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RIOT/cpu/stm32_common/periph/dac.c 2.71 KB
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  /*
   * Copyright (C) 2014 Simon Brummer
   *               2015-2016 Freie Universitรคt Berlin
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  /**
   * @ingroup     cpu_stm32_common
   * @ingroup     drivers_periph_dac
   * @{
   *
   * @file
   * @brief       Low-level DAC driver implementation
   *
   * @author      Simon Brummer <simon.brummer@haw-hamburg.de>
   * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
   *
   * @}
   */
  
  #include "cpu.h"
  #include "assert.h"
  #include "periph/dac.h"
  
  /* only compile this, if the CPU has a DAC */
  #ifdef DAC_NUMOF
  
  /* DAC channel enable bits */
  #ifdef DAC_CR_EN2
  #define EN_MASK             (DAC_CR_EN1 | DAC_CR_EN2)
  #else
  #define EN_MASK             (DAC_CR_EN1)
  #endif
  
  /* get RCC bit */
  #ifdef RCC_APB1ENR_DAC1EN
  #define RCC_BIT             (RCC_APB1ENR_DAC1EN)
  #else
  #define RCC_BIT             (RCC_APB1ENR_DACEN)
  #endif
  
  /* deduct DAC device from given line channel */
  static inline DAC_TypeDef *dev(dac_t line)
  {
  #if defined(DAC2)
      return (dac_config[line].chan > 1) ? DAC2 : DAC1;
  #elif defined (DAC1)
      return DAC1;
  #else
      return DAC;
  #endif
  }
  
  int8_t dac_init(dac_t line)
  {
      if (line >= DAC_NUMOF) {
          return DAC_NOLINE;
      }
  
      /* configure pin */
      gpio_init_analog(dac_config[line].pin);
  
      /* reset output and enable the line's channel */
      dac_poweron(line);
      dac_set(line, 0);
  
      return DAC_OK;
  }
  
  void dac_set(dac_t line, uint16_t value)
  {
      assert(line < DAC_NUMOF);
  
      /* scale set value to 12-bit */
      value = (value >> 4);
  
  #ifdef DAC_DHR12R2_DACC2DHR
      if (dac_config[line].chan & 0x01) {
          dev(line)->DHR12R2 = value;
      }
      else {
          dev(line)->DHR12R1 = value;
      }
  #else
      dev(line)->DHR12R1 = value;
  #endif
  }
  
  void dac_poweron(dac_t line)
  {
      assert(line < DAC_NUMOF);
  
      /* enable the DAC's clock */
  #if defined(DAC2)
      periph_clk_en(APB1, (dac_config[line].chan > 1) ?
                    RCC_APB1ENR_DAC2EN : RCC_APB1ENR_DAC1EN);
  #else
      periph_clk_en(APB1, RCC_BIT);
  #endif
  
      /* enable corresponding DAC channel */
      dev(line)->CR |= (1 << (16 * (dac_config[line].chan & 0x01)));
  }
  
  void dac_poweroff(dac_t line)
  {
      assert(line < DAC_NUMOF);
  
      /* disable corresponding channel */
      dev(line)->CR &= ~(1 << (16 * (dac_config[line].chan & 0x01)));
  
      /* disable the DAC's clock in case no channel is active anymore */
      if (!(dev(line)->CR & EN_MASK)) {
  #if defined(DAC2)
          periph_clk_dis(APB1, (dac_config[line].chan > 1) ?
                        RCC_APB1ENR_DAC2EN : RCC_APB1ENR_DAC1EN);
  #else
          periph_clk_dis(APB1, RCC_BIT);
  #endif
      }
  }
  
  #else
  typedef int dont_be_pedantic;
  #endif /* DAC */