Peter Barker
7 years ago
committed by
Andrew Tridgell
4 changed files with 206 additions and 11 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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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_RangeFinder_PWM.h" |
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#include <AP_HAL/AP_HAL.h> |
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#include <GCS_MAVLink/GCS.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. |
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*/ |
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AP_RangeFinder_PWM::AP_RangeFinder_PWM(RangeFinder::RangeFinder_State &_state) : |
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AP_RangeFinder_Backend(_state) |
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{ |
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} |
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/*
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There's no sensible way of detecting a PWM rangefinder as the pins are configurable |
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*/ |
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bool AP_RangeFinder_PWM::detect() |
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{ |
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return true; |
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} |
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// interrupt handler for reading pwm value
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void AP_RangeFinder_PWM::irq_handler(uint8_t pin, bool pin_high, uint32_t timestamp_us) |
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{ |
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if (pin_high) { |
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irq_pulse_start_us = timestamp_us; |
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} else { |
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if (irq_pulse_start_us != 0) { |
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irq_value_us = timestamp_us - irq_pulse_start_us; |
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irq_pulse_start_us = 0; |
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} |
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} |
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} |
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// read - return last value measured by sensor
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bool AP_RangeFinder_PWM::get_reading(uint16_t &reading_cm) |
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{ |
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// disable interrupts and grab state
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void *irqstate = hal.scheduler->disable_interrupts_save(); |
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const uint32_t value_us = irq_value_us; |
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irq_value_us = 0; |
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hal.scheduler->restore_interrupts(irqstate); |
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if (value_us == 0) { |
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return false; |
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} |
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reading_cm = value_us * 1e-1f; // correct for LidarLite. Parameter needed?
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return true; |
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} |
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void AP_RangeFinder_PWM::check_pin() |
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{ |
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if (state.pin == last_pin) { |
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return; |
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} |
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// detach last one
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if (last_pin > 0) { |
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if (!hal.gpio->detach_interrupt(last_pin)) { |
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gcs().send_text(MAV_SEVERITY_WARNING, |
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"RangeFinder_PWM: Failed to detach from pin %u", |
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last_pin); |
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// ignore this failure or the user may be stuck
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} |
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} |
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// set last pin to state.pin so we don't continually try to attach
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// to it if the attach is failing
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last_pin = state.pin; |
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if (state.pin <= 0) { |
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// don't need to install handler
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return; |
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} |
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// install interrupt handler on rising and falling edge
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if (!hal.gpio->attach_interrupt( |
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state.pin, |
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FUNCTOR_BIND_MEMBER(&AP_RangeFinder_PWM::irq_handler, |
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void, |
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uint8_t, |
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bool, |
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uint32_t), |
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AP_HAL::GPIO::INTERRUPT_BOTH)) { |
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// failed to attach interrupt
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gcs().send_text(MAV_SEVERITY_WARNING, |
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"RangeFinder_PWM: Failed to attach to pin %u", |
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state.pin); |
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return; |
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} |
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} |
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/*
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update the state of the sensor |
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*/ |
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void AP_RangeFinder_PWM::update(void) |
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{ |
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// check if pin has changed and configure interrupt handlers if required:
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check_pin(); |
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if (last_pin <= 0) { |
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// disabled (by configuration)
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return; |
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} |
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if (!get_reading(state.distance_cm)) { |
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// failure; consider changing our state
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if (AP_HAL::millis() - state.last_reading_ms > 200) { |
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set_status(RangeFinder::RangeFinder_NoData); |
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} |
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return; |
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} |
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// update range_valid state based on distance measured
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state.last_reading_ms = AP_HAL::millis(); |
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update_status(); |
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} |
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@ -0,0 +1,56 @@ |
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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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#pragma once |
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#include "RangeFinder.h" |
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#include "RangeFinder_Backend.h" |
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class AP_RangeFinder_PWM : public AP_RangeFinder_Backend |
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{ |
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public: |
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// constructor
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AP_RangeFinder_PWM(RangeFinder::RangeFinder_State &_state); |
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// destructor
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~AP_RangeFinder_PWM(void) {}; |
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// static detection function
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static bool detect(); |
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// update state
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void update(void); |
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protected: |
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bool get_reading(uint16_t &reading_cm); |
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MAV_DISTANCE_SENSOR _get_mav_distance_sensor_type() const override { |
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return MAV_DISTANCE_SENSOR_UNKNOWN; |
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} |
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private: |
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int8_t last_pin; // last pin used for reading pwm (used to recognise change in pin assignment)
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uint32_t last_reading_ms; // system time of last read (used for health reporting)
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// the following two members are updated by the interrupt handler
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uint32_t irq_value_us; // last calculated pwm value (irq copy)
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uint32_t irq_pulse_start_us; // system time of start of pulse
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void irq_handler(uint8_t pin, bool pin_high, uint32_t timestamp_us); |
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void check_pin(); |
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}; |
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