tmk_core/tool/mbed/mbed-sdk/libraries/mbed/api/AnalogIn.h

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #ifndef MBED_ANALOGIN_H
  17 #define MBED_ANALOGIN_H
  18
  19 #include "platform.h"
  20
  21 #if DEVICE_ANALOGIN
  22
  23 #include "analogin_api.h"
  24
  25 namespace mbed {
  26
  27 /** An analog input, used for reading the voltage on a pin
  28  *
  29  * Example:
  30  * @code
  31  * // Print messages when the AnalogIn is greater than 50%
  32  *
  33  * #include "mbed.h"
  34  *
  35  * AnalogIn temperature(p20);
  36  *
  37  * int main() {
  38  *     while(1) {
  39  *         if(temperature > 0.5) {
  40  *             printf("Too hot! (%f)", temperature.read());
  41  *         }
  42  *     }
  43  * }
  44  * @endcode
  45  */
  46 class AnalogIn {
  47
  48 public:
  49
  50     /** Create an AnalogIn, connected to the specified pin
  51      *
  52      * @param pin AnalogIn pin to connect to
  53      * @param name (optional) A string to identify the object
  54      */
  55     AnalogIn(PinName pin) {
  56         analogin_init(&_adc, pin);
  57     }
  58
  59     /** Read the input voltage, represented as a float in the range [0.0, 1.0]
  60      *
  61      * @returns A floating-point value representing the current input voltage, measured as a percentage
  62      */
  63     float read() {
  64         return analogin_read(&_adc);
  65     }
  66
  67     /** Read the input voltage, represented as an unsigned short in the range [0x0, 0xFFFF]
  68      *
  69      * @returns
  70      *   16-bit unsigned short representing the current input voltage, normalised to a 16-bit value
  71      */
  72     unsigned short read_u16() {
  73         return analogin_read_u16(&_adc);
  74     }
  75
  76 #ifdef MBED_OPERATORS
  77     /** An operator shorthand for read()
  78      *
  79      * The float() operator can be used as a shorthand for read() to simplify common code sequences
  80      *
  81      * Example:
  82      * @code
  83      * float x = volume.read();
  84      * float x = volume;
  85      *
  86      * if(volume.read() > 0.25) { ... }
  87      * if(volume > 0.25) { ... }
  88      * @endcode
  89      */
  90     operator float() {
  91         return read();
  92     }
  93 #endif
  94
  95 protected:
  96     analogin_t _adc;
  97 };
  98
  99 } // namespace mbed
 100
 101 #endif
 102
 103 #endif