1 /*
2  * Author: Jon Trulson <jtrulson@ics.com>
3  * Copyright (c) 2015 Intel Corporation.
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining
6  * a copy of this software and associated documentation files (the
7  * "Software"), to deal in the Software without restriction, including
8  * without limitation the rights to use, copy, modify, merge, publish,
9  * distribute, sublicense, and/or sell copies of the Software, and to
10  * permit persons to whom the Software is furnished to do so, subject to
11  * the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be
14  * included in all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
22  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23  */
24 #pragma once
25 
26 #include <string>
27 #include <stdint.h>
28 #include <sys/time.h>
29 #include <mraa/gpio.h>
30 
31 namespace upm {
32 
33 /**
34  * @brief Grove Rotary Encoder library
35  * @defgroup rotaryencoder libupm-rotaryencoder
36  * @ingroup seeed gpio other hak
37  */
38 /**
39  * @library rotaryencoder
40  * @sensor rotaryencoder
41  * @comname Grove Rotary Encoder
42  * @type other
43  * @man seeed
44  * @web http://www.seeedstudio.com/wiki/Grove_-_Encoder
45  * @con gpio
46  * @kit hak
47  *
48  * @brief API for the Grove Rotary Encoder
49  *
50  * UPM module for the Grove rotary encoder. This rotary encoder
51  * encodes a rotation signal into electronic pulses that can be used
52  * to measure rotation and direction. It is useful in cases where a
53  * rotary knob is required, but using a potentiometer is not
54  * desirable. A rotary encoder can turn a full 360 degrees
55  * without a stop and does not place a resistive load on the
56  * circuit, as is the case with a potentiometer.
57  *
58  * This module maintains a position that is incremented or
59  * decremented according to the rotation on the encoder.
60  *
61  * @image html rotaryencoder.jpg
62  * @snippet rotaryencoder.cxx Interesting
63  */
64   class RotaryEncoder {
65   public:
66     /**
67      * RotaryEncoder constructor
68      *
69      * @param pinA Digital pin to use for signal A
70      * @param pinB Digital pin to use for signal B
71      */
72     RotaryEncoder(int pinA, int pinB);
73     /**
74      * RotaryEncoder destructor
75      */
76     ~RotaryEncoder();
77 
78     /**
79      * Resets the position to a given number; default is 0.
80      *
81      * @param count Integer to initialize the position to
82      */
83     void initPosition(int count=0);
84 
85     /**
86      * Gets the position value
87      *
88      */
89     int position();
90 
91   private:
92     /**
93      * Interrupt service routine (ISR) for signal A
94      *
95      * @param ctx User context for the ISR (*this pointer)
96      */
97     static void signalAISR(void *ctx);
98 
99     volatile int m_position;
100     mraa_gpio_context m_gpioA;
101     mraa_gpio_context m_gpioB;
102   };
103 }
104 
105 
106