mirror of https://github.com/ArduPilot/ardupilot
126 lines
3.6 KiB
C++
126 lines
3.6 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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/*
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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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source->set_stop_pin((uint8_t)_params.stop_pin);
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source->set_settle_time((uint16_t)_params.settle_time_ms);
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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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source->set_stop_pin((uint8_t)params.stop_pin);
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source->set_settle_time((uint16_t)params.settle_time_ms);
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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 (isinf(dist_m) || 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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