
|
|
* DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Energy Micro AS has no
|
|
* obligation to support this Software. Energy Micro AS is providing the
|
|
* Software "AS IS", with no express or implied warranties of any kind,
|
|
* including, but not limited to, any implied warranties of merchantability
|
|
* or fitness for any particular purpose or warranties against infringement
|
|
* of any proprietary rights of a third party.
|
|
*
|
|
* Energy Micro AS will not be liable for any consequential, incidental, or
|
|
* special damages, or any other relief, or for any claim by any third party,
|
|
* arising from your use of this Software.
|
|
*
|
|
******************************************************************************/
|
|
#include "em_dac.h"
|
|
#include "em_cmu.h"
|
|
#include "em_assert.h"
|
|
#include "em_bitband.h"
|
|
|
|
/***************************************************************************//**
|
|
* @addtogroup EM_Library
|
|
* @{
|
|
******************************************************************************/
|
|
|
|
/***************************************************************************//**
|
|
* @addtogroup DAC
|
|
* @brief Digital to Analog Coversion (DAC) Peripheral API
|
|
* @{
|
|
******************************************************************************/
|
|
|
|
/*******************************************************************************
|
|
******************************* DEFINES ***********************************
|
|
******************************************************************************/
|
|
|
|
/** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
|
|
|
|
/** Validation of DAC channel for assert statements. */
|
|
#define DAC_CH_VALID(ch) ((ch) <= 1)
|
|
|
|
/** Max DAC clock */
|
|
#define DAC_MAX_CLOCK 1000000
|
|
|
|
/** @endcond */
|
|
|
|
/*******************************************************************************
|
|
************************** GLOBAL FUNCTIONS *******************************
|
|
******************************************************************************/
|
|
|
|
/***************************************************************************//**
|
|
* @brief
|
|
* Enable/disable DAC channel.
|
|
*
|
|
* @param[in] dac
|
|
* Pointer to DAC peripheral register block.
|
|
*
|
|
* @param[in] ch
|
|
* Channel to enable/disable.
|
|
*
|
|
* @param[in] enable
|
|
* true to enable DAC channel, false to disable.
|
|
******************************************************************************/
|
|
void DAC_Enable(DAC_TypeDef *dac, unsigned int ch, bool enable)
|
|
{
|
|
volatile uint32_t *reg;
|
|
|
|
EFM_ASSERT(DAC_REF_VALID(dac));
|
|
EFM_ASSERT(DAC_CH_VALID(ch));
|
|
|
|
if (!ch)
|
|
{
|
|
reg = &(dac->CH0CTRL);
|
|
}
|
|
else
|
|
{
|
|
reg = &(dac->CH1CTRL);
|
|
}
|
|
|
|
BITBAND_Peripheral(reg, _DAC_CH0CTRL_EN_SHIFT, (unsigned int)enable);
|
|
}
|
|
|
|
|
|
/***************************************************************************//**
|
|
* @brief
|
|
* Initialize DAC.
|
|
*
|
|
* @details
|
|
* Initializes common parts for both channels. In addition, channel control
|
|
* configuration must be done, please refer to DAC_InitChannel().
|
|
*
|
|
* @note
|
|
* This function will disable both channels prior to configuration.
|
|
*
|
|
* @param[in] dac
|
|
* Pointer to DAC peripheral register block.
|
|
*
|
|
* @param[in] init
|
|
* Pointer to DAC initialization structure.
|
|
******************************************************************************/
|
|
void DAC_Init(DAC_TypeDef *dac, const DAC_Init_TypeDef *init)
|
|
{
|
|
uint32_t tmp;
|
|
|
|
EFM_ASSERT(DAC_REF_VALID(dac));
|
|
|
|
/* Make sure both channels are disabled. */
|
|
BITBAND_Peripheral(&(dac->CH0CTRL), _DAC_CH0CTRL_EN_SHIFT, 0);
|
|
BITBAND_Peripheral(&(dac->CH1CTRL), _DAC_CH0CTRL_EN_SHIFT, 0);
|
|
|
|
/* Load proper calibration data depending on selected reference */
|
|
switch (init->reference)
|
|
{
|
|
case dacRef2V5:
|
|
dac->CAL = DEVINFO->DAC0CAL1;
|
|
break;
|
|
|
|
case dacRefVDD:
|
|
dac->CAL = DEVINFO->DAC0CAL2;
|
|
break;
|
|
|
|
default: /* 1.25V */
|
|
dac->CAL = DEVINFO->DAC0CAL0;
|
|
break;
|
|
}
|
|
|
|
tmp = ((uint32_t)(init->refresh) << _DAC_CTRL_REFRSEL_SHIFT) |
|
|
(((uint32_t)(init->prescale) << _DAC_CTRL_PRESC_SHIFT) & _DAC_CTRL_PRESC_MASK) |
|
|
((uint32_t)(init->reference) << _DAC_CTRL_REFSEL_SHIFT) |
|
|
((uint32_t)(init->outMode) << _DAC_CTRL_OUTMODE_SHIFT) |
|
|
((uint32_t)(init->convMode) << _DAC_CTRL_CONVMODE_SHIFT);
|
|
|
|
if (init->ch0ResetPre)
|
|
{
|
|
tmp |= DAC_CTRL_CH0PRESCRST;
|
|
}
|
|
|
|
if (init->outEnablePRS)
|
|
{
|
|
tmp |= DAC_CTRL_OUTENPRS;
|
|
}
|
|
|
|
if (init->sineEnable)
|
|
{
|
|
tmp |= DAC_CTRL_SINEMODE;
|
|
}
|
|
|
|
if (init->diff)
|
|
{
|
|
tmp |= DAC_CTRL_DIFF;
|
|
}
|
|
|
|
dac->CTRL = tmp;
|
|
}
|
|
|
|
|
|
/***************************************************************************//**
|
|
* @brief
|
|
* Initialize DAC channel.
|
|
*
|
|
* @param[in] dac
|
|
* Pointer to DAC peripheral register block.
|
|
*
|
|
* @param[in] init
|
|
* Pointer to DAC initialization structure.
|
|
*
|
|
* @param[in] ch
|
|
* Channel number to initialize.
|
|
******************************************************************************/
|
|
void DAC_InitChannel(DAC_TypeDef *dac,
|
|
const DAC_InitChannel_TypeDef *init,
|
|
unsigned int ch)
|
|
{
|
|
uint32_t tmp;
|
|
|
|
EFM_ASSERT(DAC_REF_VALID(dac));
|
|
EFM_ASSERT(DAC_CH_VALID(ch));
|
|
|
|
tmp = (uint32_t)(init->prsSel) << _DAC_CH0CTRL_PRSSEL_SHIFT;
|
|
|
|
if (init->enable)
|
|
{
|
|
tmp |= DAC_CH0CTRL_EN;
|
|
}
|
|
|
|
if (init->prsEnable)
|
|
{
|
|
tmp |= DAC_CH0CTRL_PRSEN;
|
|
}
|
|
|
|
if (init->refreshEnable)
|
|
{
|
|
tmp |= DAC_CH0CTRL_REFREN;
|
|
}
|
|
|
|
if (ch)
|
|
{
|
|
dac->CH1CTRL = tmp;
|
|
}
|
|
else
|
|
{
|
|
dac->CH0CTRL = tmp;
|
|
}
|
|
}
|
|
|
|
|
|
/***************************************************************************//**
|
|
* @brief
|
|
* Calculate prescaler value used to determine DAC clock.
|
|
*
|
|
* @details
|
|
* The DAC clock is given by: HFPERCLK / (prescale ^ 2).
|
|
*
|
|
* @param[in] dacFreq DAC frequency wanted. The frequency will automatically
|
|
* be adjusted to be below max allowed DAC clock.
|
|
*
|
|
* @param[in] hfperFreq Frequency in Hz of reference HFPER clock. Set to 0 to
|
|
* use currently defined HFPER clock setting.
|
|
*
|
|
* @return
|
|
* Prescaler value to use for DAC in order to achieve a clock value
|
|
* <= @p dacFreq.
|
|
******************************************************************************/
|
|
uint8_t DAC_PrescaleCalc(uint32_t dacFreq, uint32_t hfperFreq)
|
|
{
|
|
uint32_t ret;
|
|
|
|
/* Make sure selected DAC clock is below max value */
|
|
if (dacFreq > DAC_MAX_CLOCK)
|
|
{
|
|
dacFreq = DAC_MAX_CLOCK;
|
|
}
|
|
|
|
/* Use current HFPER frequency? */
|
|
if (!hfperFreq)
|
|
{
|
|
hfperFreq = CMU_ClockFreqGet(cmuClock_HFPER);
|
|
}
|
|
|
|
/* Iterate in order to determine best prescale value. Only a few possible */
|
|
/* values. We start with lowest prescaler value in order to get first */
|
|
/* equal or below wanted DAC frequency value. */
|
|
for (ret = 0; ret <= (_DAC_CTRL_PRESC_MASK >> _DAC_CTRL_PRESC_SHIFT); ret++)
|
|
{
|
|
if ((hfperFreq >> ret) <= dacFreq)
|
|
break;
|
|
}
|
|
|
|
return((uint8_t)ret);
|
|
}
|
|
|
|
|
|
/***************************************************************************//**
|
|
* @brief
|
|
* Reset DAC to same state as after a HW reset.
|
|
*
|
|
* @param[in] dac
|
|
* Pointer to ADC peripheral register block.
|
|
******************************************************************************/
|
|
void DAC_Reset(DAC_TypeDef *dac)
|
|
{
|
|
/* Disable channels, before resetting other registers. */
|
|
dac->CH0CTRL = _DAC_CH0CTRL_RESETVALUE;
|
|
dac->CH1CTRL = _DAC_CH1CTRL_RESETVALUE;
|
|
dac->CTRL = _DAC_CTRL_RESETVALUE;
|
|
dac->IEN = _DAC_IEN_RESETVALUE;
|
|
dac->IFC = _DAC_IFC_MASK;
|
|
dac->CAL = DEVINFO->DAC0CAL0;
|
|
dac->BIASPROG = _DAC_BIASPROG_RESETVALUE;
|
|
/* Do not reset route register, setting should be done independently */
|
|
}
|
|
|
|
|
|
/** @} (end addtogroup DAC) */
|
|
/** @} (end addtogroup EM_Library) */
|