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100 lines
2.6 KiB
100 lines
2.6 KiB
// -*- 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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#include <AP_HAL/AP_HAL.h> |
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#if CONFIG_HAL_BOARD == HAL_BOARD_PX4 || CONFIG_HAL_BOARD == HAL_BOARD_VRBRAIN |
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#include "RPM_PX4_PWM.h" |
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#include <sys/types.h> |
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#include <sys/stat.h> |
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#include <fcntl.h> |
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#include <unistd.h> |
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#include <drivers/drv_pwm_input.h> |
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#include <drivers/drv_hrt.h> |
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#include <drivers/drv_sensor.h> |
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#include <uORB/topics/pwm_input.h> |
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#include <stdio.h> |
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#include <errno.h> |
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#include <math.h> |
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extern const AP_HAL::HAL& hal; |
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/* |
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don't accept periods below 100us as it is probably ringing of the |
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signal. It would represent 600k RPM |
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*/ |
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#define RPM_MIN_PERIOD_US 100 |
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/* |
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open the sensor in constructor |
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*/ |
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AP_RPM_PX4_PWM::AP_RPM_PX4_PWM(AP_RPM &_ap_rpm, uint8_t instance, AP_RPM::RPM_State &_state) : |
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AP_RPM_Backend(_ap_rpm, instance, _state) |
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{ |
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_fd = open(PWMIN0_DEVICE_PATH, O_RDONLY); |
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if (_fd == -1) { |
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hal.console->printf("Unable to open %s\n", PWMIN0_DEVICE_PATH); |
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return; |
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} |
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// keep a queue of 5 samples to reduce noise by averaging |
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if (ioctl(_fd, SENSORIOCSQUEUEDEPTH, 5) != 0) { |
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hal.console->printf("Failed to setup RPM queue\n"); |
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close(_fd); |
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_fd = -1; |
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return; |
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} |
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} |
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/* |
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close the file descriptor |
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*/ |
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AP_RPM_PX4_PWM::~AP_RPM_PX4_PWM() |
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{ |
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if (_fd != -1) { |
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close(_fd); |
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_fd = -1; |
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} |
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} |
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void AP_RPM_PX4_PWM::update(void) |
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{ |
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if (_fd == -1) { |
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return; |
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} |
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struct pwm_input_s pwm; |
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uint16_t count = 0; |
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const float scaling = ap_rpm._scaling[state.instance]; |
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float sum = 0; |
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while (::read(_fd, &pwm, sizeof(pwm)) == sizeof(pwm)) { |
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// the px4 pwm_input driver reports the period in microseconds |
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if (pwm.period > RPM_MIN_PERIOD_US) { |
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sum += (1.0e6f * 60) / pwm.period; |
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count++; |
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} |
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} |
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if (count != 0) { |
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state.rate_rpm = scaling * sum / count; |
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state.last_reading_ms = hal.scheduler->millis(); |
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} |
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} |
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#endif // CONFIG_HAL_BOARD
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