rpm_sensor.c

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/*
 * Copyright (C) Freek van Tienen <freek.v.tienen@gmail.com>
 *
 * This file is part of paparazzi
 *
 * paparazzi is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * paparazzi is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with paparazzi; see the file COPYING.  If not, see
 * <http://www.gnu.org/licenses/>.
 */
#include "modules/sensors/rpm_sensor.h"
#include "mcu_periph/pwm_input.h"
#include "subsystems/electrical.h"
#include "subsystems/abi.h"
#include "filters/low_pass_filter.h"

static struct FirstOrderLowPass rpm_lp;
uint16_t rpm;

#ifndef RPM_FILTER_TAU
#define RPM_FILTER_TAU RPM_SENSOR_PERIODIC_PERIOD
#endif


#if PERIODIC_TELEMETRY
#include "subsystems/datalink/telemetry.h"

static void rpm_sensor_send_motor(struct transport_tx *trans, struct link_device *dev)
{
  pprz_msg_send_MOTOR(trans, dev, AC_ID, &rpm, &electrical.current);
}
#endif

/* Initialize the RPM measurement by configuring the telemetry */
void rpm_sensor_init(void)
{
  rpm = 0;
  init_first_order_low_pass(&rpm_lp, RPM_FILTER_TAU, RPM_SENSOR_PERIODIC_PERIOD, 0);

#if PERIODIC_TELEMETRY
  register_periodic_telemetry(DefaultPeriodic, PPRZ_MSG_ID_MOTOR, rpm_sensor_send_motor);
#endif
}

/* RPM periodic */
void rpm_sensor_periodic(void)
{
  rpm = update_first_order_low_pass(&rpm_lp, rpm_sensor_get_rpm());
  AbiSendMsgRPM(RPM_SENSOR_ID, &rpm, 1);
}

/* Get the RPM sensor */
uint16_t rpm_sensor_get_rpm(void)
{
  uint16_t rpm_meas = 0;
  uint32_t period_us = get_pwm_input_period_in_usec(RPM_PWM_CHANNEL) * RPM_PULSE_PER_RND;
  if (period_us > 0) {
    rpm_meas = ((uint32_t)1000000 * 60) / period_us;
  }

  return rpm_meas;
}