text: /* mbed Microcontroller Library
   * Copyright (c) 2006-2013 ARM Limited
   *
   * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
   *
   * 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.
   */
  #include "mbed_assert.h"
  #include "analogout_api.h"
  #include "cmsis.h"
  #include "pinmap.h"
  
  static const PinMap PinMap_DAC[] = {
      {P0_26, DAC_0, 2},
      {NC   , NC   , 0}
  };
  
  void analogout_init(dac_t *obj, PinName pin) {
      obj->dac = (DACName)pinmap_peripheral(pin, PinMap_DAC);
      MBED_ASSERT(obj->dac != (DACName)NC);
      
      // power is on by default, set DAC clk divider is /4
      LPC_SC->PCLKSEL0 &= ~(0x3 << 22);
      
      // map out (must be done before accessing registers)
      pinmap_pinout(pin, PinMap_DAC);
      
      analogout_write_u16(obj, 0);
  }
  
  void analogout_free(dac_t *obj) {}
  
  static inline void dac_write(int value) {
      value &= 0x3FF; // 10-bit
      
      // Set the DAC output
      LPC_DAC->DACR = (0 << 16)       // bias = 0
                    | (value << 6);
  }
  
  static inline int dac_read() {
      return (LPC_DAC->DACR >> 6) & 0x3FF;
  }
  
  void analogout_write(dac_t *obj, float value) {
      if (value < 0.0f) {
          dac_write(0);
      } else if (value > 1.0f) {
          dac_write(0x3FF);
      } else {
          dac_write(value * (float)0x3FF);
      }
  }
  
  void analogout_write_u16(dac_t *obj, uint16_t value) {
      dac_write(value >> 6); // 10-bit
  }
  
  float analogout_read(dac_t *obj) {
      uint32_t value = dac_read();
      return (float)value * (1.0f / (float)0x3FF);
  }
  
  uint16_t analogout_read_u16(dac_t *obj) {
      uint32_t value = dac_read(); // 10-bit
      return (value << 6) | ((value >> 4) & 0x003F);
  }
  