stm32f0xx_dac.c

stm32f0固件库

/**
  ******************************************************************************
  * @file    stm32f0xx_dac.c
  * @author  MCD Application Team
  * @version V1.0.0
  * @date    23-March-2012
  * @brief   This file provides firmware functions to manage the following 
  *          functionalities of the Digital-to-Analog Converter (DAC) peripheral:
  *           + DAC channel configuration: trigger, output buffer, data format
  *           + DMA management
  *           + Interrupts and flags management
  *
  *  @verbatim
  *
 ===============================================================================
                        ##### DAC Peripheral features #####
 ===============================================================================
    [..] The device integrates one 12-bit Digital Analog Converters refered as
         DAC channel1 with DAC_OUT1 (PA4) as output
  
    [..] Digital to Analog conversion can be non-triggered using DAC_Trigger_None
         and DAC_OUT1 is available once writing to DHRx register using 
         DAC_SetChannel1Data().
  
    [..] Digital to Analog conversion can be triggered by:
         (#) External event: EXTI Line 9 (any GPIOx_Pin9) using DAC_Trigger_Ext_IT9.
             The used pin (GPIOx_Pin9) must be configured in input mode.
  
         (#) Timers TRGO: TIM2, TIM3, TIM6 and TIM15 
             (DAC_Trigger_T2_TRGO, DAC_Trigger_T3_TRGO...)
             The timer TRGO event should be selected using TIM_SelectOutputTrigger()
  
         (#) Software using DAC_Trigger_Software
  
    [..] The DAC channel 1 integrates an output buffer that can be used to 
         reduce the output impedance, and to drive external loads directly
         without having to add an external operational amplifier.
         To enable the output buffer use  
         DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
  
    [..] Refer to the device datasheet for more details about output impedance
         value with and without output buffer.
  
    [..] The DAC data format can be:
         (#) 8-bit right alignment using DAC_Align_8b_R
         (#) 12-bit left alignment using DAC_Align_12b_L
         (#) 12-bit right alignment using DAC_Align_12b_R
  
    [..] The analog output voltage on each DAC channel pin is determined
         by the following equation: DAC_OUTx = VREF+ * DOR / 4095
         with  DOR is the Data Output Register
         VEF+ is the input voltage reference (refer to the device datasheet)
         e.g. To set DAC_OUT1 to 0.7V, use
         DAC_SetChannel1Data(DAC_Align_12b_R, 868);
         Assuming that VREF+ = 3.3, DAC_OUT1 = (3.3 * 868) / 4095 = 0.7V
  
    [..] A DMA1 request can be generated when an external trigger (but not
         a software trigger) occurs if DMA1 requests are enabled using
         DAC_DMACmd()
         DMA1 requests are mapped as following:
         (+) DAC channel1 is mapped on DMA1 channel3 which must be already 
             configured
    
                      ##### How to use this driver #####
 ===============================================================================
    [..]
         (+) Enable DAC APB1 clock to get write access to DAC registers
             using RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE)
              
         (+) Configure DAC_OUT1 (DAC_OUT1: PA4) in analog mode
             using GPIO_Init() function  
              
         (+) Configure the DAC channel using DAC_Init()
              
         (+) Enable the DAC channel using DAC_Cmd()
  
    @endverbatim
  *
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT 2012 STMicroelectronics</center></h2>
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        http://www.st.com/software_license_agreement_liberty_v2
  *
  * Unless required by applicable law or agreed to in writing, software 
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "stm32f0xx_dac.h"

/** @addtogroup STM32F0xx_StdPeriph_Driver
  * @{
  */

/** @defgroup DAC 
  * @brief DAC driver modules
  * @{
  */ 

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* CR register Mask */
#define CR_CLEAR_MASK              ((uint32_t)0x0000003E)

/* DHR registers offsets */
#define DHR12R1_OFFSET             ((uint32_t)0x00000008)

/* DOR register offset */
#define DOR_OFFSET                 ((uint32_t)0x0000002C)

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/

/** @defgroup DAC_Private_Functions
  * @{
  */ 

/** @defgroup DAC_Group1 DAC channels configuration
 *  @brief   DAC channels configuration: trigger, output buffer, data format 
 *
@verbatim
 ===============================================================================
  ##### DAC channels configuration: trigger, output buffer, data format #####
 ===============================================================================  

@endverbatim
  * @{
  */

/**
  * @brief  Deinitializes the DAC peripheral registers to their default reset values.
  * @param  None
  * @retval None
  */
void DAC_DeInit(void)
{
  /* Enable DAC reset state */
  RCC_APB1PeriphResetCmd(RCC_APB1Periph_DAC, ENABLE);
  /* Release DAC from reset state */
  RCC_APB1PeriphResetCmd(RCC_APB1Periph_DAC, DISABLE);
}

/**
  * @brief  Initializes the DAC peripheral according to the specified 
  *         parameters in the DAC_InitStruct.
  * @param  DAC_Channel: the selected DAC channel. 
  *   This parameter can be one of the following values:
  *     @arg DAC_Channel_1: DAC Channel1 selected
  * @param  DAC_InitStruct: pointer to a DAC_InitTypeDef structure that
  *         contains the configuration information for the specified DAC channel.
  *
  * @retval None
  */
void DAC_Init(uint32_t DAC_Channel, DAC_InitTypeDef* DAC_InitStruct)
{
  uint32_t tmpreg1 = 0, tmpreg2 = 0;

  /* Check the DAC parameters */
  assert_param(IS_DAC_CHANNEL(DAC_Channel));
  assert_param(IS_DAC_TRIGGER(DAC_InitStruct->DAC_Trigger));
  assert_param(IS_DAC_OUTPUT_BUFFER_STATE(DAC_InitStruct->DAC_OutputBuffer));

  /*---------------------------- DAC CR Configuration ------------------------*/
  /* Get the DAC CR value */
  tmpreg1 = DAC->CR;

  /* Clear BOFFx, TENx, TSELx bits */
  tmpreg1 &= ~(CR_CLEAR_MASK << DAC_Channel);

  /* Configure for the selected DAC channel: buffer output, trigger */
  /* Set TSELx and TENx bits according to DAC_Trigger value */
  /* Set BOFFx bit according to DAC_OutputBuffer value */   
  tmpreg2 = (DAC_InitStruct->DAC_Trigger | DAC_InitStruct->DAC_OutputBuffer);

  /* Calculate CR register value depending on DAC_Channel */
  tmpreg1 |= tmpreg2 << DAC_Channel;

  /* Write to DAC CR */
  DAC->CR = tmpreg1;
}

/**
  * @brief  Fills each DAC_InitStruct member with its default value.
  * @param  DAC_InitStruct : pointer to a DAC_InitTypeDef structure which will 
  *         be initialized.
  * @retval None
  */
void DAC_StructInit(DAC_InitTypeDef* DAC_InitStruct)
{
/*--------------- Reset DAC init structure parameters values -----------------*/
  /* Initialize the DAC_Trigger member */
  DAC_InitStruct->DAC_Trigger = DAC_Trigger_None;
  /* Initialize the DAC_OutputBuffer member */
  DAC_InitStruct->DAC_OutputBuffer = DAC_OutputBuffer_Enable;
}

/**
  * @brief  Enables or disables the specified DAC channel.
  * @param  DAC_Channel: The selected DAC channel. 
  *   This parameter can be one of the following values:
  *     @arg DAC_Channel_1: DAC Channel1 selected
  * @param  NewState: new state of the DAC channel. 
  *      This parameter can be: ENABLE or DISABLE.
  * @note When the DAC channel is enabled the trigger source can no more
  *       be modified.
  * @retval None
  */
void DAC_Cmd(uint32_t DAC_Channel, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_DAC_CHANNEL(DAC_Channel));
  assert_param(IS_FUNCTIONAL_STATE(NewState));

  if (NewState != DISABLE)
  {
    /* Enable the selected DAC channel */
    DAC->CR |= (DAC_CR_EN1 << DAC_Channel);
  }
  else
  {
    /* Disable the selected DAC channel */
    DAC->CR &= (~(DAC_CR_EN1 << DAC_Channel));
  }
}

/**
  * @brief  Enables or disables the selected DAC channel software trigger.
  * @param  DAC_Channel: the selected DAC channel. 
  *   This parameter can be one of the following values:
  *     @arg DAC_Channel_1: DAC Channel1 selected
  * @param  NewState: new state of the selected DAC channel software trigger.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void DAC_SoftwareTriggerCmd(uint32_t DAC_Channel, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_DAC_CHANNEL(DAC_Channel));
  assert_param(IS_FUNCTIONAL_STATE(NewState));

  if (NewState != DISABLE)
  {
    /* Enable software trigger for the selected DAC channel */
    DAC->SWTRIGR |= (uint32_t)DAC_SWTRIGR_SWTRIG1 << (DAC_Channel >> 4);
  }
  else
  {
    /* Disable software trigger for the selected DAC channel */
    DAC->SWTRIGR &= ~((uint32_t)DAC_SWTRIGR_SWTRIG1 << (DAC_Channel >> 4));
  }
}

/**
  * @brief  Set the specified data holding register value for DAC channel1.
  * @param  DAC_Align: Specifies the data alignment for DAC channel1.
  *   This parameter can be one of the following values: