Revision 1:ebc39fb22351, committed 2017-01-26

Comitter:

abouillot

Date:

Thu Jan 26 08:26:22 2017 +0000

Parent:

0:15aa9d3aeb2e

Commit message:

Fixed few bugs and added inline documentation. It is now possible to retrieve the time spent in a state in us, ms and seconds.

Changed in this revision

diff -r 15aa9d3aeb2e -r ebc39fb22351 PwmReader.cpp
--- a/PwmReader.cpp	Wed Jan 25 08:52:00 2017 +0000
+++ b/PwmReader.cpp	Thu Jan 26 08:26:22 2017 +0000
@@ -23,51 +23,89 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
- 
+
 #include "PwmReader.h"
 
+/// #define TRACE to enable TRACEs using printf #undef to disable
+#undef TRACE
+
 
 void PwmReader::pressedInt()
 {
+    long now = _timer.read_us();
+    // signal moved from high to low, record the time spent in this state
     _high += _timer.read_us() - _last_toggle;
+    // record the new timestamp
     _last_toggle = _timer.read_us();
-//    _timer.reset();
-//    printf("p %ld ", _high);
+#ifdef TRACE
+    printf("p %ld ", _high);
+#endif
 //    sleep();
 }
 
 void PwmReader::releasedInt()
 {
-    _down += _timer.read_us() - _last_toggle;
-    _last_toggle = _timer.read_us();
-//    _timer.reset();
-//    printf("r %ld", _down);
+    long now = _timer.read_us();
+    // signal moved from down to high, record the time spent in this state
+    _down += now - _last_toggle;
+    // record the new timestamp
+    _last_toggle = now;
+#ifdef TRACE
+    printf("r %ld", _down);
+#endif
 //    sleep();
 }
 
 void PwmReader::init()
 {
+    // register the interupt attached with the levels changes
     _pin.fall(callback(this, &PwmReader::pressedInt));
     _pin.rise(callback(this, &PwmReader::releasedInt));
 }
 
 void PwmReader::start()
 {
+    // reset the storing variable
     _high = 0;
     _down = 0;
+    _last_toggle = 0;
+
+    // store the inital state
     _start_state = _pin.read();
+
+    // start the timer at 0
+    _timer.reset();
+    _timer.start();
+
+    // enable the IRQ requests
     _pin.enable_irq();
-    _timer.start();
+
+#ifdef TRACE
+    if (_pin.read() != _start_state) {
+        printf("toggle ");
+    }
+    if (_pin.read() == 0) {
+        printf("low ");
+    }
+    if (_pin.read() == 1) {
+        printf("high ");
+    }
+#endif
 }
 
 void PwmReader::stop()
 {
+    // disable the IRQ request, to avoid code call
     _pin.disable_irq();
 
+    // no time has been recorded. The signal stayed at the same level from the start of measurment
     if (_high == 0 && _down == 0)
-        if (_start_state == 0)
+        // retrieve the duration of the measurment to assign it to the right state
+        if (_start_state == 1)
             _high = _timer.read_us();
-        else if (_start_state == 1)
+        else if (_start_state == 0)
             _down = _timer.read_us();
+
+    // stop the running timer
     _timer.stop();
 }
\ No newline at end of file

diff -r 15aa9d3aeb2e -r ebc39fb22351 PwmReader.h
--- a/PwmReader.h	Wed Jan 25 08:52:00 2017 +0000
+++ b/PwmReader.h	Thu Jan 26 08:26:22 2017 +0000
@@ -23,29 +23,87 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
- 
- #include "mbed.h"
- 
+
+#include "mbed.h"
+
+/*!
+ * Class PwmReader lmeasure the time spend in high and low state on a digital pin
+ * Uses useconds timer and IRQ
+ */
 class PwmReader
 {
 public:
+    /** create a PwmReader object
+     *
+     *  @param pin Pin numer to be observed
+     */
     PwmReader(PinName pin) : _pin(pin) {
         init();
     };
+    /** Start the measurment
+     *
+     */
     void start();
+    /** Stop the measurment
+     *
+     */
     void stop();
+    /** return the time spend in low state
+     *
+     * @return the percentage of time spent in low state. value between 0.0 and 1.0
+     */
     float occupacyLow() {
         return 100.0 * _down / (_down + _high);
     };
+    /** return the time spend in high state
+     *
+     * @return the percentage of time spent in high state. value between 0.0 and 1.0
+     */
     float occupacyHigh() {
         return 100.0 * _high / (_down + _high);
     };
-    long down() {
+    /** return the time spend in low state
+      *
+     * @return the percentage of time spent in low state. value in useconds
+     */
+    long down_us() {
         return _down;
     };
-    float high() {
+    /** return the time spend in high state
+     *
+     * @return the percentage of time spent in high state. value in useconds
+     */
+    long high_us() {
         return _high;
     };
+    /** return the time spend in low state
+    * @param round set round to tue to round the value (closest integer) - false by default
+    * @return the time spent in low state. value in mseconds
+    */
+    long down_ms(bool round = false) {
+        return (_down + (round ? 500 : 0)) / 1000;
+    };
+    /** return the time spend in high state
+     * @param round set round to tue to round the value (closest integer) - false by default
+     * @return the time spent in high state. value in mseconds
+     */
+    long high_ms(bool round = false) {
+        return (_high + (round ? 500 : 0)) / 1000;
+    };
+    /** return the time spend in low state
+     * @param round set round to tue to round the value (closest integer) - false by default
+     * @return the time spent in low state. value in seconds
+     */
+    long down(bool round = false) {
+        return (_down + (round ? 500000 : 0)) / 1000000;
+    };
+    /** return the time spend in high state
+     * @param round set round to tue to round the value (closest integer) - false by default
+     * @return the time spent in high state. value in seconds
+     */
+    long high(bool round = false) {
+        return (_high + (round ? 500000 : 0)) / 1000000;
+    };
 private:
     void init();
     void pressedInt();