ardupilot/libraries/AP_Airspeed/AP_Airspeed_ASP5033.cpp

174 lines
4.5 KiB
C++

/*
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 sensor from www.qio-tek.com
I2C ASP5033 sensor
*/
#include "AP_Airspeed_ASP5033.h"
#include <AP_HAL/I2CDevice.h>
extern const AP_HAL::HAL &hal;
#define ASP5033_I2C_ADDR_1 0x6C
#define ASP5033_I2C_ADDR_2 0x6D
#define REG_CMD 0x30
#define REG_PRESS_DATA 0x06
#define REG_TEMP_DATA 0x09
#define REG_PART_ID 0x01
#define REG_PART_ID_SET 0xa4
#define REG_SENSOR_READY 0x08
#define REG_WHOAMI_DEFAULT_ID 0X00
#define REG_WHOAMI_RECHECK_ID 0X66
#define CMD_MEASURE 0x0A
bool AP_Airspeed_ASP5033::init()
{
// probe the sensor, supporting multiple possible I2C addresses
const uint8_t addresses[] = { ASP5033_I2C_ADDR_1, ASP5033_I2C_ADDR_2 };
for (uint8_t address : addresses) {
dev = hal.i2c_mgr->get_device(get_bus(), address);
if (!dev) {
continue;
}
WITH_SEMAPHORE(dev->get_semaphore());
dev->set_speed(AP_HAL::Device::SPEED_HIGH);
dev->set_retries(2);
if (!confirm_sensor_id()) {
continue;
}
dev->register_periodic_callback(1000000UL/80U,
FUNCTOR_BIND_MEMBER(&AP_Airspeed_ASP5033::timer, void));
return true;
}
// not found
return false;
}
/*
this sensor has an unusual whoami scheme. The part_id is changeable
via another register. We check the sensor by looking for the
expected behaviour
*/
bool AP_Airspeed_ASP5033::confirm_sensor_id(void)
{
uint8_t part_id;
if (!dev->read_registers(REG_PART_ID_SET, &part_id, 1) ||
part_id != REG_WHOAMI_DEFAULT_ID) {
return false;
}
if (!dev->write_register(REG_PART_ID_SET, REG_WHOAMI_RECHECK_ID)) {
return false;
}
if (!dev->read_registers(REG_PART_ID, &part_id, 1) ||
part_id != REG_WHOAMI_RECHECK_ID) {
return false;
}
return true;
}
// read the data from the sensor
void AP_Airspeed_ASP5033::timer()
{
// request a new measurement cycle begin
dev->write_register(REG_CMD, CMD_MEASURE);
uint8_t status;
if (!dev->read_registers(REG_CMD, &status, 1) ||
(status & REG_SENSOR_READY) == 0) {
// no data ready
return;
}
// read pressure and temperature as one block
uint8_t data[5];
if (!dev->read_registers(REG_PRESS_DATA, data, sizeof(data))) {
return;
}
// ADC pressure is signed 24 bit
int32_t press = (data[0]<<24) | (data[1]<<16) | (data[2]<<8);
// convert back to 24 bit
press >>= 8;
// k is a shift based on the pressure range of the device. See
// table in the datasheet
constexpr uint8_t k = 7;
constexpr float press_scale = 1.0 / (1U<<k);
// temperature is 16 bit signed in units of 1/256 C
const int16_t temp = (data[3]<<8) | data[4];
constexpr float temp_scale = 1.0 / 256;
WITH_SEMAPHORE(sem);
press_sum += press * press_scale;
temp_sum += temp * temp_scale;
press_count++;
temp_count++;
last_sample_ms = AP_HAL::millis();
}
// return the current differential_pressure in Pascal
bool AP_Airspeed_ASP5033::get_differential_pressure(float &pressure)
{
WITH_SEMAPHORE(sem);
if (AP_HAL::millis() - last_sample_ms > 100) {
return false;
}
if (press_count == 0) {
pressure = last_pressure;
return true;
}
last_pressure = pressure = press_sum / press_count;
press_count = 0;
press_sum = 0;
return true;
}
// return the current temperature in degrees C, if available
bool AP_Airspeed_ASP5033::get_temperature(float &temperature)
{
WITH_SEMAPHORE(sem);
if (AP_HAL::millis() - last_sample_ms > 100) {
return false;
}
if (temp_count == 0) {
temperature = last_temperature;
return true;
}
last_temperature = temperature = temp_sum / temp_count;
temp_count = 0;
temp_sum = 0;
return true;
}