ardupilot/libraries/AP_Airspeed/AP_Airspeed_analog.cpp

48 lines
1.4 KiB
C++

/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
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 3 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, see <http://www.gnu.org/licenses/>.
*/
/*
* analog airspeed driver
*/
#include "AP_Airspeed_analog.h"
#include <AP_ADC/AP_ADC.h>
#include <AP_Common/AP_Common.h>
#include <AP_HAL/AP_HAL.h>
#include "AP_Airspeed.h"
extern const AP_HAL::HAL &hal;
// scaling for 3DR analog airspeed sensor
#define VOLTS_TO_PASCAL 819
bool AP_Airspeed_Analog::init()
{
_source = hal.analogin->channel(_pin);
return true;
}
// read the airspeed sensor
bool AP_Airspeed_Analog::get_differential_pressure(float &pressure)
{
if (_source == NULL) {
return false;
}
_source->set_pin(_pin);
pressure = _source->voltage_average_ratiometric() * VOLTS_TO_PASCAL / _psi_range.get();
return true;
}