ardupilot/libraries/AP_Baro/AP_Baro_KellerLD.cpp

258 lines
7.9 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/>.
*/
#include "AP_Baro_KellerLD.h"
#include <utility>
#include <stdio.h>
#include <AP_Math/AP_Math.h>
#define KELLER_DEBUG 0
#if KELLER_DEBUG
# define Debug(fmt, args ...) do {printf(fmt "\n", ## args);} while(0)
#else
# define Debug(fmt, args ...)
#endif
extern const AP_HAL::HAL &hal;
// Measurement range registers
static const uint8_t CMD_PRANGE_MIN_MSB = 0x13;
static const uint8_t CMD_PRANGE_MIN_LSB = 0x14;
static const uint8_t CMD_PRANGE_MAX_MSB = 0x15;
static const uint8_t CMD_PRANGE_MAX_LSB = 0x16;
// write to this address to start pressure measurement
static const uint8_t CMD_REQUEST_MEASUREMENT = 0xAC;
AP_Baro_KellerLD::AP_Baro_KellerLD(AP_Baro &baro, AP_HAL::OwnPtr<AP_HAL::Device> dev)
: AP_Baro_Backend(baro)
, _dev(std::move(dev))
{
}
// Look for the device on the bus and see if it responds appropriately
AP_Baro_Backend *AP_Baro_KellerLD::probe(AP_Baro &baro, AP_HAL::OwnPtr<AP_HAL::Device> dev)
{
if (!dev) {
return nullptr;
}
AP_Baro_KellerLD *sensor = new AP_Baro_KellerLD(baro, std::move(dev));
if (!sensor || !sensor->_init()) {
delete sensor;
return nullptr;
}
return sensor;
}
// The hardware does not need to be reset/initialized
// We read out the measurement range to be used in raw value conversions
bool AP_Baro_KellerLD::_init()
{
if (!_dev) {
return false;
}
_dev->get_semaphore()->take_blocking();
// high retries for init
_dev->set_retries(10);
bool cal_read_ok = true;
uint8_t data[3];
uint16_t ms_word, ls_word;
// This device has some undocumented finicky quirks and requires delays when reading out the
// measurement range, but for some reason this isn't an issue when requesting measurements.
// This is why we need to split the transfers with delays like this.
// (Using AP_HAL::I2CDevice::set_split_transfers will not work with these sensors)
// Read out pressure measurement range
cal_read_ok &= _dev->transfer(&CMD_PRANGE_MIN_MSB, 1, nullptr, 0);
hal.scheduler->delay(1);
cal_read_ok &= _dev->transfer(nullptr, 0, &data[0], 3);
hal.scheduler->delay(1);
ms_word = (data[1] << 8) | data[2];
Debug("0x13: %d [%d, %d, %d]", ms_word, data[0], data[1], data[2]);
cal_read_ok &= _dev->transfer(&CMD_PRANGE_MIN_LSB, 1, nullptr, 0);
hal.scheduler->delay(1);
cal_read_ok &= _dev->transfer(nullptr, 0, &data[0], 3);
hal.scheduler->delay(1);
ls_word = (data[1] << 8) | data[2];
Debug("0x14: %d [%d, %d, %d]", ls_word, data[0], data[1], data[2]);
uint32_t cal_data = (ms_word << 16) | ls_word;
memcpy(&_p_min, &cal_data, sizeof(_p_min));
Debug("data: %d, p_min: %.2f", cal_data, _p_min);
cal_read_ok &= _dev->transfer(&CMD_PRANGE_MAX_MSB, 1, nullptr, 0);
hal.scheduler->delay(1);
cal_read_ok &= _dev->transfer(nullptr, 0, &data[0], 3);
hal.scheduler->delay(1);
ms_word = (data[1] << 8) | data[2];
Debug("0x15: %d [%d, %d, %d]", ms_word, data[0], data[1], data[2]);
cal_read_ok &= _dev->transfer(&CMD_PRANGE_MAX_LSB, 1, nullptr, 0);
hal.scheduler->delay(1);
cal_read_ok &= _dev->transfer(nullptr, 0, &data[0], 3);
hal.scheduler->delay(1);
ls_word = (data[1] << 8) | data[2];
Debug("0x16: %d [%d, %d, %d]", ls_word, data[0], data[1], data[2]);
cal_data = (ms_word << 16) | ls_word;
memcpy(&_p_max, &cal_data, sizeof(_p_max));
Debug("data: %d, p_max: %.2f", cal_data, _p_max);
cal_read_ok &= !isnan(_p_min) && !isinf(_p_min) && !isnan(_p_max) && !isinf(_p_max);
cal_read_ok &= _p_max > _p_min;
if (!cal_read_ok) {
printf("Cal read bad!\n");
_dev->get_semaphore()->give();
return false;
}
printf("Keller LD found on bus %u address 0x%02x\n", _dev->bus_num(), _dev->get_bus_address());
// Send a command to take a measurement
_dev->transfer(&CMD_REQUEST_MEASUREMENT, 1, nullptr, 0);
memset(&_accum, 0, sizeof(_accum));
_instance = _frontend.register_sensor();
_dev->set_device_type(DEVTYPE_BARO_KELLERLD);
set_bus_id(_instance, _dev->get_bus_id());
_frontend.set_type(_instance, AP_Baro::BARO_TYPE_WATER);
// lower retries for run
_dev->set_retries(3);
_dev->get_semaphore()->give();
// The sensor needs time to take a deep breath after reading out the calibration...
hal.scheduler->delay(150);
// Request 50Hz update
// The sensor really struggles with any jitter in timing at 100Hz, and will sometimes start reading out all zeros
_dev->register_periodic_callback(20 * AP_USEC_PER_MSEC,
FUNCTOR_BIND_MEMBER(&AP_Baro_KellerLD::_timer, void));
return true;
}
// Read out most recent measurement from sensor hw
bool AP_Baro_KellerLD::_read()
{
uint8_t data[5];
if (!_dev->transfer(nullptr, 1, data, sizeof(data))) {
Debug("Keller LD read failed!");
return false;
}
//uint8_t status = data[0];
uint16_t pressure_raw = (data[1] << 8) | data[2];
uint16_t temperature_raw = (data[3] << 8) | data[4];
#if KELLER_DEBUG
static uint8_t samples = 0;
if (samples < 3) {
samples++;
Debug("data: [%d, %d, %d, %d, %d]", data[0], data[1], data[2], data[3], data[4]);
Debug("pressure_raw: %d\ttemperature_raw: %d", pressure_raw, temperature_raw);
}
#endif
if (pressure_raw == 0 || temperature_raw == 0) {
Debug("Keller: bad read");
return false;
}
if (!pressure_ok(pressure_raw)) {
return false;
}
WITH_SEMAPHORE(_sem);
_update_and_wrap_accumulator(pressure_raw, temperature_raw, 128);
return true;
}
// Periodic callback, regular update at 50Hz
// Read out most recent measurement, and request another
// Max conversion time according to datasheet is ~8ms, so
// max update rate is ~125Hz, yet we struggle to get consistent
// performance/data at 100Hz
void AP_Baro_KellerLD::_timer(void)
{
_read();
_dev->transfer(&CMD_REQUEST_MEASUREMENT, 1, nullptr, 0);
}
// Accumulate a reading, shrink if necessary to prevent overflow
void AP_Baro_KellerLD::_update_and_wrap_accumulator(uint16_t pressure, uint16_t temperature, uint8_t max_count)
{
_accum.sum_pressure += pressure;
_accum.sum_temperature += temperature;
_accum.num_samples += 1;
if (_accum.num_samples == max_count) {
_accum.sum_pressure /= 2;
_accum.sum_temperature /= 2;
_accum.num_samples /= 2;
}
}
// Take the average of accumulated values and push to frontend
void AP_Baro_KellerLD::update()
{
float sum_pressure, sum_temperature;
float num_samples;
{
WITH_SEMAPHORE(_sem);
if (_accum.num_samples == 0) {
return;
}
sum_pressure = _accum.sum_pressure;
sum_temperature = _accum.sum_temperature;
num_samples = _accum.num_samples;
memset(&_accum, 0, sizeof(_accum));
}
uint16_t raw_pressure_avg = sum_pressure / num_samples;
uint16_t raw_temperature_avg = sum_temperature / num_samples;
// per datasheet
float pressure = (raw_pressure_avg - 16384) * (_p_max - _p_min) / 32768 + _p_min;
pressure *= 100000; // bar -> Pascal
pressure += 101300; // MSL pressure offset
float temperature = ((raw_temperature_avg >> 4) - 24) * 0.05f - 50;
_copy_to_frontend(_instance, pressure, temperature);
}