// ucoolib - Microcontroller object oriented library. {{{ // // Copyright (C) 2013 Nicolas Schodet // // APBTeam: // Web: http://apbteam.org/ // Email: team AT apbteam DOT org // // This program is free software; you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation; either version 2 of the License, or // (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. // // }}} #include "usdist.hh" namespace ucoo { UsDist::UsDist (UsDistControl &ctrl, Adc &adc, Io &io, int distance_min, int distance_max, int distance_too_far) : adc_ (adc), io_ (io), next_ (0), distance_min_ (distance_min), distance_max_ (distance_max), distance_too_far_ (distance_too_far), distance_ (-1) { next_ = ctrl.sensors_; ctrl.sensors_ = this; } void UsDist::enable () { io_.set (); } void UsDist::disable () { io_.reset (); } int UsDist::read () { int v = adc_.read (); // The sensor returns a value between 4 and 20 mA proportional to the // distance between calibrated values. Ignore faulty sensors. const int max = adc_.get_resolution (); const int min = max / 5; if (v <= min / 4) distance_ = -1; else if (v <= min) distance_ = distance_min_; else distance_ = distance_min_ + ((v - min) * (distance_max_ - distance_min_) / (max - min)); if (distance_too_far_ != -1 && distance_ > distance_too_far_) distance_ = -1; return distance_; } UsDistControl::UsDistControl (int period) : period_ (period), sensors_ (0), current_ (0), wait_ (0) { } bool UsDistControl::update () { bool new_measure = false; if (wait_) wait_--; else { if (current_) { current_->disable (); current_->read (); new_measure = true; current_ = current_->next_; } if (!current_) current_ = sensors_; current_->enable (); wait_ = period_ - 1; } return new_measure; } } // namespace ucoo