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RIOT/cpu/kinetis_common/periph/dac.c 1.84 KB
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  /*
   * Copyright (C) 2016 Eistec AB
   *
   * 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_kinetis_common_dac
   *
   * @{
   *
   * @file
   * @brief       Low-level DAC driver implementation
   *
   * This driver uses the 12-bit in-CPU DAC module. The 6-bit digital-to-analog
   * converter inside the CMP module is _not_ used by this implementation.
   *
   * @author      Joakim Nohlgård <joakim.nohlgard@eistec.se>
   *
   * @}
   */
  
  #include <stdint.h>
  
  #include "cpu.h"
  #include "periph/dac.h"
  #include "periph_conf.h"
  
  static const dac_conf_t dac_config[] = DAC_CONFIG;
  
  int8_t dac_init(dac_t line)
  {
      DAC_Type *dac;
      if ((unsigned int)line >= DAC_NUMOF) {
          return -1;
      }
  
      dac = dac_config[line].dev;
  
      /* Enable module clock */
      *(dac_config[line].clk_gate) = 1;
  
      /* Select VDDA as voltage reference */
      dac->C0 = (DAC_C0_DACRFS_MASK);
  
      /* Disable DMA and buffering */
      dac->C1 = 0;
      dac->C2 = 0;
  
      /* Power on */
      dac_poweron(line);
  
      /* Set output value to zero */
      dac_set(line, 0);
      return 0;
  }
  
  void dac_set(dac_t line, uint16_t value)
  {
      DAC_Type *dac;
  
      if ((unsigned int)line >= DAC_NUMOF) {
          return;
      }
  
      dac = dac_config[line].dev;
  
      /* Scale to 12 bit */
      value = value >> ((sizeof(value) * 8) - 12);
  
      dac->DAT[0].DATH = ((value >> 8) & 0xff);
      dac->DAT[0].DATL = (value & 0xff);
  }
  
  static inline void _dac_set_power(dac_t line, uint8_t value)
  {
      DAC_Type *dac;
  
      if ((unsigned int)line >= DAC_NUMOF) {
          return;
      }
  
      dac = dac_config[line].dev;
  
      BITBAND_REG8(dac->C0, DAC_C0_DACEN_SHIFT) = value;
  }
  
  void dac_poweron(dac_t line)
  {
      _dac_set_power(line, 1);
  }
  
  void dac_poweroff(dac_t line)
  {
      _dac_set_power(line, 0);
  }