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
25 #include <iostream>
26
27 #include "wheelencoder.h"
28
29 using namespace upm;
30 using namespace std;
31
WheelEncoder(int pin)32 WheelEncoder::WheelEncoder(int pin) :
33 m_gpio(pin)
34 {
35 m_gpio.dir(mraa::DIR_IN);
36
37 initClock();
38 m_counter = 0;
39 m_isrInstalled = false;
40 }
41
~WheelEncoder()42 WheelEncoder::~WheelEncoder()
43 {
44 stopCounter();
45 }
46
initClock()47 void WheelEncoder::initClock()
48 {
49 gettimeofday(&m_startTime, NULL);
50 }
51
getMillis()52 uint32_t WheelEncoder::getMillis()
53 {
54 struct timeval elapsed, now;
55 uint32_t elapse;
56
57 // get current time
58 gettimeofday(&now, NULL);
59
60 // compute the delta since m_startTime
61 if( (elapsed.tv_usec = now.tv_usec - m_startTime.tv_usec) < 0 )
62 {
63 elapsed.tv_usec += 1000000;
64 elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec - 1;
65 }
66 else
67 {
68 elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec;
69 }
70
71 elapse = (uint32_t)((elapsed.tv_sec * 1000) + (elapsed.tv_usec / 1000));
72
73 // never return 0
74 if (elapse == 0)
75 elapse = 1;
76
77 return elapse;
78 }
79
startCounter()80 void WheelEncoder::startCounter()
81 {
82 initClock();
83 m_counter = 0;
84
85 // install our interrupt handler
86 if (!m_isrInstalled)
87 m_gpio.isr(mraa::EDGE_RISING, &wheelISR, this);
88
89 m_isrInstalled = true;
90 }
91
stopCounter()92 void WheelEncoder::stopCounter()
93 {
94 // remove the interrupt handler
95 if (m_isrInstalled)
96 m_gpio.isrExit();
97
98 m_isrInstalled = false;
99 }
100
wheelISR(void * ctx)101 void WheelEncoder::wheelISR(void *ctx)
102 {
103 upm::WheelEncoder *This = (upm::WheelEncoder *)ctx;
104 This->m_counter++;
105 }
106
107