invensense3.c

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/*
 * Copyright (C) 2022 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, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
 
#include "peripherals/invensense3.h"
#include "peripherals/invensense3_regs.h"
#include "math/pprz_isa.h"
#include "math/pprz_algebra_int.h"
#include "math/pprz_algebra_float.h"
#include "modules/imu/imu.h"
#include "modules/core/abi.h"
#include "mcu_periph/gpio_arch.h"
#include "std.h"
 
/* Local functions */
static void invensense3_parse_fifo_data(struct invensense3_t *inv, uint8_t *data, uint16_t samples);
static void invensense3_parse_reg_data(struct invensense3_t *inv, uint8_t *data);
static void invensense3_fix_config(struct invensense3_t *inv);
static bool invensense3_register_write(struct invensense3_t *inv, uint16_t bank_reg, uint8_t value);
static bool invensense3_register_read(struct invensense3_t *inv, uint16_t bank_reg, uint16_t size);
static bool invensense3_select_bank(struct invensense3_t *inv, uint8_t bank);
static bool invensense3_config(struct invensense3_t *inv);
static bool invensense3_reset_fifo(struct invensense3_t *inv);
static int samples_from_odr(int odr);
 
/* Default gyro scalings */
static const struct FloatRates invensense3_gyro_scale_f[8] = {
  {4.36332, 4.36332, 4.36332},        // 2000DPS
  {2.18166, 2.18166, 2.18166},        // 1000DPS
  {1.09083, 1.09083, 1.09083},        // 500DPS
  {0.545415, 0.545415, 0.545415},     // 250DPS: RATE_BFP_OF_REAL(radians(250)/(2**15))
  {0.272707, 0.272707, 0.272707},     // 125DPS   
  {0.136353, 0.136353, 0.136353},     // 62.5DPS
  {0.0681769, 0.0681769, 0.0681769},  // 31.25DPS
  {0.0340884, 0.0340884, 0.0340884},  // 15.625DPS
};
static const struct FloatRates invensense3_gyro_scale_f[8] = {…};
 
/* Default accel scalings */
static const struct FloatVect3 invensense3_accel_scale_f[5] = {
  {9.81, 9.81, 9.81},             // 32G
  {4.905, 4.905, 4.905},          // 16G
  {2.4525,  2.4525,  2.4525},     // 8G
  {1.22583, 1.22583, 1.22583},    // 4G
  {0.61312, 0.61312, 0.61312},    // 2G: ACCEL_BFP_OF_REAL(2G*9.81/(2**15))
};
static const struct FloatVect3 invensense3_accel_scale_f[5] = {…};
 
/* AAF settings (3dB Bandwidth [Hz], AAF_DELT, AAF_DELTSQR, AAF_BITSHIFT) */
static const uint16_t invensense3_aaf[][4] = {
  {42, 1, 1, 15},
  {84, 2, 4, 13},
  {126, 3, 9, 12},
  {170, 4, 16, 11},
  {213, 5, 25, 10},
  {258, 6, 36, 10},
  {303, 7, 49, 9},
  {348, 8, 64, 9},
  {394, 9, 81, 9},
  {441, 10, 100, 8},
  {488, 11, 122, 8},
  {536, 12, 144, 8},
  {585, 13, 170, 8},
  {634, 14, 196, 7},
  {684, 15, 224, 7},
  {734, 16, 256, 7},
  {785, 17, 288, 7},
  {837, 18, 324, 7},
  {890, 19, 360, 6},
  {943, 20, 400, 6},
  {997, 21, 440, 6},
  {1051, 22, 488, 6},
  {1107, 23, 528, 6},
  {1163, 24, 576, 6},
  {1220, 25, 624, 6},
  {1277, 26, 680, 6},
  {1336, 27, 736, 5},
  {1395, 28, 784, 5},
  {1454, 29, 848, 5},
  {1515, 30, 896, 5},
  {1577, 31, 960, 5},
  {1639, 32, 1024, 5},
  {1702, 33, 1088, 5},
  {1766, 34, 1152, 5},
  {1830, 35, 1232, 5},
  {1896, 36, 1296, 5},
  {1962, 37, 1376, 4},
  {2029, 38, 1440, 4},
  {2097, 39, 1536, 4},
  {2166, 40, 1600, 4},
  {2235, 41, 1696, 4},
  {2306, 42, 1760, 4},
  {2377, 43, 1856, 4},
  {2449, 44, 1952, 4},
  {2522, 45, 2016, 4},
  {2596, 46, 2112, 4},
  {2671, 47, 2208, 4},
  {2746, 48, 2304, 4},
  {2823, 49, 2400, 4},
  {2900, 50, 2496, 4},
  {2978, 51, 2592, 4},
  {3057, 52, 2720, 4},
  {3137, 53, 2816, 3},
  {3217, 54, 2944, 3},
  {3299, 55, 3008, 3},
  {3381, 56, 3136, 3},
  {3464, 57, 3264, 3},
  {3548, 58, 3392, 3},
  {3633, 59, 3456, 3},
  {3718, 60, 3584, 3},
  {3805, 61, 3712, 3},
  {3892, 62, 3840, 3},
  {3979, 63, 3968, 3}
};
static const uint16_t invensense3_aaf[][4] = {…};
 
static const uint16_t invensense3_aaf4x605[][4] = {
  {10, 1, 1, 15},
  {21, 2, 4, 13},
  {32, 3, 9, 12},
  {42, 4, 16, 11},
  {53, 5, 25, 10},
  {64, 6, 36, 10},
  {76, 7, 49, 9},
  {87, 8, 64, 9},
  {99, 9, 81, 9},
  {110, 10, 100, 8},
  {122, 11, 122, 8},
  {134, 12, 144, 8},
  {146, 13, 170, 8},
  {158, 14, 196, 7},
  {171, 15, 224, 7},
  {184, 16, 256, 7},
  {196, 17, 288, 7},
  {209, 18, 324, 7},
  {222, 19, 360, 6},
  {236, 20, 400, 6},
  {249, 21, 440, 6},
  {263, 22, 488, 6},
  {277, 23, 528, 6},
  {291, 24, 576, 6},
  {305, 25, 624, 6},
  {319, 26, 680, 6},
  {334, 27, 736, 5},
  {349, 28, 784, 5},
  {364, 29, 848, 5},
  {379, 30, 896, 5},
  {394, 31, 960, 5},
  {410, 32, 1024, 5},
  {425, 33, 1088, 5},
  {441, 34, 1152, 5},
  {458, 35, 1232, 5},
  {474, 36, 1296, 5},
  {490, 37, 1376, 4},
  {507, 38, 1440, 4},
  {524, 39, 1536, 4},
  {541, 40, 1600, 4},
  {559, 41, 1696, 4},
  {576, 42, 1760, 4},
  {594, 43, 1856, 4},
  {612, 44, 1952, 4},
  {631, 45, 2016, 4},
  {649, 46, 2112, 4},
  {668, 47, 2208, 4},
  {687, 48, 2304, 4},
  {706, 49, 2400, 4},
  {725, 50, 2496, 4},
  {745, 51, 2592, 4},
  {764, 52, 2720, 4},
  {784, 53, 2816, 3},
  {804, 54, 2944, 3},
  {825, 55, 3008, 3},
  {845, 56, 3136, 3},
  {866, 57, 3264, 3},
  {887, 58, 3392, 3},
  {908, 59, 3456, 3},
  {930, 60, 3584, 3},
  {951, 61, 3712, 3},
  {973, 62, 3840, 3},
  {995, 63, 3968, 3}
};
static const uint16_t invensense3_aaf4x605[][4] = {…};
 
static const uint8_t invensense3_fifo_sample_size[4] = {8,8,16,20};
 
void invensense3_init(struct invensense3_t *inv) {
  /* General setup */
  inv->status = INVENSENSE3_IDLE;
  inv->device = INVENSENSE3_UNKOWN;
  inv->register_bank = 0xFF;
  inv->config_idx = 0;
  
  /* SPI setup */
  if(inv->bus == INVENSENSE3_SPI) {
    inv->spi.trans.cpol = SPICpolIdleHigh;
    inv->spi.trans.cpha = SPICphaEdge2;
    inv->spi.trans.dss = SPIDss8bit;
    inv->spi.trans.bitorder = SPIMSBFirst;
    inv->spi.trans.cdiv = SPIDiv16;
 
    inv->spi.trans.select = SPISelectUnselect;
    inv->spi.trans.slave_idx = inv->spi.slave_idx;
    inv->spi.trans.output_length = 0;
    inv->spi.trans.input_length = 0;
    inv->spi.trans.before_cb = NULL;
    inv->spi.trans.after_cb = NULL;
    inv->spi.trans.input_buf = inv->spi.rx_buf;
    inv->spi.trans.output_buf = inv->spi.tx_buf;
    inv->spi.trans.status = SPITransDone;
 
    inv->rx_buffer = inv->spi.rx_buf;
    inv->tx_buffer = inv->spi.tx_buf;
    inv->rx_length = &inv->spi.trans.input_length;
  }
  /* I2C setup */
  else {
    inv->i2c.trans.slave_addr = inv->i2c.slave_addr;
    inv->i2c.trans.status = I2CTransDone;
 
    inv->rx_buffer = (uint8_t *)inv->i2c.trans.buf;
    inv->tx_buffer = (uint8_t *)inv->i2c.trans.buf;
    inv->rx_length = &inv->i2c.trans.len_r;
  }
 
  inv->sample_size = INVENSENSE3_SAMPLE_SIZE_PK3;
 
  inv->sample_numbers = samples_from_odr(Min((int)inv->gyro_odr, (int)inv->accel_odr));
}
void invensense3_init(struct invensense3_t *inv) {…}
 
void invensense3_periodic(struct invensense3_t *inv) {
  /* Idle */
  if((inv->bus == INVENSENSE3_SPI && inv->spi.trans.status == SPITransDone) || 
     (inv->bus == INVENSENSE3_I2C && inv->i2c.trans.status == I2CTransDone)) {
 
    /* Depending on the status choose what to do */
    switch(inv->status) {
      case INVENSENSE3_IDLE:
        /* Request WHO_AM_I */
        invensense3_register_read(inv, INV3REG_WHO_AM_I, 1);
        break;
 
      case INVENSENSE3_CONFIG:
        /* Start configuring */
        if(invensense3_config(inv)) {
          inv->status = INVENSENSE3_RUNNING;
        }
        break;
 
      case INVENSENSE3_RUNNING:
        /* Request a sensor reading */
        switch (inv->parser) {
          case INVENSENSE3_PARSER_REGISTERS:
            invensense3_register_read(inv, INV3REG_TEMP_DATA1, 14);
            break;
          case INVENSENSE3_PARSER_FIFO:
          {
            static const uint16_t max_bytes = sizeof(inv->spi.rx_buf) - 3;
            int read_bytes = (inv->sample_numbers + inv->timer) * invensense3_fifo_sample_size[inv->sample_size];
            read_bytes = Min(max_bytes, read_bytes);
            // round to the packet boundaries
            read_bytes -= read_bytes % invensense3_fifo_sample_size[inv->sample_size];
            invensense3_register_read(inv, INV3REG_FIFO_COUNTH, read_bytes + 2);
            inv->timer = 0; // reset leftover bytes
            break;
          }
          default: break;
        }
      
      default: break;
    }
  }
}
void invensense3_periodic(struct invensense3_t *inv) {…}
 
void invensense3_event(struct invensense3_t *inv) {
 
  /* Successful transfer */
  if((inv->bus == INVENSENSE3_SPI && inv->spi.trans.status == SPITransSuccess) || 
     (inv->bus == INVENSENSE3_I2C && inv->i2c.trans.status == I2CTransSuccess)) {
 
    /* Update the register bank */
    if(inv->tx_buffer[0] == INV3REG_BANK_SEL)
      inv->register_bank = inv->tx_buffer[1];
 
    /* Set the transaction as done and update register bank if needed */
    if(inv->bus == INVENSENSE3_SPI)
      inv->spi.trans.status = SPITransDone;
    else
      inv->i2c.trans.status = I2CTransDone;
    
    /* Look at the results */
    switch(inv->status) {
      case INVENSENSE3_IDLE:
        /* Check the response of the WHO_AM_I */
        inv->status = INVENSENSE3_CONFIG;
        if(inv->rx_buffer[1] == INV3_WHOAMI_ICM40605) {
          inv->device = INVENSENSE3_ICM40605;
        } else if(inv->rx_buffer[1] == INV3_WHOAMI_ICM40609) {
          inv->device = INVENSENSE3_ICM40609;
        } else if(inv->rx_buffer[1] == INV3_WHOAMI_ICM42605) {
          inv->device = INVENSENSE3_ICM42605;
        } else if(inv->rx_buffer[1] == INV3_WHOAMI_IIM42652) {
          inv->device = INVENSENSE3_IIM42652;
        } else if(inv->rx_buffer[1] == INV3_WHOAMI_ICM42688) {
          inv->device = INVENSENSE3_ICM42688;
        } else {
          inv->status = INVENSENSE3_IDLE;
        }
 
        /* Fix the configuration and set the scaling */
        if(inv->status == INVENSENSE3_CONFIG)
          invensense3_fix_config(inv);
        break;
 
      case INVENSENSE3_CONFIG:
        /* Apply the next configuration register */
        if(invensense3_config(inv)) {
          inv->status = INVENSENSE3_RUNNING;
        }
        break;
 
      case INVENSENSE3_RUNNING:
        /* Select the desired parser */
        switch (inv->parser) {
          case INVENSENSE3_PARSER_REGISTERS:
            invensense3_parse_reg_data(inv, &inv->rx_buffer[1]);
            break;
 
          case INVENSENSE3_PARSER_FIFO: {
            /* Parse the results */
            uint16_t n_samples = (uint16_t)inv->rx_buffer[1] | inv->rx_buffer[2] << 8;
            uint16_t fifo_bytes = n_samples * invensense3_fifo_sample_size[inv->sample_size];
            
            inv->timer = n_samples;   // samples left in FIFO
 
            // Not enough data in FIFO
            if(n_samples == 0) {
              return;
            }
 
            // We read an incorrect length (try again)
            if(fifo_bytes > 4096) {
              invensense3_register_read(inv, INV3REG_FIFO_COUNTH, 2);
              return;
            }
 
            // Parse the data
            if(*inv->rx_length > 3) {
              uint16_t nb_packets_read = (*inv->rx_length - 3) / invensense3_fifo_sample_size[inv->sample_size];
              invensense3_parse_fifo_data(inv, &inv->rx_buffer[3], Min(n_samples, nb_packets_read));
              inv->timer -= nb_packets_read;
            }
 
            break;
          }
          default: break;
        }
        break;
 
      default:
        inv->status = INVENSENSE3_IDLE;
        break;
    }
  }
  
  /* Failed transaction */
  if((inv->bus == INVENSENSE3_SPI && inv->spi.trans.status == SPITransFailed) || 
    (inv->bus == INVENSENSE3_I2C && inv->i2c.trans.status == I2CTransFailed)) {
 
    /* Set the transaction as done and update register bank if needed */
    if(inv->bus == INVENSENSE3_SPI) {
      inv->spi.trans.status = SPITransDone;
    }
    else {
      inv->i2c.trans.status = I2CTransDone;
    }
 
    /* Retry or ignore */
    switch(inv->status) {
      case INVENSENSE3_CONFIG:
        /* If was not a bus switch decrease the index */
        if(inv->config_idx > 0 && inv->tx_buffer[0] != INV3REG_BANK_SEL) {
          inv->config_idx--;
        }
        /* Try again */
        if(invensense3_config(inv)) {
          inv->status = INVENSENSE3_RUNNING;
        }
        break;
      case INVENSENSE3_IDLE:
      case INVENSENSE3_RUNNING: 
        /* Ignore while idle/running */
      default:
        break;
    }
  }
}
void invensense3_event(struct invensense3_t *inv) {…}
 
static void invensense3_parse_fifo_data(struct invensense3_t *inv, uint8_t *data, uint16_t samples) {
  static struct Int32Vect3 accel[INVENSENSE3_FIFO_BUFFER_LEN] = {0};
  static struct Int32Rates gyro[INVENSENSE3_FIFO_BUFFER_LEN] = {0};
 
  samples = Min(samples, INVENSENSE3_FIFO_BUFFER_LEN);
 
  uint8_t gyro_samplerate  = 17 - inv->gyro_odr;
  uint8_t accel_samplerate = 17 - inv->accel_odr;
 
  uint8_t faster_odr = gyro_samplerate;
  if (accel_samplerate > gyro_samplerate)
    faster_odr = accel_samplerate;
 
  // Go through the different samples
  uint8_t i = 0;
  uint8_t j = 0;
  int32_t temp = 0;
  uint16_t gyro_samplerate_count;
  uint16_t accel_samplerate_count;
  for(uint8_t sample = 0; sample < samples; sample++) { 
 
    if ((data[0] & 0xFC) != 0x68) {
        // no or bad data
    } else {
      
      gyro_samplerate_count = gyro_samplerate * (sample + 1);
      if(gyro_samplerate_count % faster_odr == 0) {
        gyro[i].p =  (int16_t)((uint16_t)data[7]  | data[8]  << 8 );
        gyro[i].q =  (int16_t)((uint16_t)data[9]  | data[10] << 8 );
        gyro[i].r =  (int16_t)((uint16_t)data[11] | data[12] << 8 );
        
        // Temperature sensor register data TEMP_DATA is updated with new data at max(Accelerometer ODR, Gyroscope ODR)
        if(gyro_samplerate == faster_odr)
          temp += (int8_t)data[13];
        
        i++;
      }
 
      accel_samplerate_count = accel_samplerate * (sample + 1);
      if(accel_samplerate_count % faster_odr == 0) {
        accel[j].x =  (int16_t)((uint16_t)data[1] | data[2] << 8 );
        accel[j].y =  (int16_t)((uint16_t)data[3] | data[4] << 8 );
        accel[j].z =  (int16_t)((uint16_t)data[5] | data[6] << 8 );
 
        if(accel_samplerate == faster_odr)
          temp += (int8_t)data[13];
 
        j++;
      }
    }
 
      data += invensense3_fifo_sample_size[inv->sample_size];
  }
 
  // ADC temp * temp sensitivity + temp zero
  float temp_f = ((float)temp / i) / 2.07 + 25.f; 
  if (accel_samplerate == faster_odr)
    temp_f = ((float)temp / j) / 2.07 + 25.f;
 
  // Send the scaled values over ABI
  uint32_t now_ts = get_sys_time_usec();
  AbiSendMsgIMU_GYRO_RAW(inv->abi_id, now_ts, gyro, i, inv->gyro_samplerate, temp_f);
  AbiSendMsgIMU_ACCEL_RAW(inv->abi_id, now_ts, accel, j, inv->accel_samplerate, temp_f);
  AbiSendMsgTEMPERATURE(inv->abi_id, temp_f);
}
static void invensense3_parse_fifo_data(struct invensense3_t *inv, uint8_t *data, uint16_t samples) {…}
 
static void invensense3_parse_reg_data(struct invensense3_t *inv, uint8_t *data) {
  static struct Int32Vect3 accel[1] = {0};
  static struct Int32Rates gyro[1] = {0};
  
  int32_t temp = (int16_t)((uint16_t)data[0]  | data[1] << 8);
  // ADC temp * temp sensitivity + temp zero
  float temp_f = (float)temp / 132.48 + 25.f;
 
  accel[0].x =  (int16_t)((uint16_t)data[2] | data[3] << 8 );
  accel[0].y =  (int16_t)((uint16_t)data[4] | data[5] << 8 );
  accel[0].z =  (int16_t)((uint16_t)data[6] | data[7] << 8 );
 
  gyro[0].p =  (int16_t)((uint16_t)data[8] | data[9]  << 8 );
  gyro[0].q =  (int16_t)((uint16_t)data[10]| data[11] << 8 );
  gyro[0].r =  (int16_t)((uint16_t)data[12]| data[13] << 8 );
 
  // Send the scaled values over ABI
  uint32_t now_ts = get_sys_time_usec();
  AbiSendMsgIMU_GYRO_RAW(inv->abi_id, now_ts, gyro, 1, inv->gyro_samplerate, temp_f);
  AbiSendMsgIMU_ACCEL_RAW(inv->abi_id, now_ts, accel, 1, inv->accel_samplerate, temp_f);
  AbiSendMsgTEMPERATURE(inv->abi_id, temp_f);
}
static void invensense3_parse_reg_data(struct invensense3_t *inv, uint8_t *data) {…}
 
static void invensense3_fix_config(struct invensense3_t *inv) {
  /* Fix wrong configuration settings (prevent user error) */
  if(inv->gyro_odr > INVENSENSE3_GYRO_ODR_12_5HZ && inv->gyro_odr != INVENSENSE3_GYRO_ODR_500HZ)
    inv->gyro_odr = INVENSENSE3_GYRO_ODR_12_5HZ;
  
  if(inv->device == INVENSENSE3_ICM40605 || inv->device == INVENSENSE3_ICM42605) {
    if(inv->gyro_odr > INVENSENSE3_GYRO_ODR_25HZ && inv->gyro_odr != INVENSENSE3_GYRO_ODR_500HZ)
      inv->gyro_odr = INVENSENSE3_GYRO_ODR_25HZ;
    else if(inv->gyro_odr < INVENSENSE3_GYRO_ODR_8KHZ)
      inv->gyro_odr = INVENSENSE3_GYRO_ODR_8KHZ;
    
    if(inv->device == INVENSENSE3_ICM40605 && inv->accel_odr > INVENSENSE3_ACCEL_ODR_25HZ && inv->accel_odr != INVENSENSE3_ACCEL_ODR_500HZ)
      inv->accel_odr = INVENSENSE3_ACCEL_ODR_25HZ;
    else if(inv->accel_odr < INVENSENSE3_ACCEL_ODR_8KHZ)
      inv->accel_odr = INVENSENSE3_ACCEL_ODR_8KHZ;
  }
 
  if(inv->device != INVENSENSE3_ICM40609 && inv->accel_range < INVENSENSE3_ACCEL_RANGE_16G)
    inv->accel_range = INVENSENSE3_ACCEL_RANGE_16G;
  else if(inv->device == INVENSENSE3_ICM40609 && inv->accel_range > INVENSENSE3_ACCEL_RANGE_4G)
    inv->accel_range = INVENSENSE3_ACCEL_RANGE_4G;
 
  /* Fix the AAF bandwidth setting */
  const uint16_t (*aaf_table)[4];
  uint16_t aaf_len;
  if(inv->device == INVENSENSE3_ICM40605 || inv->device == INVENSENSE3_ICM42605) {
    aaf_len = sizeof(invensense3_aaf4x605) / sizeof(invensense3_aaf4x605[0]);
    aaf_table = invensense3_aaf4x605;
  }
  else {
    aaf_len = sizeof(invensense3_aaf) / sizeof(invensense3_aaf[0]);
    aaf_table = invensense3_aaf;
  }
 
  uint16_t i = 0;
  for(i = 0; i < aaf_len; i++) {
    if(inv->gyro_aaf <= aaf_table[i][0]) {
      inv->gyro_aaf = aaf_table[i][0];
      RMAT_COPY(inv->gyro_aaf_regs, aaf_table[i]);
      break;
    }
  }
  if(i >= (aaf_len-1)) {
    inv->gyro_aaf = aaf_table[aaf_len-1][0];
    RMAT_COPY(inv->gyro_aaf_regs, aaf_table[aaf_len-1]);
  }
 
  for(i = 0; i < aaf_len; i++) {
    if(inv->accel_aaf <= aaf_table[i][0]) {
      inv->accel_aaf = aaf_table[i][0];
      RMAT_COPY(inv->accel_aaf_regs, aaf_table[i]);
      break;
    }
  }
  if(i >= (aaf_len-1)) {
    inv->accel_aaf = aaf_table[aaf_len-1][0];
    RMAT_COPY(inv->accel_aaf_regs, aaf_table[aaf_len-1]);
  }
 
  /* Calculate the samplerates in Hz */
  switch(inv->gyro_odr) {
    case INVENSENSE3_GYRO_ODR_32KHZ:
      inv->gyro_samplerate = 32000;
      break;
    case INVENSENSE3_GYRO_ODR_16KHZ:
      inv->gyro_samplerate  = 16000;
      break;
    case INVENSENSE3_GYRO_ODR_8KHZ:
      inv->gyro_samplerate  = 8000;
      break;
    case INVENSENSE3_GYRO_ODR_4KHZ:
      inv->gyro_samplerate  = 4000;
      break;
    case INVENSENSE3_GYRO_ODR_2KHZ:
      inv->gyro_samplerate  = 2000;
      break;
    case INVENSENSE3_GYRO_ODR_1KHZ:
      inv->gyro_samplerate  = 1000;
      break;
    case INVENSENSE3_GYRO_ODR_200HZ:
      inv->gyro_samplerate  = 200;
      break;
    case INVENSENSE3_GYRO_ODR_100HZ:
      inv->gyro_samplerate  = 100;
      break;
    case INVENSENSE3_GYRO_ODR_50HZ:
      inv->gyro_samplerate  = 50;
      break;
    case INVENSENSE3_GYRO_ODR_25HZ:
      inv->gyro_samplerate  = 25;
      break;
    case INVENSENSE3_GYRO_ODR_12_5HZ:
      inv->gyro_samplerate  = 12.5;
      break;
    case INVENSENSE3_GYRO_ODR_6_25HZ:
      inv->gyro_samplerate  = 6.25;
      break;
    case INVENSENSE3_GYRO_ODR_3_125HZ:
      inv->gyro_samplerate  = 3.125;
      break;
    case INVENSENSE3_GYRO_ODR_1_5625HZ:
      inv->gyro_samplerate  = 1.5625;
      break;
    case INVENSENSE3_GYRO_ODR_500HZ:
      inv->gyro_samplerate  = 500;
      break;
  }
  switch(inv->accel_odr) {
    case INVENSENSE3_ACCEL_ODR_32KHZ:
      inv->accel_samplerate = 32000;
      break;
    case INVENSENSE3_ACCEL_ODR_16KHZ:
      inv->accel_samplerate  = 16000;
      break;
    case INVENSENSE3_ACCEL_ODR_8KHZ:
      inv->accel_samplerate  = 8000;
      break;
    case INVENSENSE3_ACCEL_ODR_4KHZ:
      inv->accel_samplerate  = 4000;
      break;
    case INVENSENSE3_ACCEL_ODR_2KHZ:
      inv->accel_samplerate  = 2000;
      break;
    case INVENSENSE3_ACCEL_ODR_1KHZ:
      inv->accel_samplerate  = 1000;
      break;
    case INVENSENSE3_ACCEL_ODR_200HZ:
      inv->accel_samplerate  = 200;
      break;
    case INVENSENSE3_ACCEL_ODR_100HZ:
      inv->accel_samplerate  = 100;
      break;
    case INVENSENSE3_ACCEL_ODR_50HZ:
      inv->accel_samplerate  = 50;
      break;
    case INVENSENSE3_ACCEL_ODR_25HZ:
      inv->accel_samplerate  = 25;
      break;
    case INVENSENSE3_ACCEL_ODR_12_5HZ:
      inv->accel_samplerate  = 12.5;
      break;
    case INVENSENSE3_ACCEL_ODR_6_25HZ:
      inv->accel_samplerate  = 6.25;
      break;
    case INVENSENSE3_ACCEL_ODR_3_125HZ:
      inv->accel_samplerate  = 3.125;
      break;
    case INVENSENSE3_ACCEL_ODR_1_5625HZ:
      inv->accel_samplerate  = 1.5625;
      break;
    case INVENSENSE3_ACCEL_ODR_500HZ:
      inv->accel_samplerate  = 500;
      break;
  }
  
  /* Set the default values */
  imu_set_defaults_gyro(inv->abi_id, NULL, NULL, &invensense3_gyro_scale_f[inv->gyro_range]);
  imu_set_defaults_accel(inv->abi_id, NULL, NULL, &invensense3_accel_scale_f[inv->accel_range]);
}
static void invensense3_fix_config(struct invensense3_t *inv) {…}
 
static bool invensense3_register_write(struct invensense3_t *inv, uint16_t bank_reg, uint8_t value) {
  /* Split the register and bank */
  uint8_t bank = bank_reg >> 8;
  uint8_t reg = bank_reg & 0xFF;
 
  /* Switch the register bank if needed */
  if(invensense3_select_bank(inv, bank)) {
    return false;
  }
 
  inv->tx_buffer[0] = reg;
  inv->tx_buffer[1] = value;
  
  /* SPI transaction */
  if(inv->bus == INVENSENSE3_SPI) {
    inv->spi.trans.output_length = 2;
    inv->spi.trans.input_length = 0;
    spi_submit(inv->spi.p, &(inv->spi.trans));
  }
  /* I2C transaction */
  else {
    i2c_transmit(inv->i2c.p, &(inv->i2c.trans), inv->i2c.slave_addr, 2);
  }
 
  return true;
}
static bool invensense3_register_write(struct invensense3_t *inv, uint16_t bank_reg, uint8_t value) {…}
 
static bool invensense3_register_read(struct invensense3_t *inv, uint16_t bank_reg, uint16_t size) {
  /* Split the register and bank */
  uint8_t bank = bank_reg >> 8;
  uint8_t reg = bank_reg & 0xFF;
 
  /* Switch the register bank if needed */
  if(invensense3_select_bank(inv, bank)) {
    return false;
  }
 
  inv->tx_buffer[0] = reg | INV3_READ_FLAG;
  /* SPI transaction */
  if(inv->bus == INVENSENSE3_SPI) {
    inv->spi.trans.output_length = 2;
    inv->spi.trans.input_length = 1 + size;
    inv->tx_buffer[1] = 0;
    spi_submit(inv->spi.p, &(inv->spi.trans));
  }
  /* I2C transaction */
  else {
    i2c_transceive(inv->i2c.p, &(inv->i2c.trans), inv->i2c.slave_addr, 1, (1 + size));
  }
 
  return true;
}
static bool invensense3_register_read(struct invensense3_t *inv, uint16_t bank_reg, uint16_t size) {…}
 
static bool invensense3_select_bank(struct invensense3_t *inv, uint8_t bank) {
  /* If we already selected the correct bank continue */
  if(inv->register_bank == bank)
    return false;
 
  inv->tx_buffer[0] = INV3REG_BANK_SEL;
  inv->tx_buffer[1] = bank;
  /* SPI transaction */
  if(inv->bus == INVENSENSE3_SPI) {
    inv->spi.trans.output_length = 2;
    inv->spi.trans.input_length = 0;
    spi_submit(inv->spi.p, &(inv->spi.trans));
  }
  /* I2C transaction */
  else {
    i2c_transmit(inv->i2c.p, &(inv->i2c.trans), inv->i2c.slave_addr, 2);
  }
  
  return true;
}
static bool invensense3_select_bank(struct invensense3_t *inv, uint8_t bank) {…}
 
static bool invensense3_reset_fifo(struct invensense3_t *inv) {
  if(invensense3_register_write(inv, INV3REG_SIGNAL_PATH_RESET, BIT_SIGNAL_PATH_RESET_FIFO_FLUSH))
    return true;
  return false;
}
static bool invensense3_reset_fifo(struct invensense3_t *inv) {…}
 
static bool invensense3_config(struct invensense3_t *inv) {
  switch(inv->config_idx) {
    case 0:
      /* Reset the device */
      if(invensense3_register_write(inv, INV3REG_DEVICE_CONFIG, BIT_DEVICE_CONFIG_SOFT_RESET_CONFIG))
        inv->config_idx++;
      inv->timer = get_sys_time_usec();
      break;
 
    case 1: 
      /* Because reset takes time wait ~5ms */
      if((get_sys_time_usec() - inv->timer) < 5e3)
        break;
 
      /* Start the accel en gyro in low noise mode */
      if(invensense3_register_write(inv, INV3REG_PWR_MGMT0, (ACCEL_MODE_LN << ACCEL_MODE_SHIFT) | (GYRO_MODE_LN << GYRO_MODE_SHIFT)))
        inv->config_idx++;
      inv->timer = get_sys_time_usec();
      break;
 
    case 2: 
      /* Because starting takes time wait ~1ms */
      if((get_sys_time_usec() - inv->timer) < 1e3)
        break;
 
      /* Configure the gyro ODR/FS */
      if(invensense3_register_write(inv, INV3REG_GYRO_CONFIG0, (inv->gyro_range << GYRO_FS_SEL_SHIFT) | (inv->gyro_odr << GYRO_ODR_SHIFT)))
        inv->config_idx++;
      break;
 
    case 3: {
      /* Configure the accel ODR/FS */
      uint8_t accel_config = (inv->accel_odr << ACCEL_ODR_SHIFT);
      if(inv->device == INVENSENSE3_ICM40609)
        accel_config |= inv->accel_range << ACCEL_FS_SEL_SHIFT;
      else
        accel_config |= (inv->accel_range - 1) << ACCEL_FS_SEL_SHIFT;
 
      if(invensense3_register_write(inv, INV3REG_ACCEL_CONFIG0, accel_config))
        inv->config_idx++;
      break;
    }
 
    case 4:
      /* Configure gyro AAF enable */
      if(invensense3_register_write(inv, INV3REG_GYRO_CONFIG_STATIC2, 0x00))
        inv->config_idx++;
      break;
    case 5:
      /* Configure gyro AAF DELT */
      if(invensense3_register_write(inv, INV3REG_GYRO_CONFIG_STATIC3, inv->gyro_aaf_regs[1]))
        inv->config_idx++;
      break;
    case 6:
      /* Configure gyro AAF DELTSQR lower */
      if(invensense3_register_write(inv, INV3REG_GYRO_CONFIG_STATIC4, (inv->gyro_aaf_regs[2]&0xFF)))
        inv->config_idx++;
      break;
    case 7:
      /* Configure gyro AAF DELTSQR upper and bitshift */
      if(invensense3_register_write(inv, INV3REG_GYRO_CONFIG_STATIC5, (inv->gyro_aaf_regs[3] << GYRO_AAF_BITSHIFT_SHIFT) | ((inv->gyro_aaf_regs[2]>>8) & 0x0F)))
        inv->config_idx++;
      break;
    case 8:
      /* Configure accel AAF enable and DELT */
      if(invensense3_register_write(inv, INV3REG_ACCEL_CONFIG_STATIC2, (inv->accel_aaf_regs[1] << ACCEL_AAF_DELT_SHIFT)))
        inv->config_idx++;
      break;
    case 9:
      /* Configure accel AAF DELTSQR lower */
      if(invensense3_register_write(inv, INV3REG_ACCEL_CONFIG_STATIC3, (inv->accel_aaf_regs[2]&0xFF)))
        inv->config_idx++;
      break;
    case 10:
      /* Configure accel AAF DELTSQR upper and bitshift */
      if(invensense3_register_write(inv, INV3REG_ACCEL_CONFIG_STATIC4, (inv->accel_aaf_regs[3] << ACCEL_AAF_BITSHIFT_SHIFT) | ((inv->accel_aaf_regs[2]>>8) & 0x0F)))
        inv->config_idx++;
      break;
 
    case 11:
      /* FIFO count in records (little-endian data) */
      if(invensense3_register_write(inv, INV3REG_INTF_CONFIG0, FIFO_COUNT_REC))
        inv->config_idx++;
      break;
    case 12:
      /* Disable AFSR, which changes noise sensitivity with angular rate, causing stuck gyro's for 2ms resulting in DC gyro bias */
      if(invensense3_register_write(inv, INV3REG_INTF_CONFIG1, 0x51))
        inv->config_idx++;
      break;
    case 13:
      /* FIFO Stop-on-Full mode (enable the FIFO) */
      if(invensense3_register_write(inv, INV3REG_FIFO_CONFIG , FIFO_CONFIG_MODE_STOP_ON_FULL << FIFO_CONFIG_MODE_SHIFT))
        inv->config_idx++;
      break;
    case 14:
      /* FIFO content: enable accel, gyro, temperature */
      if(invensense3_register_write(inv, INV3REG_FIFO_CONFIG1 , BIT_FIFO_CONFIG1_ACCEL_EN | 
                    BIT_FIFO_CONFIG1_GYRO_EN | BIT_FIFO_CONFIG1_TEMP_EN))
        inv->config_idx++;
      break;
    case 15:
      /* Set FIFO watermark to 1 (so that INT is triggered for each packet) */
      if(invensense3_register_write(inv, INV3REG_FIFO_CONFIG2, 20))
        inv->config_idx++;
      break;
    case 16:
      /* Set FIFO watermark to 1 (so that INT is triggered for each packet) */
      if(invensense3_register_write(inv, INV3REG_FIFO_CONFIG3, 0x00))
        inv->config_idx++;
      break;
    case 17:
      /* Enable interrupt pin/status */
        switch(inv->parser) {
          case INVENSENSE3_PARSER_REGISTERS:
            if(invensense3_register_write(inv, INV3REG_INT_SOURCE0, BIT_UI_DRDY_INT_EN))
              inv->config_idx++;
            break;
          case INVENSENSE3_PARSER_FIFO:
            if(invensense3_register_write(inv, INV3REG_INT_SOURCE0, BIT_FIFO_FULL_INT_EN | BIT_FIFO_THS_INT_EN))
              inv->config_idx++;
            break;
          default:
            break;
          }
      break;
    case 18:
      /* Interrupt pins ASYNC_RESET configuration */
      // Datasheet: "User should change setting to 0 from default setting of 1, for proper INT1 and INT2 pin operation"
      if(invensense3_register_write(inv, INV3REG_INT_CONFIG1, BIT_INT_ASYNC_RESET))
        inv->config_idx++;
      break;
    case 19:
      /* FIFO flush */
      if(invensense3_reset_fifo(inv))
        inv->config_idx++;
      break;
 
    default:
      inv->timer = 0;
      return true;
  }
  return false;
}
static bool invensense3_config(struct invensense3_t *inv) {…}
 
static int samples_from_odr(int odr) {
   float freq = 0;
   if(odr < INVENSENSE3_GYRO_ODR_200HZ) {
    freq = 32000 / pow(2, odr-INVENSENSE3_GYRO_ODR_32KHZ);
   }
   else if(odr < INVENSENSE3_GYRO_ODR_500HZ) {
    freq = 200 / pow(2, odr-INVENSENSE3_GYRO_ODR_200HZ);
   }
   else if(odr == INVENSENSE3_GYRO_ODR_500HZ) {
    freq = 500;
   } else {
    // error
   }
  return ceilf(freq/PERIODIC_FREQUENCY);
}
static int samples_from_odr(int odr) {…}