src/main/drivers/accgyro/accgyro_spi_bmi270.c

   1 /*
   2  * This file is part of Cleanflight and Betaflight.
   3  *
   4  * Cleanflight and Betaflight are free software. You can redistribute
   5  * this software and/or modify this software under the terms of the
   6  * GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * Cleanflight and Betaflight are distributed in the hope that they
  11  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  12  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this software.
  17  *
  18  * If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <stdbool.h>
  22 #include <stdint.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include "platform.h"
  27
  28 #ifdef USE_ACCGYRO_BMI270
  29
  30 #include "drivers/accgyro/accgyro.h"
  31 #include "drivers/accgyro/accgyro_spi_bmi270.h"
  32 #include "drivers/bus_spi.h"
  33 #include "drivers/exti.h"
  34 #include "drivers/io.h"
  35 #include "drivers/io_impl.h"
  36 #include "drivers/nvic.h"
  37 #include "drivers/sensor.h"
  38 #include "drivers/system.h"
  39 #include "drivers/time.h"
  40
  41 // 10 MHz max SPI frequency
  42 #define BMI270_MAX_SPI_CLK_HZ 10000000
  43
  44 #define BMI270_FIFO_FRAME_SIZE 6
  45
  46 #define BMI270_CONFIG_SIZE 328
  47
  48 // Declaration for the device config (microcode) that must be uploaded to the sensor
  49 extern const uint8_t bmi270_maximum_fifo_config_file[BMI270_CONFIG_SIZE];
  50
  51 #define BMI270_CHIP_ID 0x24
  52
  53 // BMI270 registers (not the complete list)
  54 typedef enum {
  55     BMI270_REG_CHIP_ID = 0x00,
  56     BMI270_REG_ERR_REG = 0x02,
  57     BMI270_REG_STATUS = 0x03,
  58     BMI270_REG_ACC_DATA_X_LSB = 0x0C,
  59     BMI270_REG_GYR_DATA_X_LSB = 0x12,
  60     BMI270_REG_SENSORTIME_0 = 0x18,
  61     BMI270_REG_SENSORTIME_1 = 0x19,
  62     BMI270_REG_SENSORTIME_2 = 0x1A,
  63     BMI270_REG_EVENT = 0x1B,
  64     BMI270_REG_INT_STATUS_0 = 0x1C,
  65     BMI270_REG_INT_STATUS_1 = 0x1D,
  66     BMI270_REG_INTERNAL_STATUS = 0x21,
  67     BMI270_REG_TEMPERATURE_LSB = 0x22,
  68     BMI270_REG_TEMPERATURE_MSB = 0x23,
  69     BMI270_REG_FIFO_LENGTH_LSB = 0x24,
  70     BMI270_REG_FIFO_LENGTH_MSB = 0x25,
  71     BMI270_REG_FIFO_DATA = 0x26,
  72     BMI270_REG_ACC_CONF = 0x40,
  73     BMI270_REG_ACC_RANGE = 0x41,
  74     BMI270_REG_GYRO_CONF = 0x42,
  75     BMI270_REG_GYRO_RANGE = 0x43,
  76     BMI270_REG_AUX_CONF = 0x44,
  77     BMI270_REG_FIFO_DOWNS = 0x45,
  78     BMI270_REG_FIFO_WTM_0 = 0x46,
  79     BMI270_REG_FIFO_WTM_1 = 0x47,
  80     BMI270_REG_FIFO_CONFIG_0 = 0x48,
  81     BMI270_REG_FIFO_CONFIG_1 = 0x49,
  82     BMI270_REG_SATURATION = 0x4A,
  83     BMI270_REG_INT1_IO_CTRL = 0x53,
  84     BMI270_REG_INT2_IO_CTRL = 0x54,
  85     BMI270_REG_INT_LATCH = 0x55,
  86     BMI270_REG_INT1_MAP_FEAT = 0x56,
  87     BMI270_REG_INT2_MAP_FEAT = 0x57,
  88     BMI270_REG_INT_MAP_DATA = 0x58,
  89     BMI270_REG_INIT_CTRL = 0x59,
  90     BMI270_REG_INIT_DATA = 0x5E,
  91     BMI270_REG_ACC_SELF_TEST = 0x6D,
  92     BMI270_REG_GYR_SELF_TEST_AXES = 0x6E,
  93     BMI270_REG_PWR_CONF = 0x7C,
  94     BMI270_REG_PWR_CTRL = 0x7D,
  95     BMI270_REG_CMD = 0x7E,
  96 } bmi270Register_e;
  97
  98 // BMI270 register configuration values
  99 typedef enum {
 100     BMI270_VAL_CMD_SOFTRESET = 0xB6,
 101     BMI270_VAL_CMD_FIFOFLUSH = 0xB0,
 102     BMI270_VAL_PWR_CTRL = 0x0E,              // enable gyro, acc and temp sensors
 103     BMI270_VAL_PWR_CONF = 0x02,              // disable advanced power save, enable FIFO self-wake
 104     BMI270_VAL_ACC_CONF_ODR800 = 0x0B,       // set acc sample rate to 800hz
 105     BMI270_VAL_ACC_CONF_ODR1600 = 0x0C,      // set acc sample rate to 1600hz
 106     BMI270_VAL_ACC_CONF_BWP = 0x02,          // set acc filter in normal mode
 107     BMI270_VAL_ACC_CONF_HP = 0x01,           // set acc in high performance mode
 108     BMI270_VAL_ACC_RANGE_8G = 0x02,          // set acc to 8G full scale
 109     BMI270_VAL_ACC_RANGE_16G = 0x03,         // set acc to 16G full scale
 110     BMI270_VAL_GYRO_CONF_ODR3200 = 0x0D,     // set gyro sample rate to 3200hz
 111     BMI270_VAL_GYRO_CONF_BWP = 0x02,         // set gyro filter in normal mode
 112     BMI270_VAL_GYRO_CONF_NOISE_PERF = 0x01,  // set gyro in high performance noise mode
 113     BMI270_VAL_GYRO_CONF_FILTER_PERF = 0x01, // set gyro in high performance filter mode
 114
 115     BMI270_VAL_GYRO_RANGE_2000DPS = 0x08,    // set gyro to 2000dps full scale
 116                                              // for some reason you have to enable the ois_range bit (bit 3) for 2000dps as well
 117                                              // or else the gyro scale will be 250dps when in prefiltered FIFO mode (not documented in datasheet!)
 118
 119     BMI270_VAL_INT_MAP_DATA_DRDY_INT1 = 0x04,// enable the data ready interrupt pin 1
 120     BMI270_VAL_INT_MAP_FIFO_WM_INT1 = 0x02,  // enable the FIFO watermark interrupt pin 1
 121     BMI270_VAL_INT1_IO_CTRL_PINMODE = 0x0A,  // active high, push-pull, output enabled, input disabled
 122     BMI270_VAL_FIFO_CONFIG_0 = 0x00,         // don't stop when full, disable sensortime frame
 123     BMI270_VAL_FIFO_CONFIG_1 = 0x80,         // only gyro data in FIFO, use headerless mode
 124     BMI270_VAL_FIFO_DOWNS = 0x00,            // select unfiltered gyro data with no downsampling (6.4KHz samples)
 125     BMI270_VAL_FIFO_WTM_0 = 0x06,            // set the FIFO watermark level to 1 gyro sample (6 bytes)
 126     BMI270_VAL_FIFO_WTM_1 = 0x00,            // FIFO watermark MSB
 127 } bmi270ConfigValues_e;
 128
 129 // Need to see at least this many interrupts during initialisation to confirm EXTI connectivity
 130 #define GYRO_EXTI_DETECT_THRESHOLD 1000
 131
 132 // BMI270 register reads are 16bits with the first byte a "dummy" value 0
 133 // that must be ignored. The result is in the second byte.
 134 static uint8_t bmi270RegisterRead(const extDevice_t *dev, bmi270Register_e registerId)
 135 {
 136     uint8_t data[2] = { 0, 0 };
 137
 138     if (spiReadRegMskBufRB(dev, registerId, data, 2)) {
 139         return data[1];
 140     } else {
 141         return 0;
 142     }
 143 }
 144
 145 static void bmi270RegisterWrite(const extDevice_t *dev, bmi270Register_e registerId, uint8_t value, unsigned delayMs)
 146 {
 147     spiWriteReg(dev, registerId, value);
 148     if (delayMs) {
 149         delay(delayMs);
 150     }
 151 }
 152
 153 // Toggle the CS to switch the device into SPI mode.
 154 // Device switches initializes as I2C and switches to SPI on a low to high CS transition
 155 static void bmi270EnableSPI(const extDevice_t *dev)
 156 {
 157     IOLo(dev->busType_u.spi.csnPin);
 158     delay(1);
 159     IOHi(dev->busType_u.spi.csnPin);
 160     delay(10);
 161 }
 162
 163 uint8_t bmi270Detect(const extDevice_t *dev)
 164 {
 165     spiSetClkDivisor(dev, spiCalculateDivider(BMI270_MAX_SPI_CLK_HZ));
 166     bmi270EnableSPI(dev);
 167
 168     if (bmi270RegisterRead(dev, BMI270_REG_CHIP_ID) == BMI270_CHIP_ID) {
 169         return BMI_270_SPI;
 170     }
 171
 172     return MPU_NONE;
 173 }
 174
 175 static void bmi270UploadConfig(const extDevice_t *dev)
 176 {
 177     bmi270RegisterWrite(dev, BMI270_REG_PWR_CONF, 0, 1);
 178     bmi270RegisterWrite(dev, BMI270_REG_INIT_CTRL, 0, 1);
 179
 180     // Transfer the config file
 181     spiWriteRegBuf(dev, BMI270_REG_INIT_DATA, (uint8_t *)bmi270_maximum_fifo_config_file, sizeof(bmi270_maximum_fifo_config_file));
 182
 183     delay(10);
 184     bmi270RegisterWrite(dev, BMI270_REG_INIT_CTRL, 1, 1);
 185 }
 186
 187 static void bmi270Config(gyroDev_t *gyro)
 188 {
 189     extDevice_t *dev = &gyro->dev;
 190
 191     // If running in hardware_lpf experimental mode then switch to FIFO-based,
 192     // 6.4KHz sampling, unfiltered data vs. the default 3.2KHz with hardware filtering
 193 #ifdef USE_GYRO_DLPF_EXPERIMENTAL
 194     const bool fifoMode = (gyro->hardware_lpf == GYRO_HARDWARE_LPF_EXPERIMENTAL);
 195 #else
 196     const bool fifoMode = false;
 197 #endif
 198
 199     // Perform a soft reset to set all configuration to default
 200     // Delay 100ms before continuing configuration
 201     bmi270RegisterWrite(dev, BMI270_REG_CMD, BMI270_VAL_CMD_SOFTRESET, 100);
 202
 203     // Toggle the chip into SPI mode
 204     bmi270EnableSPI(dev);
 205
 206     bmi270UploadConfig(dev);
 207
 208     // Configure the FIFO
 209     if (fifoMode) {
 210         bmi270RegisterWrite(dev, BMI270_REG_FIFO_CONFIG_0, BMI270_VAL_FIFO_CONFIG_0, 1);
 211         bmi270RegisterWrite(dev, BMI270_REG_FIFO_CONFIG_1, BMI270_VAL_FIFO_CONFIG_1, 1);
 212         bmi270RegisterWrite(dev, BMI270_REG_FIFO_DOWNS, BMI270_VAL_FIFO_DOWNS, 1);
 213         bmi270RegisterWrite(dev, BMI270_REG_FIFO_WTM_0, BMI270_VAL_FIFO_WTM_0, 1);
 214         bmi270RegisterWrite(dev, BMI270_REG_FIFO_WTM_1, BMI270_VAL_FIFO_WTM_1, 1);
 215     }
 216
 217     // Configure the accelerometer
 218     bmi270RegisterWrite(dev, BMI270_REG_ACC_CONF, (BMI270_VAL_ACC_CONF_HP << 7) | (BMI270_VAL_ACC_CONF_BWP << 4) | BMI270_VAL_ACC_CONF_ODR800, 1);
 219
 220     // Configure the accelerometer full-scale range
 221     bmi270RegisterWrite(dev, BMI270_REG_ACC_RANGE, BMI270_VAL_ACC_RANGE_16G, 1);
 222
 223     // Configure the gyro
 224     bmi270RegisterWrite(dev, BMI270_REG_GYRO_CONF, (BMI270_VAL_GYRO_CONF_FILTER_PERF << 7) | (BMI270_VAL_GYRO_CONF_NOISE_PERF << 6) | (BMI270_VAL_GYRO_CONF_BWP << 4) | BMI270_VAL_GYRO_CONF_ODR3200, 1);
 225
 226     // Configure the gyro full-range scale
 227     bmi270RegisterWrite(dev, BMI270_REG_GYRO_RANGE, BMI270_VAL_GYRO_RANGE_2000DPS, 1);
 228
 229     // Configure the gyro data ready interrupt
 230     if (fifoMode) {
 231         // Interrupt driven by FIFO watermark level
 232         bmi270RegisterWrite(dev, BMI270_REG_INT_MAP_DATA, BMI270_VAL_INT_MAP_FIFO_WM_INT1, 1);
 233     } else {
 234         // Interrupt driven by data ready
 235         bmi270RegisterWrite(dev, BMI270_REG_INT_MAP_DATA, BMI270_VAL_INT_MAP_DATA_DRDY_INT1, 1);
 236     }
 237
 238     // Configure the behavior of the INT1 pin
 239     bmi270RegisterWrite(dev, BMI270_REG_INT1_IO_CTRL, BMI270_VAL_INT1_IO_CTRL_PINMODE, 1);
 240
 241     // Configure the device for  performance mode
 242     bmi270RegisterWrite(dev, BMI270_REG_PWR_CONF, BMI270_VAL_PWR_CONF, 1);
 243
 244     // Enable the gyro, accelerometer and temperature sensor - disable aux interface
 245     bmi270RegisterWrite(dev, BMI270_REG_PWR_CTRL, BMI270_VAL_PWR_CTRL, 1);
 246
 247     // Flush the FIFO
 248     if (fifoMode) {
 249         bmi270RegisterWrite(dev, BMI270_REG_CMD, BMI270_VAL_CMD_FIFOFLUSH, 1);
 250     }
 251 }
 252
 253 extiCallbackRec_t bmi270IntCallbackRec;
 254
 255 /*
 256  * Gyro interrupt service routine
 257  */
 258 #ifdef USE_GYRO_EXTI
 259 // Called in ISR context
 260 // Gyro read has just completed
 261 busStatus_e bmi270Intcallback(uint32_t arg)
 262 {
 263     gyroDev_t *gyro = (gyroDev_t *)arg;
 264     int32_t gyroDmaDuration = cmpTimeCycles(getCycleCounter(), gyro->gyroLastEXTI);
 265
 266     if (gyroDmaDuration > gyro->gyroDmaMaxDuration) {
 267         gyro->gyroDmaMaxDuration = gyroDmaDuration;
 268     }
 269
 270     gyro->dataReady = true;
 271
 272     return BUS_READY;
 273 }
 274
 275 void bmi270ExtiHandler(extiCallbackRec_t *cb)
 276 {
 277     gyroDev_t *gyro = container_of(cb, gyroDev_t, exti);
 278     // Ideally we'd use a time to capture such information, but unfortunately the port used for EXTI interrupt does
 279     // not have an associated timer
 280     uint32_t nowCycles = getCycleCounter();
 281     gyro->gyroSyncEXTI = gyro->gyroLastEXTI + gyro->gyroDmaMaxDuration;
 282     gyro->gyroLastEXTI = nowCycles;
 283
 284     if (gyro->gyroModeSPI == GYRO_EXTI_INT_DMA) {
 285         spiSequence(&gyro->dev, gyro->segments);
 286     }
 287
 288     gyro->detectedEXTI++;
 289
 290 }
 291
 292 static void bmi270IntExtiInit(gyroDev_t *gyro)
 293 {
 294     if (gyro->mpuIntExtiTag == IO_TAG_NONE) {
 295         return;
 296     }
 297
 298     IO_t mpuIntIO = IOGetByTag(gyro->mpuIntExtiTag);
 299
 300     IOInit(mpuIntIO, OWNER_GYRO_EXTI, 0);
 301     EXTIHandlerInit(&gyro->exti, bmi270ExtiHandler);
 302     EXTIConfig(mpuIntIO, &gyro->exti, NVIC_PRIO_MPU_INT_EXTI, IOCFG_IN_FLOATING, BETAFLIGHT_EXTI_TRIGGER_RISING);
 303     EXTIEnable(mpuIntIO, true);
 304 }
 305 #else
 306 void bmi270ExtiHandler(extiCallbackRec_t *cb)
 307 {
 308     gyroDev_t *gyro = container_of(cb, gyroDev_t, exti);
 309     gyro->dataReady = true;
 310 }
 311 #endif
 312
 313 static bool bmi270AccRead(accDev_t *acc)
 314 {
 315     switch (acc->gyro->gyroModeSPI) {
 316     case GYRO_EXTI_INT:
 317     case GYRO_EXTI_NO_INT:
 318     {
 319         acc->gyro->dev.txBuf[0] = BMI270_REG_ACC_DATA_X_LSB | 0x80;
 320
 321         busSegment_t segments[] = {
 322                 {.u.buffers = {NULL, NULL}, 8, true, NULL},
 323                 {.u.buffers = {NULL, NULL}, 0, true, NULL},
 324         };
 325         segments[0].u.buffers.txData = acc->gyro->dev.txBuf;
 326         segments[0].u.buffers.rxData = acc->gyro->dev.rxBuf;
 327
 328         spiSequence(&acc->gyro->dev, &segments[0]);
 329
 330         // Wait for completion
 331         spiWait(&acc->gyro->dev);
 332
 333         // Fall through
 334         FALLTHROUGH;
 335     }
 336
 337     case GYRO_EXTI_INT_DMA:
 338     {
 339         // If read was triggered in interrupt don't bother waiting. The worst that could happen is that we pick
 340         // up an old value.
 341
 342         // This data was read from the gyro, which is the same SPI device as the acc
 343         uint16_t *accData = (uint16_t *)acc->gyro->dev.rxBuf;
 344         acc->ADCRaw[X] = accData[1];
 345         acc->ADCRaw[Y] = accData[2];
 346         acc->ADCRaw[Z] = accData[3];
 347         break;
 348     }
 349
 350     case GYRO_EXTI_INIT:
 351     default:
 352         break;
 353     }
 354
 355     return true;
 356 }
 357
 358 static bool bmi270GyroReadRegister(gyroDev_t *gyro)
 359 {
 360     uint16_t *gyroData = (uint16_t *)gyro->dev.rxBuf;
 361     switch (gyro->gyroModeSPI) {
 362     case GYRO_EXTI_INIT:
 363     {
 364         // Initialise the tx buffer to all 0x00
 365         memset(gyro->dev.txBuf, 0x00, 14);
 366 #ifdef USE_GYRO_EXTI
 367         // Check that minimum number of interrupts have been detected
 368
 369         // We need some offset from the gyro interrupts to ensure sampling after the interrupt
 370         gyro->gyroDmaMaxDuration = 5;
 371         // Using DMA for gyro access upsets the scheduler on the F4
 372         if (gyro->detectedEXTI > GYRO_EXTI_DETECT_THRESHOLD) {
 373             if (spiUseDMA(&gyro->dev)) {
 374                 gyro->dev.callbackArg = (uint32_t)gyro;
 375                 gyro->dev.txBuf[0] = BMI270_REG_ACC_DATA_X_LSB | 0x80;
 376                 gyro->segments[0].len = 14;
 377                 gyro->segments[0].callback = bmi270Intcallback;
 378                 gyro->segments[0].u.buffers.txData = gyro->dev.txBuf;
 379                 gyro->segments[0].u.buffers.rxData = gyro->dev.rxBuf;
 380                 gyro->segments[0].negateCS = true;
 381                 gyro->gyroModeSPI = GYRO_EXTI_INT_DMA;
 382             } else {
 383                 // Interrupts are present, but no DMA
 384                 gyro->gyroModeSPI = GYRO_EXTI_INT;
 385             }
 386         } else
 387 #endif
 388         {
 389             gyro->gyroModeSPI = GYRO_EXTI_NO_INT;
 390         }
 391         break;
 392     }
 393
 394     case GYRO_EXTI_INT:
 395     case GYRO_EXTI_NO_INT:
 396     {
 397         gyro->dev.txBuf[0] = BMI270_REG_GYR_DATA_X_LSB | 0x80;
 398
 399         busSegment_t segments[] = {
 400                 {.u.buffers = {NULL, NULL}, 8, true, NULL},
 401                 {.u.buffers = {NULL, NULL}, 0, true, NULL},
 402         };
 403         segments[0].u.buffers.txData = gyro->dev.txBuf;
 404         segments[0].u.buffers.rxData = gyro->dev.rxBuf;
 405
 406         spiSequence(&gyro->dev, &segments[0]);
 407
 408         // Wait for completion
 409         spiWait(&gyro->dev);
 410
 411         gyro->gyroADCRaw[X] = gyroData[1];
 412         gyro->gyroADCRaw[Y] = gyroData[2];
 413         gyro->gyroADCRaw[Z] = gyroData[3];
 414
 415         break;
 416     }
 417
 418     case GYRO_EXTI_INT_DMA:
 419     {
 420         // If read was triggered in interrupt don't bother waiting. The worst that could happen is that we pick
 421         // up an old value.
 422         gyro->gyroADCRaw[X] = gyroData[4];
 423         gyro->gyroADCRaw[Y] = gyroData[5];
 424         gyro->gyroADCRaw[Z] = gyroData[6];
 425         break;
 426     }
 427
 428     default:
 429         break;
 430     }
 431
 432     return true;
 433 }
 434
 435 #ifdef USE_GYRO_DLPF_EXPERIMENTAL
 436 static bool bmi270GyroReadFifo(gyroDev_t *gyro)
 437 {
 438     enum {
 439         IDX_REG = 0,
 440         IDX_SKIP,
 441         IDX_FIFO_LENGTH_L,
 442         IDX_FIFO_LENGTH_H,
 443         IDX_GYRO_XOUT_L,
 444         IDX_GYRO_XOUT_H,
 445         IDX_GYRO_YOUT_L,
 446         IDX_GYRO_YOUT_H,
 447         IDX_GYRO_ZOUT_L,
 448         IDX_GYRO_ZOUT_H,
 449         BUFFER_SIZE,
 450     };
 451
 452     bool dataRead = false;
 453     STATIC_DMA_DATA_AUTO uint8_t bmi270_tx_buf[BUFFER_SIZE] = {BMI270_REG_FIFO_LENGTH_LSB | 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 454     STATIC_DMA_DATA_AUTO uint8_t bmi270_rx_buf[BUFFER_SIZE];
 455
 456     // Burst read the FIFO length followed by the next 6 bytes containing the gyro axis data for
 457     // the first sample in the queue. It's possible for the FIFO to be empty so we need to check the
 458     // length before using the sample.
 459     spiReadWriteBuf(&gyro->dev, (uint8_t *)bmi270_tx_buf, bmi270_rx_buf, BUFFER_SIZE);   // receive response
 460
 461     int fifoLength = (uint16_t)((bmi270_rx_buf[IDX_FIFO_LENGTH_H] << 8) | bmi270_rx_buf[IDX_FIFO_LENGTH_L]);
 462
 463     if (fifoLength >= BMI270_FIFO_FRAME_SIZE) {
 464
 465         const int16_t gyroX = (int16_t)((bmi270_rx_buf[IDX_GYRO_XOUT_H] << 8) | bmi270_rx_buf[IDX_GYRO_XOUT_L]);
 466         const int16_t gyroY = (int16_t)((bmi270_rx_buf[IDX_GYRO_YOUT_H] << 8) | bmi270_rx_buf[IDX_GYRO_YOUT_L]);
 467         const int16_t gyroZ = (int16_t)((bmi270_rx_buf[IDX_GYRO_ZOUT_H] << 8) | bmi270_rx_buf[IDX_GYRO_ZOUT_L]);
 468
 469         // If the FIFO data is invalid then the returned values will be 0x8000 (-32768) (pg. 43 of datasheet).
 470         // This shouldn't happen since we're only using the data if the FIFO length indicates
 471         // that data is available, but this safeguard is needed to prevent bad things in
 472         // case it does happen.
 473         if ((gyroX != INT16_MIN) || (gyroY != INT16_MIN) || (gyroZ != INT16_MIN)) {
 474             gyro->gyroADCRaw[X] = gyroX;
 475             gyro->gyroADCRaw[Y] = gyroY;
 476             gyro->gyroADCRaw[Z] = gyroZ;
 477             dataRead = true;
 478         }
 479         fifoLength -= BMI270_FIFO_FRAME_SIZE;
 480     }
 481
 482     // If there are additional samples in the FIFO then we don't use those for now and simply
 483     // flush the FIFO. Under normal circumstances we only expect one sample in the FIFO since
 484     // the gyro loop is running at the native sample rate of 6.4KHz.
 485     // However the way the FIFO works in the sensor is that if a frame is partially read then
 486     // it remains in the queue instead of bein removed. So if we ever got into a state where there
 487     // was a partial frame or other unexpected data in the FIFO is may never get cleared and we
 488     // would end up in a lock state of always re-reading the same partial or invalid sample.
 489     if (fifoLength > 0) {
 490         // Partial or additional frames left - flush the FIFO
 491         bmi270RegisterWrite(&gyro->dev, BMI270_REG_CMD, BMI270_VAL_CMD_FIFOFLUSH, 0);
 492     }
 493
 494     return dataRead;
 495 }
 496 #endif
 497
 498 static bool bmi270GyroRead(gyroDev_t *gyro)
 499 {
 500 #ifdef USE_GYRO_DLPF_EXPERIMENTAL
 501     if (gyro->hardware_lpf == GYRO_HARDWARE_LPF_EXPERIMENTAL) {
 502         // running in 6.4KHz FIFO mode
 503         return bmi270GyroReadFifo(gyro);
 504     } else
 505 #endif
 506     {
 507         // running in 3.2KHz register mode
 508         return bmi270GyroReadRegister(gyro);
 509     }
 510 }
 511
 512 static void bmi270SpiGyroInit(gyroDev_t *gyro)
 513 {
 514     bmi270Config(gyro);
 515
 516 #if defined(USE_GYRO_EXTI)
 517     bmi270IntExtiInit(gyro);
 518 #endif
 519 }
 520
 521 static void bmi270SpiAccInit(accDev_t *acc)
 522 {
 523     // sensor is configured during gyro init
 524     acc->acc_1G = 512 * 4;   // 16G sensor scale
 525 }
 526
 527 bool bmi270SpiAccDetect(accDev_t *acc)
 528 {
 529     if (acc->mpuDetectionResult.sensor != BMI_270_SPI) {
 530         return false;
 531     }
 532
 533     acc->initFn = bmi270SpiAccInit;
 534     acc->readFn = bmi270AccRead;
 535
 536     return true;
 537 }
 538
 539
 540 bool bmi270SpiGyroDetect(gyroDev_t *gyro)
 541 {
 542     if (gyro->mpuDetectionResult.sensor != BMI_270_SPI) {
 543         return false;
 544     }
 545
 546     gyro->initFn = bmi270SpiGyroInit;
 547     gyro->readFn = bmi270GyroRead;
 548     gyro->scale = GYRO_SCALE_2000DPS;
 549
 550     return true;
 551 }
 552
 553 // Used to query the status register to determine what event caused the EXTI to fire.
 554 // When in 3.2KHz mode the interrupt is mapped to the data ready state. However the data ready
 555 // trigger will fire for both gyro and accelerometer. So it's necessary to check this register
 556 // to determine which event caused the interrupt.
 557 // When in 6.4KHz mode the interrupt is configured to be the FIFO watermark size of 6 bytes.
 558 // Since in this mode we only put gyro data in the FIFO it's sufficient to check for the FIFO
 559 // watermark reason as an idication of gyro data ready.
 560 uint8_t bmi270InterruptStatus(gyroDev_t *gyro)
 561 {
 562     return bmi270RegisterRead(&gyro->dev, BMI270_REG_INT_STATUS_1);
 563 }
 564 #endif // USE_ACCGYRO_BMI270