Pulse measurement to know signal occupancy
Diff: PwmReader.cpp
- Revision:
- 1:ebc39fb22351
- Parent:
- 0:15aa9d3aeb2e
--- 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