![](/media/cache/group/default_image.jpg.50x50_q85.jpg)
This is a very simple guide, reviewing the steps required to get Blinky working on an Mbed OS platform.
Dependencies: mbed Adafruit_GFX
Diff: ultrasonic.cpp
- Revision:
- 95:250afd53b710
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/ultrasonic.cpp Sat Jun 08 12:00:38 2019 +0000 @@ -0,0 +1,115 @@ +#include "ultrasonic.h" + +// generate a 10 us pulse to start HCSR04 ulrasonic sensor and +// enable IRQ for echo pin. +Ultrasonic::Ultrasonic(PinName trigPin, PinName echoPin, float timeout, bool mode, float time) : + _trig(trigPin), _echo(echoPin), _toVal(timeout), _pc(PA_2, PA_3), _repeat(mode), _repeatD(time){ + _timer.reset(); + _echo.rise(this, &Ultrasonic::_startT); + _echo.fall(this, &Ultrasonic::_endT); + _echo.mode(PullUp); + _echo.disable_irq(); + _pc.baud(115200); +} + + +Ultrasonic::~Ultrasonic(){} + +int Ultrasonic::getDistance(void) { + calculateDistance(); + return _distance; +} + +void Ultrasonic::calculateDistance(void) { + clearStatus(); + + trig(); + getPulseDuration(); + + if (_pulseDuration >= 0) _distance = _pulseDuration / 29 / 2; + else _distance = -1; + +} + +void Ultrasonic::trig(void) { + _echo.enable_irq(); + _trig = 1; + wait_us(10); + _trig = 0; +} + +int Ultrasonic::getPulseDuration(void) { + + while (!_break) { + _pc.printf("\r"); + } // wait signal + // we need to change + + _break = 0; + _echo.disable_irq(); + + if (_end >= 0) _pulseDuration = _end - _start; + else _pulseDuration = -1; + + return _pulseDuration; +} + +int Ultrasonic::getStatus(void) { + return _done; +} + +void Ultrasonic::clearStatus(void) { + _done = 0; + _pulseDuration = 0; + _distance = 0; + _start = -1; + _end = -1; + _trig = 0; +} + +void Ultrasonic::pauseMeasure(void) { + _done = 1; +} + +void Ultrasonic::_startT(void) { + _timer.start(); + _start = _timer.read_us(); + _timeout.attach(callback(this, &Ultrasonic::_timeout_cb), _toVal); +} + +void Ultrasonic::_endT(void) { + _timeout.detach(); + _end = _timer.read_us(); + _timer.stop(); + _timer.reset(); + _break = 1; +} + +void Ultrasonic::_timeout_cb(void) { + _timer.stop(); + _timer.reset(); + _break = 1; +} + +void Ultrasonic::setMode(bool mode){ + _repeat = mode; +} + +void Ultrasonic::printDistance(float interval){ + + int num = (int)(1/interval); + + if(_repeat == true) + { + for(int i=0; i<num; i++) + { + _pc.printf("distance: %d\r\n", getDistance()); + wait(interval/2); + } + } + + else + _pc.printf("distance: %d\r\n", getDistance()); + + num = 0; +}