piezo_bz.cpp

00001 /*
00002  * Mbed library program
00003  *  Control Piezo Transducer
00004  *
00005  * Copyright (c) 2018 Kenji Arai / JH1PJL
00006  *  http://www.page.sannet.ne.jp/kenjia/index.html
00007  *  http://mbed.org/users/kenjiArai/
00008  *      Created:    Feburary  28th, 2018
00009  *      Revised:    March      3rd, 2018
00010  */
00011 
00012 #include "mbed.h"
00013 #include "piezo_bz.h"
00014 
00015 PIEZO_BZ::PIEZO_BZ(PinName pin, uint32_t f, uint32_t on_off_time)
00016     :  _pin(pin)
00017 {
00018     out = false;
00019     _pin.write(0);
00020     freq = f;
00021     if (freq < 50) {
00022         freq = 50;
00023     } else if (freq > 10000) {
00024         freq = 10000;
00025     }
00026     flag_run = false;
00027     _t0.attach_us(callback(this, &PIEZO_BZ::create_freq_irq), 500000 / freq);
00028     t_onoff  = on_off_time;
00029     if (t_onoff == 0) {
00030         flag_continuous = true;
00031         _t1.attach_us(
00032             callback(this, &PIEZO_BZ::create_onoff_irq),
00033             1000000000 // 1000sec
00034         );
00035     } else {
00036         flag_continuous = false;
00037         _t1.attach_us(
00038             callback(this, &PIEZO_BZ::create_onoff_irq),
00039             t_onoff * 1000
00040         );
00041     }
00042 }
00043 
00044 PIEZO_BZ::~PIEZO_BZ()
00045 {
00046     _t0.detach();
00047     _t1.detach();
00048 }
00049 
00050 void PIEZO_BZ::start()
00051 {
00052     flag_run = true;
00053 }
00054 
00055 void PIEZO_BZ::stop()
00056 {
00057     flag_run = false;
00058 }
00059 
00060 void PIEZO_BZ::change_frequency(uint32_t f)
00061 {
00062     _t0.detach();
00063     freq = f;
00064     if (freq < 300) {
00065         freq = 300;
00066     } else if (freq > 10000) {
00067         freq = 10000;
00068     }
00069     _t0.attach_us(callback(this, &PIEZO_BZ::create_freq_irq), 500000 / freq);
00070 }
00071 
00072 void PIEZO_BZ::change_on_off(uint32_t on_off_time)
00073 {
00074     _t1.detach();
00075     t_onoff  = on_off_time;
00076     if (t_onoff == 0) {
00077         flag_continuous = true;
00078         _t1.attach_us(
00079             callback(this, &PIEZO_BZ::create_onoff_irq),
00080             1000000000U // 1000sec
00081         );
00082     } else {
00083         flag_continuous = false;
00084         _t1.attach_us(
00085             callback(this, &PIEZO_BZ::create_onoff_irq),
00086             t_onoff * 1000U
00087         );
00088     }
00089 }
00090 
00091 void PIEZO_BZ::create_freq_irq(void)
00092 {
00093     // <point A>
00094     if (!flag_run) {
00095         _pin.write(0);
00096         return;
00097     }
00098     if (!flag_continuous) {
00099         if (!flag_onoff) {
00100             _pin.write(0);
00101             return;
00102         }
00103     }
00104     _pin.write(out);
00105     out = !out;
00106     // <point B>
00107     // Processing time from <point A> to <point B> is 200 to 230ns
00108     // measured on Nucleo-F446RE board (System clock 180MHz)
00109 }
00110 
00111 void PIEZO_BZ::create_onoff_irq(void)
00112 {
00113     // <point C>
00114     if (flag_continuous) {
00115         flag_onoff = true;
00116     } else {
00117         flag_onoff = !flag_onoff;
00118     }
00119     // <point D>
00120     // Processing time from <point C> to <point D> is 120 to 140ns
00121     // measured on Nucleo-F446RE board (System clock 180MHz)
00122 }