mirror of https://github.com/ArduPilot/ardupilot
344 lines
8.3 KiB
C++
344 lines
8.3 KiB
C++
/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "AP_Baro_BMP085.h"
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#include <utility>
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#include <stdio.h>
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#include <AP_Common/AP_Common.h>
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#include <AP_HAL/AP_HAL.h>
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extern const AP_HAL::HAL &hal;
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#define BMP085_OVERSAMPLING_ULTRALOWPOWER 0
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#define BMP085_OVERSAMPLING_STANDARD 1
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#define BMP085_OVERSAMPLING_HIGHRES 2
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#define BMP085_OVERSAMPLING_ULTRAHIGHRES 3
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#ifndef BMP085_EOC
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#define BMP085_EOC -1
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#define OVERSAMPLING BMP085_OVERSAMPLING_ULTRAHIGHRES
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#else
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#define OVERSAMPLING BMP085_OVERSAMPLING_HIGHRES
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#endif
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AP_Baro_BMP085::AP_Baro_BMP085(AP_Baro &baro, AP_HAL::OwnPtr<AP_HAL::Device> dev)
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: AP_Baro_Backend(baro)
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, _dev(std::move(dev))
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{ }
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AP_Baro_Backend * AP_Baro_BMP085::probe(AP_Baro &baro, AP_HAL::OwnPtr<AP_HAL::Device> dev)
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{
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if (!dev) {
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return nullptr;
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}
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AP_Baro_BMP085 *sensor = new AP_Baro_BMP085(baro, std::move(dev));
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if (!sensor || !sensor->_init()) {
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delete sensor;
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return nullptr;
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}
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return sensor;
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}
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bool AP_Baro_BMP085::_init()
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{
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union {
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uint8_t buff[22];
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uint16_t wb[11];
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} bb;
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// get pointer to i2c bus semaphore
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AP_HAL::Semaphore *sem = _dev->get_semaphore();
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// take i2c bus sempahore
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WITH_SEMAPHORE(sem);
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if (BMP085_EOC >= 0) {
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_eoc = hal.gpio->channel(BMP085_EOC);
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_eoc->mode(HAL_GPIO_INPUT);
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}
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uint8_t id;
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if (!_dev->read_registers(0xD0, &id, 1)) {
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return false;
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}
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if (id!=0x55) {
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return false; // not BMP180
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}
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_dev->read_registers(0xD1, &_vers, 1);
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bool prom_ok=false;
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_type=0;
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// We read the calibration data registers
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if (_dev->read_registers(0xAA, bb.buff, sizeof(bb.buff))) {
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prom_ok=true;
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}
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if (!prom_ok) {
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if (_read_prom((uint16_t *)&bb.wb[0])) { // BMP180 requires reads by 2 bytes
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prom_ok=true;
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_type=1;
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}
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}
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if (!prom_ok) {
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return false;
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}
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ac1 = ((int16_t)bb.buff[0] << 8) | bb.buff[1];
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ac2 = ((int16_t)bb.buff[2] << 8) | bb.buff[3];
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ac3 = ((int16_t)bb.buff[4] << 8) | bb.buff[5];
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ac4 = ((int16_t)bb.buff[6] << 8) | bb.buff[7];
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ac5 = ((int16_t)bb.buff[8] << 8) | bb.buff[9];
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ac6 = ((int16_t)bb.buff[10]<< 8) | bb.buff[11];
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b1 = ((int16_t)bb.buff[12] << 8) | bb.buff[13];
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b2 = ((int16_t)bb.buff[14] << 8) | bb.buff[15];
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mb = ((int16_t)bb.buff[16] << 8) | bb.buff[17];
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mc = ((int16_t)bb.buff[18] << 8) | bb.buff[19];
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md = ((int16_t)bb.buff[20] << 8) | bb.buff[21];
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if ((ac1==0 || ac1==-1) ||
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(ac2==0 || ac2==-1) ||
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(ac3==0 || ac3==-1) ||
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(ac4==0 || ac4==0xFFFF) ||
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(ac5==0 || ac5==0xFFFF) ||
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(ac6==0 || ac6==0xFFFF)) {
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return false;
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}
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_last_press_read_command_time = 0;
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_last_temp_read_command_time = 0;
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// Send a command to read temperature
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_cmd_read_temp();
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_state = 0;
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_instance = _frontend.register_sensor();
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_dev->register_periodic_callback(20000, FUNCTOR_BIND_MEMBER(&AP_Baro_BMP085::_timer, void));
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return true;
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}
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uint16_t AP_Baro_BMP085::_read_prom_word(uint8_t word)
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{
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const uint8_t reg = 0xAA + (word << 1);
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uint8_t val[2];
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if (!_dev->transfer(®, 1, val, sizeof(val))) {
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return 0;
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}
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return (val[0] << 8) | val[1];
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}
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bool AP_Baro_BMP085::_read_prom(uint16_t *prom)
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{
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bool all_zero = true;
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for (uint8_t i = 0; i < 11; i++) {
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prom[i] = _read_prom_word(i);
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if (prom[i] != 0) {
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all_zero = false;
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}
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}
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if (all_zero) {
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return false;
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}
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return true;
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}
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/*
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This is a state machine. Acumulate a new sensor reading.
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*/
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void AP_Baro_BMP085::_timer(void)
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{
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if (!_data_ready()) {
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return;
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}
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if (_state == 0) {
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_read_temp();
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} else if (_read_pressure()) {
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_calculate();
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}
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_state++;
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if (_state == 25) {
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_state = 0;
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_cmd_read_temp();
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} else {
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_cmd_read_pressure();
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}
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}
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/*
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transfer data to the frontend
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*/
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void AP_Baro_BMP085::update(void)
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{
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WITH_SEMAPHORE(_sem);
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if (!_has_sample) {
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return;
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}
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float temperature = 0.1f * _temp;
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float pressure = _pressure_filter.getf();
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_copy_to_frontend(_instance, pressure, temperature);
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}
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// Send command to Read Pressure
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void AP_Baro_BMP085::_cmd_read_pressure()
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{
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_dev->write_register(0xF4, 0x34 + (OVERSAMPLING << 6));
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_last_press_read_command_time = AP_HAL::millis();
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}
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// Read raw pressure values
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bool AP_Baro_BMP085::_read_pressure()
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{
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uint8_t buf[3];
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if (_dev->read_registers(0xF6, buf, sizeof(buf))) {
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_raw_pressure = (((uint32_t)buf[0] << 16)
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| ((uint32_t)buf[1] << 8)
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| ((uint32_t)buf[2])) >> (8 - OVERSAMPLING);
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return true;
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}
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uint8_t xlsb;
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if (_dev->read_registers(0xF6, buf, 2) && _dev->read_registers(0xF8, &xlsb, 1)) {
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_raw_pressure = (((uint32_t)buf[0] << 16)
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| ((uint32_t)buf[1] << 8)
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| ((uint32_t)xlsb)) >> (8 - OVERSAMPLING);
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return true;
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}
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_last_press_read_command_time = AP_HAL::millis() + 1000;
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_dev->set_speed(AP_HAL::Device::SPEED_LOW);
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return false;
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}
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// Send Command to Read Temperature
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void AP_Baro_BMP085::_cmd_read_temp()
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{
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_dev->write_register(0xF4, 0x2E);
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_last_temp_read_command_time = AP_HAL::millis();
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}
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// Read raw temperature values
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void AP_Baro_BMP085::_read_temp()
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{
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uint8_t buf[2];
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int32_t _temp_sensor;
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if (!_dev->read_registers(0xF6, buf, sizeof(buf))) {
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_dev->set_speed(AP_HAL::Device::SPEED_LOW);
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return;
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}
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_temp_sensor = buf[0];
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_temp_sensor = (_temp_sensor << 8) | buf[1];
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_raw_temp = _temp_sensor;
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}
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// _calculate Temperature and Pressure in real units.
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void AP_Baro_BMP085::_calculate()
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{
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int32_t x1, x2, x3, b3, b5, b6, p;
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uint32_t b4, b7;
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int32_t tmp;
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// See Datasheet page 13 for this formulas
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// Based also on Jee Labs BMP085 example code. Thanks for share.
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// Temperature calculations
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x1 = ((int32_t)_raw_temp - ac6) * ac5 >> 15;
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x2 = ((int32_t) mc << 11) / (x1 + md);
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b5 = x1 + x2;
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_temp = (b5 + 8) >> 4;
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// Pressure calculations
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b6 = b5 - 4000;
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x1 = (b2 * (b6 * b6 >> 12)) >> 11;
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x2 = ac2 * b6 >> 11;
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x3 = x1 + x2;
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//b3 = (((int32_t) ac1 * 4 + x3)<<OVERSAMPLING + 2) >> 2; // BAD
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//b3 = ((int32_t) ac1 * 4 + x3 + 2) >> 2; //OK for OVERSAMPLING=0
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tmp = ac1;
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tmp = (tmp*4 + x3)<<OVERSAMPLING;
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b3 = (tmp+2)/4;
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x1 = ac3 * b6 >> 13;
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x2 = (b1 * (b6 * b6 >> 12)) >> 16;
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x3 = ((x1 + x2) + 2) >> 2;
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b4 = (ac4 * (uint32_t)(x3 + 32768)) >> 15;
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b7 = ((uint32_t) _raw_pressure - b3) * (50000 >> OVERSAMPLING);
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p = b7 < 0x80000000 ? (b7 * 2) / b4 : (b7 / b4) * 2;
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x1 = (p >> 8) * (p >> 8);
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x1 = (x1 * 3038) >> 16;
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x2 = (-7357 * p) >> 16;
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p += ((x1 + x2 + 3791) >> 4);
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if (!pressure_ok(p)) {
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return;
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}
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WITH_SEMAPHORE(_sem);
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_pressure_filter.apply(p);
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_has_sample = true;
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}
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bool AP_Baro_BMP085::_data_ready()
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{
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if (BMP085_EOC >= 0) {
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return _eoc->read();
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}
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// No EOC pin: use time from last read instead.
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if (_state == 0) {
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return AP_HAL::millis() > _last_temp_read_command_time + 5;
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}
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uint32_t conversion_time_msec;
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switch (OVERSAMPLING) {
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case BMP085_OVERSAMPLING_ULTRALOWPOWER:
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conversion_time_msec = 5;
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break;
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case BMP085_OVERSAMPLING_STANDARD:
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conversion_time_msec = 8;
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break;
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case BMP085_OVERSAMPLING_HIGHRES:
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conversion_time_msec = 14;
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break;
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case BMP085_OVERSAMPLING_ULTRAHIGHRES:
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conversion_time_msec = 26;
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default:
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break;
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}
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return AP_HAL::millis() > _last_press_read_command_time + conversion_time_msec;
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}
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