4 changed files with 228 additions and 2 deletions
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/*
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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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|
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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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|
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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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/*
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backend driver for airspeed sensor from www.qio-tek.com |
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I2C ASP5033 sensor |
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*/ |
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#include "AP_Airspeed_ASP5033.h" |
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#include <AP_HAL/I2CDevice.h> |
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extern const AP_HAL::HAL &hal; |
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#define ASP5033_I2C_ADDR_1 0x6C |
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#define ASP5033_I2C_ADDR_2 0x6D |
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#define REG_CMD 0x30 |
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#define REG_PRESS_DATA 0x06 |
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#define REG_TEMP_DATA 0x09 |
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#define REG_PART_ID 0x01 |
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#define REG_PART_ID_SET 0xa4 |
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#define REG_SENSOR_READY 0x08 |
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#define REG_WHOAMI_DEFAULT_ID 0X00 |
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#define REG_WHOAMI_RECHECK_ID 0X66 |
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#define CMD_MEASURE 0x0A |
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bool AP_Airspeed_ASP5033::init() |
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{ |
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// probe the sensor, supporting multiple possible I2C addresses
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const uint8_t addresses[] = { ASP5033_I2C_ADDR_1, ASP5033_I2C_ADDR_2 }; |
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for (uint8_t address : addresses) { |
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dev = hal.i2c_mgr->get_device(get_bus(), address); |
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if (!dev) { |
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continue; |
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} |
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WITH_SEMAPHORE(dev->get_semaphore()); |
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dev->set_speed(AP_HAL::Device::SPEED_HIGH); |
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dev->set_retries(2); |
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if (!confirm_sensor_id()) { |
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continue; |
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} |
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dev->register_periodic_callback(1000000UL/80U, |
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FUNCTOR_BIND_MEMBER(&AP_Airspeed_ASP5033::timer, void)); |
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return true; |
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} |
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// not found
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return false; |
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} |
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/*
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this sensor has an unusual whoami scheme. The part_id is changeable |
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via another register. We check the sensor by looking for the |
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expected behaviour |
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*/ |
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bool AP_Airspeed_ASP5033::confirm_sensor_id(void) |
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{ |
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uint8_t part_id; |
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if (!dev->read_registers(REG_PART_ID_SET, &part_id, 1) || |
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part_id != REG_WHOAMI_DEFAULT_ID) { |
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return false; |
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} |
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if (!dev->write_register(REG_PART_ID_SET, REG_WHOAMI_RECHECK_ID)) { |
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return false; |
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} |
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if (!dev->read_registers(REG_PART_ID, &part_id, 1) || |
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part_id != REG_WHOAMI_RECHECK_ID) { |
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return false; |
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} |
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return true; |
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} |
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// read the data from the sensor
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void AP_Airspeed_ASP5033::timer() |
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{ |
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// request a new measurement cycle begin
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dev->write_register(REG_CMD, CMD_MEASURE); |
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uint8_t status; |
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if (!dev->read_registers(REG_CMD, &status, 1) || |
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(status & REG_SENSOR_READY) == 0) { |
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// no data ready
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return; |
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} |
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// read pressure and temperature as one block
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uint8_t data[5]; |
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if (!dev->read_registers(REG_PRESS_DATA, data, sizeof(data))) { |
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return; |
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} |
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// ADC pressure is signed 24 bit
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int32_t press = (data[0]<<24) | (data[1]<<16) | (data[2]<<8); |
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// convert back to 24 bit
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press >>= 8; |
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// k is a shift based on the pressure range of the device. See
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// table in the datasheet
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constexpr uint8_t k = 7; |
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constexpr float press_scale = 1.0 / (1U<<k); |
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// temperature is 16 bit signed in units of 1/256 C
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const int16_t temp = (data[3]<<8) | data[4]; |
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constexpr float temp_scale = 1.0 / 256; |
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WITH_SEMAPHORE(sem); |
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press_sum += press * press_scale; |
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temp_sum += temp * temp_scale; |
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press_count++; |
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temp_count++; |
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last_sample_ms = AP_HAL::millis(); |
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} |
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// return the current differential_pressure in Pascal
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bool AP_Airspeed_ASP5033::get_differential_pressure(float &pressure) |
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{ |
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WITH_SEMAPHORE(sem); |
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if (AP_HAL::millis() - last_sample_ms > 100) { |
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return false; |
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} |
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if (press_count == 0) { |
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pressure = last_pressure; |
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return true; |
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} |
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last_pressure = pressure = press_sum / press_count; |
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press_count = 0; |
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press_sum = 0; |
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return true; |
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} |
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// return the current temperature in degrees C, if available
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bool AP_Airspeed_ASP5033::get_temperature(float &temperature) |
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{ |
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WITH_SEMAPHORE(sem); |
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if (AP_HAL::millis() - last_sample_ms > 100) { |
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return false; |
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} |
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if (temp_count == 0) { |
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temperature = last_temperature; |
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return true; |
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} |
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last_temperature = temperature = temp_sum / temp_count; |
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temp_count = 0; |
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temp_sum = 0; |
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return true; |
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} |
@ -0,0 +1,46 @@
@@ -0,0 +1,46 @@
|
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/*
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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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|
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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 |
||||
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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#pragma once |
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/*
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backend driver for airspeed from I2C |
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*/ |
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#include "AP_Airspeed_Backend.h" |
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class AP_Airspeed_ASP5033 : public AP_Airspeed_Backend |
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{ |
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public: |
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using AP_Airspeed_Backend::AP_Airspeed_Backend; |
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bool init() override; |
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// return the current differential_pressure in Pascal
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bool get_differential_pressure(float &_pressure) override; |
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// return the current temperature in degrees C, if available
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bool get_temperature(float &_temperature) override; |
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private: |
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void timer(); |
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bool confirm_sensor_id(void); |
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float temp_sum; |
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float press_sum; |
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float last_pressure; |
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float last_temperature; |
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uint32_t press_count; |
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uint32_t temp_count; |
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uint32_t last_sample_ms; |
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AP_HAL::OwnPtr<AP_HAL::I2CDevice> dev; |
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}; |
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