#がいためIMU を Arduino で動かす SPRESENSE向けマルチIMU Add-onボード [CXD5602PWBIMU1J]

Gaitame.ino

// Spresense Multi-IMU[CXD5602PWBIMU1J] Sample for Arduino IDE
// 
// #がいためIMU
// by @GOROman

#include <stdio.h>
#include <sys/ioctl.h>
#include <time.h>
#include <inttypes.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <poll.h>
#include <errno.h>

// PWBIMU
#include <nuttx/sensors/cxd5602pwbimu.h>

extern "C" int board_cxd5602pwbimu_initialize(int);

// IMU設定
#define IMU_RATE (60)      // Hz
#define IMU_ADRANGE (4)    // G
#define IMU_GDRANGE (500)  // dps
#define IMU_FIFO (1)       // FIFO

static int fd;


void setup() {
  int ret = 0;

  // ↓これがないと動かん
  ret = board_cxd5602pwbimu_initialize(5);
  if (ret < 0)
  {
    printf("ERROR: Failed to initialize CXD5602PWBIMU.\n");
    return;
  }
  fd = open("/dev/imu0", O_RDONLY);
  if (fd < 0) {
    printf("ERROR: Could not open /dev/imu0\n");
    return;
  }

  ret = ioctl(fd, SNIOC_SSAMPRATE, IMU_RATE);
  if (ret) {
    printf("ERROR: Set sampling rate failed. %d\n", errno);
    return;
  }

  // レンジ設定
  cxd5602pwbimu_range_t range;
  range.accel = IMU_ADRANGE;
  range.gyro = IMU_GDRANGE;

  ret = ioctl(fd, SNIOC_SDRANGE, (unsigned long)(uintptr_t)&range);
  if (ret) {
    printf("ERROR: Set dynamic range failed. %d\n", errno);
    return;
  }
  // FIFO指定
  ret = ioctl(fd, SNIOC_SFIFOTHRESH, IMU_FIFO);
  if (ret) {
    printf("ERROR: Set FIFO failed. %d\n", errno);
    return;
  }
  ret = ioctl(fd, SNIOC_ENABLE, 1);
  if (ret) {
    printf("ERROR: Enable failed. %d\n", errno);
    return;
  }

  //delay(500);
  // ToDo 空読みしてバッファのゴミを捨てる
    
  printf("#timestamp,temp,ax,ay,az,gx,gy,gz\n");
}

void loop() {

  struct pollfd fds[1];
  fds[0].fd = fd;
  fds[0].events = POLLIN;

  // ポーリング
  int ret = poll(fds, 1, 1000);
  if (ret > 0) {
    // データ取得
    cxd5602pwbimu_data_t data;
    ret = read(fd, &data, sizeof(data));
    if (ret == sizeof(data)) {
      float timestamp = data.timestamp / 19200000.0f;
      printf("%4.2F,%4.2F,%F,%F,%F,%F,%F,%F\n", timestamp, data.temp, data.ax, data.ay, data.az, data.gx, data.gy, data.gz);
    }
  }
}

参考にさせていただいたもの
https://qiita.com/SaChiKaKK/items/50c550782b13fe43061e

https://github.com/SPRESENSE/nuttx/blob/487f65deff9f01b5878ad2e30e0783a64c305492/boards/arm/cxd56xx/spresense/src/cxd56_bringup.c#L270

これをexternしてユーザーが呼ぶ必要があるのは、まずいのではｗ

extern "C" int board_cxd5602pwbimu_initialize(int);