mirror of https://github.com/ArduPilot/ardupilot
129 lines
3.9 KiB
C++
129 lines
3.9 KiB
C++
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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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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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_PulsedLightLRF.cpp - Arduino Library for Pulsed Light's Laser Range Finder
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* Code by Randy Mackay. DIYDrones.com
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*
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* Sensor should be connected to the I2C port
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*
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* Variables:
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* bool healthy : indicates whether last communication with sensor was successful
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*
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* Methods:
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* take_reading(): ask the sonar to take a new distance measurement
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* read() : read last distance measured (in cm)
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*
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*/
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#include "AP_RangeFinder_PulsedLightLRF.h"
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#include <AP_HAL.h>
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extern const AP_HAL::HAL& hal;
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// Constructor //////////////////////////////////////////////////////////////
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AP_RangeFinder_PulsedLightLRF::AP_RangeFinder_PulsedLightLRF(FilterInt16 *filter) :
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RangeFinder(NULL, filter),
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healthy(true),
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_addr(AP_RANGEFINDER_PULSEDLIGHTLRF_ADDR)
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{
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min_distance = AP_RANGEFINDER_PULSEDLIGHTLRF_MIN_DISTANCE;
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max_distance = AP_RANGEFINDER_PULSEDLIGHTLRF_MAX_DISTANCE;
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}
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// Public Methods //////////////////////////////////////////////////////////////
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// init - simply sets the i2c address
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void AP_RangeFinder_PulsedLightLRF::init(uint8_t address)
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{
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// set sensor i2c address
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_addr = address;
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}
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// take_reading - ask sensor to make a range reading
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bool AP_RangeFinder_PulsedLightLRF::take_reading()
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{
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// get pointer to i2c bus semaphore
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AP_HAL::Semaphore* i2c_sem = hal.i2c->get_semaphore();
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// exit immediately if we can't take the semaphore
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if (i2c_sem == NULL || !i2c_sem->take(5)) {
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healthy = false;
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return healthy;
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}
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// send command to take reading
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if (hal.i2c->writeRegister(_addr, AP_RANGEFINDER_PULSEDLIGHTLRF_MEASURE_REG, AP_RANGEFINDER_PULSEDLIGHTLRF_MSRREG_ACQUIRE) != 0) {
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healthy = false;
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}else{
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healthy = true;
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}
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hal.scheduler->delay_microseconds(200);
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// return semaphore
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i2c_sem->give();
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return healthy;
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}
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// read - return last value measured by sensor
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int16_t AP_RangeFinder_PulsedLightLRF::read()
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{
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uint8_t buff[2];
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int16_t ret_value = 0;
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// get pointer to i2c bus semaphore
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AP_HAL::Semaphore* i2c_sem = hal.i2c->get_semaphore();
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// exit immediately if we can't take the semaphore
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if (i2c_sem == NULL || !i2c_sem->take(5)) {
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healthy = false;
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return healthy;
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}
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// assume the worst
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healthy = false;
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// read the high byte
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if (hal.i2c->readRegisters(_addr, AP_RANGEFINDER_PULSEDLIGHTLRF_DISTHIGH_REG, 1, &buff[0]) == 0) {
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hal.scheduler->delay_microseconds(200);
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// read the low byte
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if (hal.i2c->readRegisters(_addr, AP_RANGEFINDER_PULSEDLIGHTLRF_DISTLOW_REG, 1, &buff[1]) == 0) {
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healthy = true;
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// combine results into distance
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ret_value = buff[0] << 8 | buff[1];
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}
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}
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// ensure distance is within min and max
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ret_value = constrain_int16(ret_value, min_distance, max_distance);
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ret_value = _mode_filter->apply(ret_value);
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hal.scheduler->delay_microseconds(200);
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// return semaphore
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i2c_sem->give();
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// kick off another reading for next time
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// To-Do: replace this with continuous mode
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take_reading();
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// to-do: do we really want to return 0 if reading the distance fails?
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return ret_value;
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}
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