mirror of https://github.com/ArduPilot/ardupilot
117 lines
2.9 KiB
C++
117 lines
2.9 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/>.
|
|
*/
|
|
|
|
/*
|
|
backend driver for airspeed from a I2C MS4525D0 sensor
|
|
*/
|
|
|
|
#include <AP_Common.h>
|
|
#include <AP_HAL.h>
|
|
#include <AP_Math.h>
|
|
#include <AP_Airspeed_I2C.h>
|
|
|
|
extern const AP_HAL::HAL& hal;
|
|
|
|
#define I2C_ADDRESS_MS4525DO 0x28
|
|
|
|
// probe and initialise the sensor
|
|
bool AP_Airspeed_I2C::init(void)
|
|
{
|
|
_measure();
|
|
hal.scheduler->delay(10);
|
|
_collect();
|
|
if (_last_sample_time_ms != 0) {
|
|
hal.scheduler->register_timer_process(AP_HAL_MEMBERPROC(&AP_Airspeed_I2C::_timer));
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// start a measurement
|
|
void AP_Airspeed_I2C::_measure(void)
|
|
{
|
|
_measurement_started_ms = 0;
|
|
if (hal.i2c->writeRegisters(I2C_ADDRESS_MS4525DO, 0, 0, NULL) != 0) {
|
|
return;
|
|
}
|
|
_measurement_started_ms = hal.scheduler->millis();
|
|
}
|
|
|
|
// read the values from the sensor
|
|
void AP_Airspeed_I2C::_collect(void)
|
|
{
|
|
uint8_t data[4];
|
|
_measurement_started_ms = 0;
|
|
|
|
if (hal.i2c->read(I2C_ADDRESS_MS4525DO, 4, data) != 0) {
|
|
return;
|
|
}
|
|
|
|
uint8_t status = data[0] & 0xC0;
|
|
if (status == 2) {
|
|
return;
|
|
} else if (status == 3) {
|
|
return;
|
|
}
|
|
|
|
int16_t dp_raw, dT_raw;
|
|
dp_raw = (data[0] << 8) + data[1];
|
|
dp_raw = 0x3FFF & dp_raw;
|
|
dT_raw = (data[2] << 8) + data[3];
|
|
dT_raw = (0xFFE0 & dT_raw) >> 5;
|
|
|
|
_temperature = ((200 * dT_raw) / 2047) - 50;
|
|
_pressure = fabs(dp_raw - (16384 / 2.0f));
|
|
_last_sample_time_ms = hal.scheduler->millis();
|
|
}
|
|
|
|
// 1kHz timer
|
|
void AP_Airspeed_I2C::_timer(void)
|
|
{
|
|
if (_measurement_started_ms == 0) {
|
|
_measure();
|
|
return;
|
|
}
|
|
if ((hal.scheduler->millis() - _measurement_started_ms) > 10) {
|
|
_collect();
|
|
// start a new measurement
|
|
_measure();
|
|
}
|
|
}
|
|
|
|
// return the current differential_pressure in Pascal
|
|
bool AP_Airspeed_I2C::get_differential_pressure(float &pressure)
|
|
{
|
|
if ((hal.scheduler->millis() - _last_sample_time_ms) > 100) {
|
|
return false;
|
|
}
|
|
pressure = _pressure;
|
|
return true;
|
|
}
|
|
|
|
// return the current temperature in degrees C, if available
|
|
bool AP_Airspeed_I2C::get_temperature(float &temperature)
|
|
{
|
|
if ((hal.scheduler->millis() - _last_sample_time_ms) > 100) {
|
|
return false;
|
|
}
|
|
temperature = _temperature;
|
|
return true;
|
|
}
|
|
|
|
|