AnalogIn.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00020  * SOFTWARE.
00021  */
00022 #ifndef MBED_ANALOGIN_H
00023 #define MBED_ANALOGIN_H
00024 
00025 #include "platform.h"
00026 
00027 #if DEVICE_ANALOGIN
00028 
00029 #include "analogin_api.h"
00030 
00031 namespace mbed {
00032 
00033 /** An analog input, used for reading the voltage on a pin
00034  *
00035  * Example:
00036  * @code
00037  * // Print messages when the AnalogIn is greater than 50%
00038  *
00039  * #include "mbed.h"
00040  *
00041  * AnalogIn temperature(p20);
00042  *
00043  * int main() {
00044  *     while(1) {
00045  *         if(temperature > 0.5) {
00046  *             printf("Too hot! (%f)", temperature.read());
00047  *         }
00048  *     }
00049  * }
00050  * @endcode
00051  */
00052 class AnalogIn {
00053 
00054 public:
00055 
00056     /** Create an AnalogIn, connected to the specified pin
00057      *
00058      * @param pin AnalogIn pin to connect to
00059      * @param name (optional) A string to identify the object
00060      */
00061     AnalogIn(PinName pin) {
00062         analogin_init(&_adc, pin);
00063     }
00064 
00065     /** Read the input voltage, represented as a float in the range [0.0, 1.0]
00066      *
00067      * @returns A floating-point value representing the current input voltage, measured as a percentage
00068      */
00069     float read() {
00070         return analogin_read(&_adc);
00071     }
00072 
00073     /** Read the input voltage, represented as an unsigned short in the range [0x0, 0xFFFF]
00074      *
00075      * @returns
00076      *   16-bit unsigned short representing the current input voltage, normalised to a 16-bit value
00077      */
00078     unsigned short read_u16() {
00079         return analogin_read_u16(&_adc);
00080     }
00081 
00082 #ifdef MBED_OPERATORS
00083     /** An operator shorthand for read()
00084      *
00085      * The float() operator can be used as a shorthand for read() to simplify common code sequences
00086      *
00087      * Example:
00088      * @code
00089      * float x = volume.read();
00090      * float x = volume;
00091      *
00092      * if(volume.read() > 0.25) { ... }
00093      * if(volume > 0.25) { ... }
00094      * @endcode
00095      */
00096     operator float() {
00097         return read();
00098     }
00099 #endif
00100 
00101 protected:
00102     analogin_t _adc;
00103 };
00104 
00105 } // namespace mbed
00106 
00107 #endif
00108 
00109 #endif
00110