navdata.c

Go to the documentation of this file.

/*
 * Copyright (C) 2016 The Paparazzi Team
 *
 * 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/>.
 */

/* Thanks to TU Delft by assigning students Dino Hensen, Vincent van Hoek for
 * their inital work and later improvements made in 2015 by Freek van Tienen
*/

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <termios.h>   /* for baud rates and options */
#include <unistd.h>
#include <string.h>
#include <math.h>
#include <errno.h>
#include <assert.h>
#include <pthread.h>

#include "std.h"
#include "navdata.h"
#include "subsystems/ins.h"
#include "subsystems/ahrs.h"
#include "subsystems/abi.h"
#include "mcu_periph/gpio.h"

/* Internal used functions */
static void *navdata_read(void *data __attribute__((unused)));
static void navdata_cmd_send(uint8_t cmd);
static bool navdata_baro_calib(void);
static void mag_freeze_check(void);
static void baro_update_logic(void);

/* Main navdata structure */
struct navdata_t navdata;

static uint8_t navdata_buffer[NAVDATA_PACKET_SIZE];
static bool navdata_available = false;

/* syncronization variables */
static pthread_mutex_t navdata_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t  navdata_cond  = PTHREAD_COND_INITIALIZER;

#ifndef NAVDATA_FILTER_ID
#define NAVDATA_FILTER_ID 2
#endif

#ifndef SONAR_OFFSET
#define SONAR_OFFSET 880
#endif

#ifndef SONAR_SCALE
#define SONAR_SCALE 0.00047
#endif

ssize_t full_write(int fd, const uint8_t *buf, size_t count)
{
  size_t written = 0;

  while (written < count) {
    ssize_t n = write(fd, buf + written, count - written);
    if (n < 0) {
      if (errno == EAGAIN || errno == EWOULDBLOCK) {
        continue;
      }
      return n;
    }
    written += n;
  }
  return written;
}

ssize_t full_read(int fd, uint8_t *buf, size_t count)
{
  /* Apologies for illiteracy, but we can't overload |read|.*/
  size_t readed = 0;

  while (readed < count) {
    ssize_t n = read(fd, buf + readed, count - readed);
    if (n < 0) {
      if (errno == EAGAIN || errno == EWOULDBLOCK) {
        continue;
      }
      return n;
    }
    readed += n;
  }
  return readed;
}

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

static void send_navdata(struct transport_tx *trans, struct link_device *dev)
{
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Waddress-of-packed-member"
  pprz_msg_send_ARDRONE_NAVDATA(trans, dev, AC_ID,
                                &navdata.measure.taille,
                                &navdata.measure.nu_trame,
                                &navdata.measure.ax,
                                &navdata.measure.ay,
                                &navdata.measure.az,
                                &navdata.measure.vx,
                                &navdata.measure.vy,
                                &navdata.measure.vz,
                                &navdata.measure.temperature_acc,
                                &navdata.measure.temperature_gyro,
                                &navdata.measure.ultrasound,
                                &navdata.measure.us_debut_echo,
                                &navdata.measure.us_fin_echo,
                                &navdata.measure.us_association_echo,
                                &navdata.measure.us_distance_echo,
                                &navdata.measure.us_curve_time,
                                &navdata.measure.us_curve_value,
                                &navdata.measure.us_curve_ref,
                                &navdata.measure.nb_echo,
                                &navdata.measure.sum_echo,
                                &navdata.measure.gradient,
                                &navdata.measure.flag_echo_ini,
                                &navdata.measure.pressure,
                                &navdata.measure.temperature_pressure,
                                &navdata.measure.mx,
                                &navdata.measure.my,
                                &navdata.measure.mz,
                                &navdata.measure.chksum,
                                &navdata.checksum_errors);
#pragma GCC diagnostic pop
}
#endif

bool navdata_init()
{
  assert(sizeof(struct navdata_measure_t) == NAVDATA_PACKET_SIZE);

  /* Check if the FD isn't already initialized */
  if (navdata.fd <= 0) {
    navdata.fd = open("/dev/ttyO1", O_RDWR | O_NOCTTY); /* O_NONBLOCK doesn't work */

    if (navdata.fd < 0) {
      printf("[navdata] Unable to open navdata board connection(/dev/ttyO1)\n");
      return false;
    }

    /* Update the settings of the UART connection */
    fcntl(navdata.fd, F_SETFL, 0); /* read calls are non blocking */
    /* set port options */
    struct termios options;
    /* Get the current options for the port */
    tcgetattr(navdata.fd, &options);
    /* Set the baud rates to 460800 */
    cfsetispeed(&options, B460800);
    cfsetospeed(&options, B460800);

    options.c_cflag |= (CLOCAL | CREAD); /* Enable the receiver and set local mode */
    options.c_iflag = 0; /* clear input options */
    options.c_lflag = 0; /* clear local options */
    options.c_oflag &= ~OPOST; //clear output options (raw output)

    //Set the new options for the port
    tcsetattr(navdata.fd, TCSANOW, &options);
  }

  // Reset available flags
  navdata_available = false;
  navdata.baro_calibrated = false;
  navdata.baro_available = false;
  navdata.imu_lost = false;

  // Set all statistics to 0
  navdata.checksum_errors = 0;
  navdata.lost_imu_frames = 0;
  navdata.totalBytesRead = 0;
  navdata.packetsRead = 0;
  navdata.last_packet_number = 0;

  /* Stop acquisition */
  navdata_cmd_send(NAVDATA_CMD_STOP);

  /* Read the baro calibration(blocking) */
  if (!navdata_baro_calib()) {
    printf("[navdata] Could not acquire baro calibration!\n");
    return false;
  }
  navdata.baro_calibrated = true;

  /* Start acquisition */
  navdata_cmd_send(NAVDATA_CMD_START);

  /* Set navboard gpio control */
  gpio_setup_output(ARDRONE_GPIO_PORT, ARDRONE_GPIO_PIN_NAVDATA);
  gpio_set(ARDRONE_GPIO_PORT, ARDRONE_GPIO_PIN_NAVDATA);

  /* Start navdata reading thread */
  pthread_t navdata_thread;
  if (pthread_create(&navdata_thread, NULL, navdata_read, NULL) != 0) {
    printf("[navdata] Could not create navdata reading thread!\n");
    return false;
  }
  pthread_setname_np(navdata_thread, "pprz_navdata_thread");

#if PERIODIC_TELEMETRY
  register_periodic_telemetry(DefaultPeriodic, PPRZ_MSG_ID_ARDRONE_NAVDATA, send_navdata);
#endif

  /* Set to initialized */
  navdata.is_initialized = true;
  return true;
}


static void *navdata_read(void *data __attribute__((unused)))
{
  /* Buffer insert index for reading/writing */
  static uint8_t buffer_idx = 0;

  while (TRUE) {

    /* Wait until we are notified to read next data,
       i.e. buffer has been copied in navdata_update */
    pthread_mutex_lock(&navdata_mutex);
    while (navdata_available) {
      pthread_cond_wait(&navdata_cond, &navdata_mutex);
    }
    pthread_mutex_unlock(&navdata_mutex);

    /* Read new bytes */
    int newbytes = read(navdata.fd, navdata_buffer + buffer_idx, NAVDATA_PACKET_SIZE - buffer_idx);

    /* When there was no signal interrupt */
    if (newbytes > 0) {
      buffer_idx += newbytes;
      navdata.totalBytesRead += newbytes;
    }

    /* If we got a full packet */
    if (buffer_idx >= NAVDATA_PACKET_SIZE) {
      /* check if the start byte is correct */
      if (navdata_buffer[0] != NAVDATA_START_BYTE) {
        uint8_t *pint = memchr(navdata_buffer, NAVDATA_START_BYTE, buffer_idx);

        /* Check if we found the start byte in the read data */
        if (pint != NULL) {
          memmove(navdata_buffer, pint, NAVDATA_PACKET_SIZE - (pint - navdata_buffer));
          buffer_idx = pint - navdata_buffer;
          fprintf(stderr, "[navdata] sync error, startbyte not found, resetting...\n");
        } else {
          buffer_idx = 0;
        }
        continue;
      }

      /* full packet read with startbyte at the beginning, reset insert index */
      buffer_idx = 0;

      /* Calculate the checksum */
      uint16_t checksum = 0;
      for (int i = 2; i < NAVDATA_PACKET_SIZE - 2; i += 2) {
        checksum += navdata_buffer[i] + (navdata_buffer[i + 1] << 8);
      }

      struct navdata_measure_t *new_measurement = (struct navdata_measure_t *)navdata_buffer;

      /* Check if the checksum is OK */
      if (new_measurement->chksum != checksum) {
        fprintf(stderr, "[navdata] Checksum error [calculated: %d] [packet: %d] [diff: %d]\n",
                checksum, new_measurement->chksum, checksum - new_measurement->chksum);
        navdata.checksum_errors++;
        continue;
      }

      /* Set flag that we have new valid navdata */
      pthread_mutex_lock(&navdata_mutex);
      navdata_available = true;
      pthread_mutex_unlock(&navdata_mutex);
    }
  }

  return NULL;
}

#include "subsystems/imu.h"
static void navdata_publish_imu(void)
{
  RATES_ASSIGN(imu.gyro_unscaled, navdata.measure.vx, -navdata.measure.vy, -navdata.measure.vz);
  VECT3_ASSIGN(imu.accel_unscaled, navdata.measure.ax, 4096 - navdata.measure.ay, 4096 - navdata.measure.az);
  VECT3_ASSIGN(imu.mag_unscaled, -navdata.measure.mx, -navdata.measure.my, -navdata.measure.mz);
  imu_scale_gyro(&imu);
  imu_scale_accel(&imu);
  imu_scale_mag(&imu);
  uint32_t now_ts = get_sys_time_usec();
  AbiSendMsgIMU_GYRO_INT32(IMU_BOARD_ID, now_ts, &imu.gyro);
  AbiSendMsgIMU_ACCEL_INT32(IMU_BOARD_ID, now_ts, &imu.accel);
  AbiSendMsgIMU_MAG_INT32(IMU_BOARD_ID, now_ts, &imu.mag);
}

void navdata_update()
{
  /* Check if initialized */
  if (!navdata.is_initialized) {
    navdata_init();
    mag_freeze_check();
    return;
  }

  pthread_mutex_lock(&navdata_mutex);
  /* If we got a new navdata packet */
  if (navdata_available) {

    /* Copy the navdata packet */
    memcpy(&navdata.measure, navdata_buffer, NAVDATA_PACKET_SIZE);

    /* reset the flag */
    navdata_available = false;
    /* signal that we copied the buffer and new packet can be read */
    pthread_cond_signal(&navdata_cond);
    pthread_mutex_unlock(&navdata_mutex);

    /* Check if we missed a packet (our counter and the one from the navdata) */
    navdata.last_packet_number++;
    if (navdata.last_packet_number != navdata.measure.nu_trame) {
      fprintf(stderr, "[navdata] Lost frame: %d should have been %d\n",
              navdata.measure.nu_trame, navdata.last_packet_number);
      navdata.lost_imu_frames++;
    }
    navdata.last_packet_number = navdata.measure.nu_trame;

    /* Invert byte order so that TELEMETRY works better */
    uint8_t tmp;
    uint8_t *p = (uint8_t *) & (navdata.measure.pressure);
    tmp = p[0];
    p[0] = p[1];
    p[1] = tmp;
    p = (uint8_t *) & (navdata.measure.temperature_pressure);
    tmp = p[0];
    p[0] = p[1];
    p[1] = tmp;

    baro_update_logic();
    mag_freeze_check();

#ifdef USE_SONAR
    /* Check if there is a new sonar measurement and update the sonar */
    if (navdata.measure.ultrasound >> 15) {
      uint32_t now_ts = get_sys_time_usec();
      float sonar_meas = (float)((navdata.measure.ultrasound & 0x7FFF) - SONAR_OFFSET) * SONAR_SCALE;
      AbiSendMsgAGL(AGL_SONAR_ARDRONE2_ID, now_ts, sonar_meas);
    }
#endif

    navdata_publish_imu();

    navdata.packetsRead++;
  } else {
    /* no new packet available, still unlock mutex again */
    pthread_mutex_unlock(&navdata_mutex);
  }
}

static void navdata_cmd_send(uint8_t cmd)
{
  full_write(navdata.fd, &cmd, 1);
}


static bool navdata_baro_calib(void)
{
  /* Start baro calibration acquisition */
  navdata_cmd_send(NAVDATA_CMD_BARO_CALIB);

  /* Receive the calibration (blocking) */
  uint8_t calibBuffer[22];
  if (full_read(navdata.fd, calibBuffer, sizeof calibBuffer) < 0) {
    printf("[navdata] Could not read calibration data.");
    return false;
  }

  /* Convert the read bytes */
  navdata.bmp180_calib.ac1 = calibBuffer[0]  << 8 | calibBuffer[1];
  navdata.bmp180_calib.ac2 = calibBuffer[2]  << 8 | calibBuffer[3];
  navdata.bmp180_calib.ac3 = calibBuffer[4]  << 8 | calibBuffer[5];
  navdata.bmp180_calib.ac4 = calibBuffer[6]  << 8 | calibBuffer[7];
  navdata.bmp180_calib.ac5 = calibBuffer[8]  << 8 | calibBuffer[9];
  navdata.bmp180_calib.ac6 = calibBuffer[10] << 8 | calibBuffer[11];
  navdata.bmp180_calib.b1  = calibBuffer[12] << 8 | calibBuffer[13];
  navdata.bmp180_calib.b2  = calibBuffer[14] << 8 | calibBuffer[15];
  navdata.bmp180_calib.mb  = calibBuffer[16] << 8 | calibBuffer[17];
  navdata.bmp180_calib.mc  = calibBuffer[18] << 8 | calibBuffer[19];
  navdata.bmp180_calib.md  = calibBuffer[20] << 8 | calibBuffer[21];

  return true;
}

static void mag_freeze_check(void)
{
  /* Thanks to Daren.G.Lee for initial fix on 20140530 */
  static int16_t LastMagValue = 0;
  static int MagFreezeCounter = 0;

  if (LastMagValue == navdata.measure.mx) {
    MagFreezeCounter++;

    /* Has to have at least 30 times the exact same value to consider it a frozen magnetometer value */
    if (MagFreezeCounter > 30) {
      fprintf(stderr, "mag freeze detected, resetting!\n");

      /* set imu_lost flag */
      navdata.imu_lost = true;
      navdata.lost_imu_frames++;

      /* Stop acquisition */
      navdata_cmd_send(NAVDATA_CMD_STOP);

      /* Reset the hardware of the navboard */
      gpio_clear(ARDRONE_GPIO_PORT, ARDRONE_GPIO_PIN_NAVDATA);
      usleep(20000);
      gpio_set(ARDRONE_GPIO_PORT, ARDRONE_GPIO_PIN_NAVDATA);

      /* Wait for 40ms for it to boot */
      usleep(40000);

      /* Start the navdata again and reset the counter */
      navdata_cmd_send(NAVDATA_CMD_START);
      MagFreezeCounter = 0; /* reset counter back to zero */
    }
  } else {
    navdata.imu_lost = false;
    /* Reset counter if value _does_ change */
    MagFreezeCounter = 0;
  }
  /* set last value */
  LastMagValue = navdata.measure.mx;
}

static void baro_update_logic(void)
{
  static int32_t lastpressval = 0;
  static uint16_t lasttempval = 0;
  static int32_t lastpressval_nospike = 0;
  static uint16_t lasttempval_nospike = 0;
  static uint8_t temp_or_press_was_updated_last =
    0; /* 0 = press, so we now wait for temp, 1 = temp so we now wait for press */

  static int sync_errors = 0;
  static int spike_detected = 0;

  if (temp_or_press_was_updated_last == 0) { /* Last update was press so we are now waiting for temp */
    /* temp was updated */
    temp_or_press_was_updated_last = true;

    /* This means that press must remain constant */
    if (lastpressval != 0) {
      /* If pressure was updated: this is a sync error */
      if (lastpressval != navdata.measure.pressure) {
        /* wait for temp again */
        temp_or_press_was_updated_last = false;
        sync_errors++;
        //printf("Baro-Logic-Error (expected updated temp, got press)\n");
      }
    }
  } else {
    /* press was updated */
    temp_or_press_was_updated_last = false;

    /* This means that temp must remain constant */
    if (lasttempval != 0) {
      /* If temp was updated: this is a sync error */
      if (lasttempval != navdata.measure.temperature_pressure) {
        /* wait for press again */
        temp_or_press_was_updated_last = true;
        sync_errors++;
        //printf("Baro-Logic-Error (expected updated press, got temp)\n");

      } else {
        /* We now got valid pressure and temperature */
        navdata.baro_available = true;
      }
    }
  }

  /* Detected a pressure swap */
  if (lastpressval != 0 && lasttempval != 0
      && ABS(lastpressval - navdata.measure.pressure) > ABS(lasttempval - navdata.measure.pressure)) {
    navdata.baro_available = false;
  }

  /* Detected a temprature swap */
  if (lastpressval != 0 && lasttempval != 0
      && ABS(lasttempval - navdata.measure.temperature_pressure) > ABS(lastpressval - navdata.measure.temperature_pressure)) {
    navdata.baro_available = false;
  }

  lasttempval = navdata.measure.temperature_pressure;
  lastpressval = navdata.measure.pressure;

  /*
   * It turns out that a lot of navdata boards have a problem (probably interrupt related)
   * in which reading I2C data and writing uart output data is interrupted very long (50% of 200Hz).
   * Afterwards, the 200Hz loop tries to catch up lost time but reads the baro too fast swapping the
   * pressure and temperature values by exceeding the minimal conversion time of the bosh baro. The
   * normal Parrot firmware seems to be perfectly capable to fly with this, either with excessive use of
   * the sonar or with software filtering or spike detection. Paparazzi with its tightly coupled baro-altitude
   * had problems. Since this problems looks not uncommon a detector was made. A lot of evidence is grabbed
   * with a logic analyzer on the navboard I2C and serial output. The UART CRC is still perfect, the baro
   * temp-press-temp-press logic is still perfect, so not easy to detect. Temp and pressure are swapped,
   * and since both can have almost the same value, the size of the spike is not predictable. However at
   * every spike of at least 3 broken boards the press and temp are byte-wise exactly the same due to
   * reading them too quickly (trying to catch up for delay that happened earlier due to still non understood
   * reasons. As pressure is more likely to quickly change, a small (yet unlikely) spike on temperature together with
   * press==temp yields very good results as a detector, although theoretically not perfect.

  #samp press temp.
  50925 39284 34501
  50926 39287 34501
  50927 39287 34501
  50928 39283 34501     // *press good -> baro
  50929 39283 34501
  50930 39285 34501     // *press good -> baro
  50931 39285 34500
  50932 34500 34500     // press read too soon from chip (<4.5ms) -> ADC register still previous temp value
  50933 34500 36618     // press not updated, still wrong. Temp is weird: looks like the average of both
  50934 39284 36618     // new press read, but temp still outdated
  50935 39284 34501
  50936 39284 34501     // *press good -> baro
  50937 39284 34500
  50938 39281 34500
  50939 39281 34500
  50940 39280 34500
  50941 39280 34502
  50942 39280 34502
  50943 39280 34501

   */

  /* If press and temp are same and temp has jump: neglect the next frame */
  if (navdata.measure.temperature_pressure ==
      navdata.measure.pressure) { // && (abs((int32_t)navdata.temperature_pressure - (int32_t)lasttempval) > 40))
    /* dont use the next 3 packets */
    spike_detected = 3;
  }

  if (spike_detected > 0) {
    /* disable kalman filter use */
    navdata.baro_available = false;

    // override both to last good
    navdata.measure.pressure = lastpressval_nospike;
    navdata.measure.temperature_pressure = lasttempval_nospike;

    /* Countdown */
    spike_detected--;
  } else { // both are good
    lastpressval_nospike = navdata.measure.pressure;
    lasttempval_nospike = navdata.measure.temperature_pressure;
  }
}