Diff: main.cpp

Branch:

CLASS_IMPLEMENTATION

Revision:

2:aba8d0d53190

Parent:

0:6fd0fbcfc7e1

Child:

3:cb5931861f4e

--- a/main.cpp	Sun Dec 20 21:24:00 2015 +0000
+++ b/main.cpp	Sun Dec 20 21:24:45 2015 +0000
@@ -9,6 +9,11 @@
 #define CALC_COEFF          (1000.0f*340.0f/2)
 #define TICKS_RANGE_MAX     (15000)
 #define TICKS_RANGE_MIN     (150)
+#define TRIG_PULSE_US       (500)
+
+
+typedef enum { IDLE, STARTED, COMPLETED, TIMEOUT, OUT_OF_RANGE_MIN, OUT_OF_RANGE_MAX, ERROR_SIG } Distance_HC_SR04_state;
+
 
 TextLCD lcd(PA_8, PA_7, PA_9, PA_1, PB_5, PA_10, TextLCD::LCD16x2);
 
@@ -23,13 +28,136 @@
 
 static Timeout timeout;
 
-static volatile enum { IDLE, STARTED, COMPLETED, TIMEOUT, OUT_OF_RANGE_MIN, OUT_OF_RANGE_MAX, ERROR_SIG } state;
+static volatile Distance_HC_SR04_state state;
 
 void tout(void) {
     if (state == STARTED) 
         state = TIMEOUT;
 }
 
+
+class Distance_HC_SR04 {
+public:
+    Distance_HC_SR04(PinName trig, PinName echo, uint32_t tout_us = TIMEOUT_DELAY_US, float coeff = CALC_COEFF) : _trig(trig), _echo(echo), _tout_us(tout_us), _coeff(coeff) {
+        _trig = 0;
+        _state = IDLE;
+    }
+
+    void trigger(void) {
+        if (_state == IDLE && _echo == 0) {
+            _timeout.detach();
+            _timer.stop();
+            _timer.reset();   
+
+            _trig = 1;
+            wait_us(TRIG_PULSE_US);
+            _trig = 0;
+
+            if (_echo == 0) {
+                _state = STARTED;
+                timeout.attach_us(this, &Distance_HC_SR04::_tout, TIMEOUT_DELAY_US);
+
+                _echo.rise(this, &Distance_HC_SR04::_rising);
+                _echo.fall(this, &Distance_HC_SR04::_falling);
+
+                return;
+            }
+        }
+
+        if (_state == IDLE) {
+            _state = ERROR_SIG;
+            _ticks_us = 0;
+        }
+        
+        return;
+    }
+
+    Distance_HC_SR04_state getState(void) {
+        return _state;   
+    }
+    
+    void reset(void) {
+        _state = IDLE;
+        _echo.rise(NULL);
+        _echo.fall(NULL);
+        _timeout.detach();
+        _timer.stop();
+        _timer.reset();   
+    }
+    
+    uint32_t getTicks(void) {
+        return _ticks_us;
+    }
+    
+    float getDistance(void) {
+        return _ticks_us/_coeff;
+    }
+    
+    float getCoeff(void) {
+        return _coeff;
+    }
+    
+    void setCoeff(float coeff) {
+        _coeff = coeff;
+    }
+    
+    float measureDistance(void) {
+        return measureTicks()/_coeff;   
+    }
+    
+    uint32_t measureTicks(void) {
+        reset();
+        trigger();
+
+        while (_state == STARTED)
+            ;
+            
+        switch (_state) {
+            case COMPLETED:
+                break;
+            default:
+                break;
+        }
+                 
+        return _ticks_us;   
+    }
+
+
+
+    void _tout(void) {
+        if (_state == STARTED) 
+            _state = TIMEOUT;
+    }
+
+    void _rising(void) {
+        if (_state == STARTED) {
+            _timer.start();
+        }
+    }
+
+    void _falling(void) {
+        if (_state == STARTED) {
+            _timer.stop();
+            _ticks_us = _timer.read_us();
+            state = COMPLETED;
+        }
+    }
+ 
+private:
+    DigitalOut  _trig;
+    InterruptIn _echo;
+    uint32_t    _ticks_us;
+    uint32_t    _tout_us;
+    float       _coeff;
+    
+    Timer       _timer;
+    Timeout     _timeout;
+    
+    volatile Distance_HC_SR04_state _state;
+};
+ 
+
+
 int main() {
     
     trigDist = 0;