Diff: targets/TARGET_Silicon_Labs/TARGET_EFM32/emlib/src/em_dac.c

Revision:

149:156823d33999

Parent:

144:ef7eb2e8f9f7

Child:

150:02e0a0aed4ec

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_Silicon_Labs/TARGET_EFM32/emlib/src/em_dac.c	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,341 @@
+/***************************************************************************//**
+ * @file em_dac.c
+ * @brief Digital to Analog Coversion (DAC) Peripheral API
+ * @version 4.2.1
+ *******************************************************************************
+ * @section License
+ * <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.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: Silicon Labs has no
+ * obligation to support this Software. Silicon Labs 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.
+ *
+ * Silicon Labs 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"
+#if defined(DAC_COUNT) && (DAC_COUNT > 0)
+#include "em_cmu.h"
+#include "em_assert.h"
+#include "em_bus.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);
+  }
+
+  BUS_RegBitWrite(reg, _DAC_CH0CTRL_EN_SHIFT, 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. */
+  BUS_RegBitWrite(&(dac->CH0CTRL), _DAC_CH0CTRL_EN_SHIFT, 0);
+  BUS_RegBitWrite(&(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
+ *   Set the output signal of a DAC channel to a given value.
+ *
+ * @details
+ *   This function sets the output signal of a DAC channel by writing @p value
+ *   to the corresponding CHnDATA register.
+ *
+ * @param[in] dac
+ *   Pointer to DAC peripheral register block.
+ *
+ * @param[in] channel
+ *   Channel number to set output of.
+ *
+ * @param[in] value
+ *   Value to write to the channel output register CHnDATA.
+ ******************************************************************************/
+void DAC_ChannelOutputSet( DAC_TypeDef *dac,
+                           unsigned int channel,
+                           uint32_t     value )
+{
+  switch(channel)
+  {
+    case 0:
+      DAC_Channel0OutputSet(dac, value);
+      break;
+    case 1:
+      DAC_Channel1OutputSet(dac, value);
+      break;
+    default:
+      EFM_ASSERT(0);
+      break;
+  }
+}
+
+
+/***************************************************************************//**
+ * @brief
+ *   Calculate prescaler value used to determine DAC clock.
+ *
+ * @details
+ *   The DAC clock is given by: HFPERCLK / (prescale ^ 2). If the requested
+ *   DAC frequency is low and the max prescaler value can not adjust the
+ *   actual DAC frequency lower than the requested DAC frequency, then the
+ *   max prescaler value is returned, resulting in a higher DAC frequency
+ *   than requested.
+ *
+ * @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;
+  }
+
+  /* If ret is higher than the max prescaler value, make sure to return
+     the max value. */
+  if (ret > (_DAC_CTRL_PRESC_MASK >> _DAC_CTRL_PRESC_SHIFT))
+  {
+    ret = _DAC_CTRL_PRESC_MASK >> _DAC_CTRL_PRESC_SHIFT;
+  }
+
+  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) */
+#endif /* defined(DAC_COUNT) && (DAC_COUNT > 0) */