PulseGenerator.cpp

00001 /**     Pulse Fenerator cpp file
00002  *
00003  *  \file   PulseFenerator.cpp
00004  *  \author Akifumi Takahashi
00005  *  \date   2018.nov.08-
00006  *  \version    1.0.2018.nov
00007  */
00008 #include "PulseGenerator.h"
00009 PulseGenerator::PulseGenerator():
00010     m_width(200),
00011     m_period(5000)
00012 {
00013     m_clockperiod = GCD(m_width, m_period);
00014     m_rt = (m_period - m_width) / m_clockperiod;
00015     m_ft = m_width / m_clockperiod;
00016     m_wavestatus = false;
00017 }
00018 
00019 int8_t PulseGenerator::setWaveform(
00020     const uint16_t arg_pulsewidth,///< required in [us]
00021     const uint16_t arg_pulsefreq  ///< required in [Hz] > 15 [Hz]
00022 )
00023 {
00024     uint16_t tmp_width  = m_width;
00025     uint16_t tmp_period = m_period;
00026 
00027     m_width = arg_pulsewidth;
00028     //  freq is required over 15 due to the range of the type of the period
00029     m_period= Period_us(arg_pulsefreq > 15 ? arg_pulsefreq : 16);
00030 
00031     if(m_width > m_period / 2) {
00032         m_width  = tmp_width;
00033         m_period = tmp_period;
00034         return -1;
00035     }
00036     return 0;
00037 }
00038 
00039 
00040 void PulseGenerator::generatePulseWave()
00041 {
00042     static uint16_t l_counter = 0;
00043 
00044     l_counter++;
00045     if(m_wavestatus == false && l_counter >= m_rt ) {
00046         m_wavestatus = true;
00047         l_counter = 0;
00048     } else 
00049     if (m_wavestatus == true && l_counter >= m_ft) {
00050         m_wavestatus = false;
00051         l_counter = 0;
00052     }
00053 }
00054 
00055 void PulseGenerator::startPulseWave()
00056 {
00057     m_clockperiod = GCD(m_width, m_period);
00058     m_rt = (m_period - m_width) / m_clockperiod;
00059     m_ft = m_width / m_clockperiod;
00060     m_ticker.attach_us(callback(this, &PulseGenerator::generatePulseWave), m_clockperiod);
00061 }
00062 
00063 void PulseGenerator::stopPulseWave()
00064 {
00065     m_wavestatus = false;
00066     m_ticker.detach();
00067 }
00068 
00069 uint16_t Period_us(const uint16_t arg_freq)
00070 {
00071     uint16_t l_period, l_carried;
00072 
00073     //  culc integer part of 1/freq * 10^6
00074     l_period = (uint16_t)(1000000 / arg_freq);
00075 
00076     //  round factorial part of 1/freq * 10^6
00077     l_carried = (uint16_t)(((1000000 % arg_freq) > (arg_freq / 2)) ? 1 : 0);
00078 
00079     return l_period + l_carried;
00080 }
00081 
00082 uint16_t GCD(uint16_t arg1, uint16_t arg2)
00083 {
00084     uint16_t a,b,r;
00085 
00086     if (arg1 == 0 || arg2 == 0) return 0;
00087     if(arg1 > arg2) {
00088         a = arg1;
00089         b = arg2;
00090     } else {
00091         a = arg2;
00092         b = arg1;
00093     }
00094 
00095     //Eukleides Algorithm
00096     r = a % b;
00097     while(r != 0) {
00098         a = b;
00099         b = r;
00100         r = a % b;
00101     }
00102 
00103     return b;
00104 }