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121 lines
3.4 KiB
121 lines
3.4 KiB
/* |
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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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/* |
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* AP_RangeFinder_analog.cpp - rangefinder for analog source |
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* |
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*/ |
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#include <AP_HAL/AP_HAL.h> |
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#include <AP_Common/AP_Common.h> |
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#include <AP_Math/AP_Math.h> |
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#include "RangeFinder.h" |
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#include "AP_RangeFinder_Params.h" |
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#include "AP_RangeFinder_analog.h" |
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extern const AP_HAL::HAL& hal; |
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/* |
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The constructor also initialises the rangefinder. Note that this |
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constructor is not called until detect() returns true, so we |
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already know that we should setup the rangefinder |
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*/ |
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AP_RangeFinder_analog::AP_RangeFinder_analog(RangeFinder::RangeFinder_State &_state, AP_RangeFinder_Params &_params) : |
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AP_RangeFinder_Backend(_state, _params) |
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{ |
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source = hal.analogin->channel(_params.pin); |
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if (source == nullptr) { |
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// failed to allocate a ADC channel? This shouldn't happen |
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set_status(RangeFinder::RangeFinder_NotConnected); |
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return; |
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} |
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set_status(RangeFinder::RangeFinder_NoData); |
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} |
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/* |
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detect if an analog rangefinder is connected. The only thing we |
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can do is check if the pin number is valid. If it is, then assume |
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that the device is connected |
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*/ |
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bool AP_RangeFinder_analog::detect(AP_RangeFinder_Params &_params) |
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{ |
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if (_params.pin != -1) { |
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return true; |
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} |
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return false; |
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} |
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/* |
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update raw voltage state |
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*/ |
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void AP_RangeFinder_analog::update_voltage(void) |
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{ |
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if (source == nullptr) { |
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state.voltage_mv = 0; |
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return; |
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} |
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// cope with changed settings |
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source->set_pin(params.pin); |
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if (params.ratiometric) { |
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state.voltage_mv = source->voltage_average_ratiometric() * 1000U; |
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} else { |
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state.voltage_mv = source->voltage_average() * 1000U; |
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} |
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} |
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/* |
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update distance_cm |
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*/ |
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void AP_RangeFinder_analog::update(void) |
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{ |
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update_voltage(); |
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float v = state.voltage_mv * 0.001f; |
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float dist_m = 0; |
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float scaling = params.scaling; |
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float offset = params.offset; |
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RangeFinder::RangeFinder_Function function = (RangeFinder::RangeFinder_Function)params.function.get(); |
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int16_t _max_distance_cm = params.max_distance_cm; |
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switch (function) { |
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case RangeFinder::FUNCTION_LINEAR: |
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dist_m = (v - offset) * scaling; |
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break; |
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case RangeFinder::FUNCTION_INVERTED: |
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dist_m = (offset - v) * scaling; |
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break; |
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case RangeFinder::FUNCTION_HYPERBOLA: |
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if (v <= offset) { |
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dist_m = 0; |
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} else { |
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dist_m = scaling / (v - offset); |
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} |
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if (dist_m > _max_distance_cm * 0.01f) { |
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dist_m = _max_distance_cm * 0.01f; |
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} |
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break; |
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} |
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if (dist_m < 0) { |
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dist_m = 0; |
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} |
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state.distance_cm = dist_m * 100.0f; |
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state.last_reading_ms = AP_HAL::millis(); |
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// update range_valid state based on distance measured |
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update_status(); |
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} |
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