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ardupilot/libraries/AP_InertialSensor/AP_InertialSensor_MPU6000.cpp

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/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
#include <AP_HAL.h>
#include "AP_InertialSensor_MPU6000.h"
extern const AP_HAL::HAL& hal;
// MPU6000 accelerometer scaling
#define MPU6000_ACCEL_SCALE_1G (GRAVITY_MSS / 4096.0f)
#if CONFIG_HAL_BOARD == HAL_BOARD_APM2
#define MPU6000_DRDY_PIN 70
#elif CONFIG_HAL_BOARD == HAL_BOARD_LINUX
#if CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_ERLE || CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_PXF
#include "../AP_HAL_Linux/GPIO.h"
#define MPU6000_DRDY_PIN BBB_P8_14
#endif
#endif
// MPU 6000 registers
#define MPUREG_XG_OFFS_TC 0x00
#define MPUREG_YG_OFFS_TC 0x01
#define MPUREG_ZG_OFFS_TC 0x02
#define MPUREG_X_FINE_GAIN 0x03
#define MPUREG_Y_FINE_GAIN 0x04
#define MPUREG_Z_FINE_GAIN 0x05
#define MPUREG_XA_OFFS_H 0x06 // X axis accelerometer offset (high byte)
#define MPUREG_XA_OFFS_L 0x07 // X axis accelerometer offset (low byte)
#define MPUREG_YA_OFFS_H 0x08 // Y axis accelerometer offset (high byte)
#define MPUREG_YA_OFFS_L 0x09 // Y axis accelerometer offset (low byte)
#define MPUREG_ZA_OFFS_H 0x0A // Z axis accelerometer offset (high byte)
#define MPUREG_ZA_OFFS_L 0x0B // Z axis accelerometer offset (low byte)
#define MPUREG_PRODUCT_ID 0x0C // Product ID Register
#define MPUREG_XG_OFFS_USRH 0x13 // X axis gyro offset (high byte)
#define MPUREG_XG_OFFS_USRL 0x14 // X axis gyro offset (low byte)
#define MPUREG_YG_OFFS_USRH 0x15 // Y axis gyro offset (high byte)
#define MPUREG_YG_OFFS_USRL 0x16 // Y axis gyro offset (low byte)
#define MPUREG_ZG_OFFS_USRH 0x17 // Z axis gyro offset (high byte)
#define MPUREG_ZG_OFFS_USRL 0x18 // Z axis gyro offset (low byte)
#define MPUREG_SMPLRT_DIV 0x19 // sample rate. Fsample= 1Khz/(<this value>+1) = 200Hz
# define MPUREG_SMPLRT_1000HZ 0x00
# define MPUREG_SMPLRT_500HZ 0x01
# define MPUREG_SMPLRT_250HZ 0x03
# define MPUREG_SMPLRT_200HZ 0x04
# define MPUREG_SMPLRT_100HZ 0x09
# define MPUREG_SMPLRT_50HZ 0x13
#define MPUREG_CONFIG 0x1A
#define MPUREG_GYRO_CONFIG 0x1B
// bit definitions for MPUREG_GYRO_CONFIG
# define BITS_GYRO_FS_250DPS 0x00
# define BITS_GYRO_FS_500DPS 0x08
# define BITS_GYRO_FS_1000DPS 0x10
# define BITS_GYRO_FS_2000DPS 0x18
# define BITS_GYRO_FS_MASK 0x18 // only bits 3 and 4 are used for gyro full scale so use this to mask off other bits
# define BITS_GYRO_ZGYRO_SELFTEST 0x20
# define BITS_GYRO_YGYRO_SELFTEST 0x40
# define BITS_GYRO_XGYRO_SELFTEST 0x80
#define MPUREG_ACCEL_CONFIG 0x1C
#define MPUREG_MOT_THR 0x1F // detection threshold for Motion interrupt generation. Motion is detected when the absolute value of any of the accelerometer measurements exceeds this
#define MPUREG_MOT_DUR 0x20 // duration counter threshold for Motion interrupt generation. The duration counter ticks at 1 kHz, therefore MOT_DUR has a unit of 1 LSB = 1 ms
#define MPUREG_ZRMOT_THR 0x21 // detection threshold for Zero Motion interrupt generation.
#define MPUREG_ZRMOT_DUR 0x22 // duration counter threshold for Zero Motion interrupt generation. The duration counter ticks at 16 Hz, therefore ZRMOT_DUR has a unit of 1 LSB = 64 ms.
#define MPUREG_FIFO_EN 0x23
#define MPUREG_INT_PIN_CFG 0x37
# define BIT_INT_RD_CLEAR 0x10 // clear the interrupt when any read occurs
# define BIT_LATCH_INT_EN 0x20 // latch data ready pin
#define MPUREG_INT_ENABLE 0x38
// bit definitions for MPUREG_INT_ENABLE
# define BIT_RAW_RDY_EN 0x01
# define BIT_DMP_INT_EN 0x02 // enabling this bit (DMP_INT_EN) also enables RAW_RDY_EN it seems
# define BIT_UNKNOWN_INT_EN 0x04
# define BIT_I2C_MST_INT_EN 0x08
# define BIT_FIFO_OFLOW_EN 0x10
# define BIT_ZMOT_EN 0x20
# define BIT_MOT_EN 0x40
# define BIT_FF_EN 0x80
#define MPUREG_INT_STATUS 0x3A
// bit definitions for MPUREG_INT_STATUS (same bit pattern as above because this register shows what interrupt actually fired)
# define BIT_RAW_RDY_INT 0x01
# define BIT_DMP_INT 0x02
# define BIT_UNKNOWN_INT 0x04
# define BIT_I2C_MST_INT 0x08
# define BIT_FIFO_OFLOW_INT 0x10
# define BIT_ZMOT_INT 0x20
# define BIT_MOT_INT 0x40
# define BIT_FF_INT 0x80
#define MPUREG_ACCEL_XOUT_H 0x3B
#define MPUREG_ACCEL_XOUT_L 0x3C
#define MPUREG_ACCEL_YOUT_H 0x3D
#define MPUREG_ACCEL_YOUT_L 0x3E
#define MPUREG_ACCEL_ZOUT_H 0x3F
#define MPUREG_ACCEL_ZOUT_L 0x40
#define MPUREG_TEMP_OUT_H 0x41
#define MPUREG_TEMP_OUT_L 0x42
#define MPUREG_GYRO_XOUT_H 0x43
#define MPUREG_GYRO_XOUT_L 0x44
#define MPUREG_GYRO_YOUT_H 0x45
#define MPUREG_GYRO_YOUT_L 0x46
#define MPUREG_GYRO_ZOUT_H 0x47
#define MPUREG_GYRO_ZOUT_L 0x48
#define MPUREG_USER_CTRL 0x6A
// bit definitions for MPUREG_USER_CTRL
# define BIT_USER_CTRL_SIG_COND_RESET 0x01 // resets signal paths and results registers for all sensors (gyros, accel, temp)
# define BIT_USER_CTRL_I2C_MST_RESET 0x02 // reset I2C Master (only applicable if I2C_MST_EN bit is set)
# define BIT_USER_CTRL_FIFO_RESET 0x04 // Reset (i.e. clear) FIFO buffer
# define BIT_USER_CTRL_DMP_RESET 0x08 // Reset DMP
# define BIT_USER_CTRL_I2C_IF_DIS 0x10 // Disable primary I2C interface and enable hal.spi->interface
# define BIT_USER_CTRL_I2C_MST_EN 0x20 // Enable MPU to act as the I2C Master to external slave sensors
# define BIT_USER_CTRL_FIFO_EN 0x40 // Enable FIFO operations
# define BIT_USER_CTRL_DMP_EN 0x80 // Enable DMP operations
#define MPUREG_PWR_MGMT_1 0x6B
# define BIT_PWR_MGMT_1_CLK_INTERNAL 0x00 // clock set to internal 8Mhz oscillator
# define BIT_PWR_MGMT_1_CLK_XGYRO 0x01 // PLL with X axis gyroscope reference
# define BIT_PWR_MGMT_1_CLK_YGYRO 0x02 // PLL with Y axis gyroscope reference
# define BIT_PWR_MGMT_1_CLK_ZGYRO 0x03 // PLL with Z axis gyroscope reference
# define BIT_PWR_MGMT_1_CLK_EXT32KHZ 0x04 // PLL with external 32.768kHz reference
# define BIT_PWR_MGMT_1_CLK_EXT19MHZ 0x05 // PLL with external 19.2MHz reference
# define BIT_PWR_MGMT_1_CLK_STOP 0x07 // Stops the clock and keeps the timing generator in reset
# define BIT_PWR_MGMT_1_TEMP_DIS 0x08 // disable temperature sensor
# define BIT_PWR_MGMT_1_CYCLE 0x20 // put sensor into cycle mode. cycles between sleep mode and waking up to take a single sample of data from active sensors at a rate determined by LP_WAKE_CTRL
# define BIT_PWR_MGMT_1_SLEEP 0x40 // put sensor into low power sleep mode
# define BIT_PWR_MGMT_1_DEVICE_RESET 0x80 // reset entire device
#define MPUREG_PWR_MGMT_2 0x6C // allows the user to configure the frequency of wake-ups in Accelerometer Only Low Power Mode
#define MPUREG_BANK_SEL 0x6D // DMP bank selection register (used to indirectly access DMP registers)
#define MPUREG_MEM_START_ADDR 0x6E // DMP memory start address (used to indirectly write to dmp memory)
#define MPUREG_MEM_R_W 0x6F // DMP related register
#define MPUREG_DMP_CFG_1 0x70 // DMP related register
#define MPUREG_DMP_CFG_2 0x71 // DMP related register
#define MPUREG_FIFO_COUNTH 0x72
#define MPUREG_FIFO_COUNTL 0x73
#define MPUREG_FIFO_R_W 0x74
#define MPUREG_WHOAMI 0x75
// Configuration bits MPU 3000 and MPU 6000 (not revised)?
#define BITS_DLPF_CFG_256HZ_NOLPF2 0x00
#define BITS_DLPF_CFG_188HZ 0x01
#define BITS_DLPF_CFG_98HZ 0x02
#define BITS_DLPF_CFG_42HZ 0x03
#define BITS_DLPF_CFG_20HZ 0x04
#define BITS_DLPF_CFG_10HZ 0x05
#define BITS_DLPF_CFG_5HZ 0x06
#define BITS_DLPF_CFG_2100HZ_NOLPF 0x07
#define BITS_DLPF_CFG_MASK 0x07
// Product ID Description for MPU6000
// high 4 bits low 4 bits
// Product Name Product Revision
#define MPU6000ES_REV_C4 0x14 // 0001 0100
#define MPU6000ES_REV_C5 0x15 // 0001 0101
#define MPU6000ES_REV_D6 0x16 // 0001 0110
#define MPU6000ES_REV_D7 0x17 // 0001 0111
#define MPU6000ES_REV_D8 0x18 // 0001 1000
#define MPU6000_REV_C4 0x54 // 0101 0100
#define MPU6000_REV_C5 0x55 // 0101 0101
#define MPU6000_REV_D6 0x56 // 0101 0110
#define MPU6000_REV_D7 0x57 // 0101 0111
#define MPU6000_REV_D8 0x58 // 0101 1000
#define MPU6000_REV_D9 0x59 // 0101 1001
/*
* RM-MPU-6000A-00.pdf, page 33, section 4.25 lists LSB sensitivity of
* gyro as 16.4 LSB/DPS at scale factor of +/- 2000dps (FS_SEL==3)
*/
const float AP_InertialSensor_MPU6000::_gyro_scale = (0.0174532f / 16.4f);
/*
* RM-MPU-6000A-00.pdf, page 31, section 4.23 lists LSB sensitivity of
* accel as 4096 LSB/mg at scale factor of +/- 8g (AFS_SEL==2)
*
* See note below about accel scaling of engineering sample MPU6k
* variants however
*/
AP_InertialSensor_MPU6000::AP_InertialSensor_MPU6000() :
AP_InertialSensor(),
_drdy_pin(NULL),
_spi(NULL),
_spi_sem(NULL),
_num_samples(0),
_last_sample_time_micros(0),
_initialised(false),
_mpu6000_product_id(AP_PRODUCT_ID_NONE),
_sample_shift(0),
_last_filter_hz(0),
_error_count(0)
{
}
uint16_t AP_InertialSensor_MPU6000::_init_sensor( Sample_rate sample_rate )
{
if (_initialised) return _mpu6000_product_id;
_initialised = true;
_spi = hal.spi->device(AP_HAL::SPIDevice_MPU6000);
_spi_sem = _spi->get_semaphore();
#ifdef MPU6000_DRDY_PIN
_drdy_pin = hal.gpio->channel(MPU6000_DRDY_PIN);
_drdy_pin->mode(HAL_GPIO_INPUT);
#endif
hal.scheduler->suspend_timer_procs();
uint8_t tries = 0;
do {
bool success = _hardware_init(sample_rate);
if (success) {
hal.scheduler->delay(5+2);
if (!_spi_sem->take(100)) {
hal.scheduler->panic(PSTR("MPU6000: Unable to get semaphore"));
}
if (_data_ready()) {
_spi_sem->give();
break;
} else {
hal.console->println_P(
PSTR("MPU6000 startup failed: no data ready"));
}
_spi_sem->give();
}
if (tries++ > 5) {
hal.scheduler->panic(PSTR("PANIC: failed to boot MPU6000 5 times"));
}
} while (1);
hal.scheduler->resume_timer_procs();
/* read the first lot of data.
* _read_data_transaction requires the spi semaphore to be taken by
* its caller. */
_last_sample_time_micros = hal.scheduler->micros();
hal.scheduler->delay(10);
if (_spi_sem->take(100)) {
_read_data_transaction();
_spi_sem->give();
}
// start the timer process to read samples
hal.scheduler->register_timer_process(AP_HAL_MEMBERPROC(&AP_InertialSensor_MPU6000::_poll_data));
#if MPU6000_DEBUG
_dump_registers();
#endif
return _mpu6000_product_id;
}
/*================ AP_INERTIALSENSOR PUBLIC INTERFACE ==================== */
bool AP_InertialSensor_MPU6000::wait_for_sample(uint16_t timeout_ms)
{
if (_sample_available()) {
return true;
}
uint32_t start = hal.scheduler->millis();
while ((hal.scheduler->millis() - start) < timeout_ms) {
hal.scheduler->delay_microseconds(100);
if (_sample_available()) {
return true;
}
}
return false;
}
bool AP_InertialSensor_MPU6000::update( void )
{
// wait for at least 1 sample
if (!wait_for_sample(1000)) {
return false;
}
_previous_accel[0] = _accel[0];
// disable timer procs for mininum time
hal.scheduler->suspend_timer_procs();
_gyro[0] = Vector3f(_gyro_sum.x, _gyro_sum.y, _gyro_sum.z);
_accel[0] = Vector3f(_accel_sum.x, _accel_sum.y, _accel_sum.z);
_num_samples = _sum_count;
_accel_sum.zero();
_gyro_sum.zero();
_sum_count = 0;
hal.scheduler->resume_timer_procs();
_gyro[0].rotate(_board_orientation);
_gyro[0] *= _gyro_scale / _num_samples;
_gyro[0] -= _gyro_offset[0];
_accel[0].rotate(_board_orientation);
_accel[0] *= MPU6000_ACCEL_SCALE_1G / _num_samples;
Vector3f accel_scale = _accel_scale[0].get();
_accel[0].x *= accel_scale.x;
_accel[0].y *= accel_scale.y;
_accel[0].z *= accel_scale.z;
_accel[0] -= _accel_offset[0];
if (_last_filter_hz != _mpu6000_filter) {
if (_spi_sem->take(10)) {
_spi->set_bus_speed(AP_HAL::SPIDeviceDriver::SPI_SPEED_LOW);
_set_filter_register(_mpu6000_filter, 0);
_spi->set_bus_speed(AP_HAL::SPIDeviceDriver::SPI_SPEED_HIGH);
_error_count = 0;
_spi_sem->give();
}
}
return true;
}
/*================ HARDWARE FUNCTIONS ==================== */
/**
* Return true if the MPU6000 has new data available for reading.
*
* We use the data ready pin if it is available. Otherwise, read the
* status register.
*/
bool AP_InertialSensor_MPU6000::_data_ready()
{
if (_drdy_pin) {
return _drdy_pin->read() != 0;
}
uint8_t status = _register_read(MPUREG_INT_STATUS);
return (status & BIT_RAW_RDY_INT) != 0;
}
/**
* Timer process to poll for new data from the MPU6000.
*/
void AP_InertialSensor_MPU6000::_poll_data(void)
{
if (hal.scheduler->in_timerprocess()) {
if (!_spi_sem->take_nonblocking()) {
/*
the semaphore being busy is an expected condition when the
mainline code is calling wait_for_sample() which will
grab the semaphore. We return now and rely on the mainline
code grabbing the latest sample.
*/
return;
}
if (_data_ready()) {
_last_sample_time_micros = hal.scheduler->micros();
_read_data_transaction();
}
_spi_sem->give();
} else {
/* Synchronous read - take semaphore */
if (_spi_sem->take(10)) {
if (_data_ready()) {
_last_sample_time_micros = hal.scheduler->micros();
_read_data_transaction();
}
_spi_sem->give();
} else {
hal.scheduler->panic(
PSTR("PANIC: AP_InertialSensor_MPU6000::_poll_data "
"failed to take SPI semaphore synchronously"));
}
}
}
void AP_InertialSensor_MPU6000::_read_data_transaction() {
/* one resister address followed by seven 2-byte registers */
struct PACKED {
uint8_t cmd;
uint8_t int_status;
uint8_t v[14];
} rx, tx = { cmd : MPUREG_INT_STATUS | 0x80, };
_spi->transaction((const uint8_t *)&tx, (uint8_t *)&rx, sizeof(rx));
/*
detect a bad SPI bus transaction by looking for all 14 bytes
zero, or the wrong INT_STATUS register value. This is used to
detect a too high SPI bus speed.
*/
uint8_t i;
for (i=0; i<14; i++) {
if (rx.v[i] != 0) break;
}
if ((rx.int_status&~0x6) != (_drdy_pin==NULL?0:BIT_RAW_RDY_INT) || i == 14) {
// likely a bad bus transaction
if (++_error_count > 4) {
_spi->set_bus_speed(AP_HAL::SPIDeviceDriver::SPI_SPEED_LOW);
}
}
#define int16_val(v, idx) ((int16_t)(((uint16_t)v[2*idx] << 8) | v[2*idx+1]))
_accel_sum.x += int16_val(rx.v, 1);
_accel_sum.y += int16_val(rx.v, 0);
_accel_sum.z -= int16_val(rx.v, 2);
_gyro_sum.x += int16_val(rx.v, 5);
_gyro_sum.y += int16_val(rx.v, 4);
_gyro_sum.z -= int16_val(rx.v, 6);
_sum_count++;
if (_sum_count == 0) {
// rollover - v unlikely
_accel_sum.zero();
_gyro_sum.zero();
}
}
uint8_t AP_InertialSensor_MPU6000::_register_read( uint8_t reg )
{
uint8_t addr = reg | 0x80; // Set most significant bit
uint8_t tx[2];
uint8_t rx[2];
tx[0] = addr;
tx[1] = 0;
_spi->transaction(tx, rx, 2);
return rx[1];
}
void AP_InertialSensor_MPU6000::_register_write(uint8_t reg, uint8_t val)
{
uint8_t tx[2];
uint8_t rx[2];
tx[0] = reg;
tx[1] = val;
_spi->transaction(tx, rx, 2);
}
/*
useful when debugging SPI bus errors
*/
void AP_InertialSensor_MPU6000::_register_write_check(uint8_t reg, uint8_t val)
{
uint8_t readed;
_register_write(reg, val);
readed = _register_read(reg);
if (readed != val){
hal.console->printf_P(PSTR("Values doesn't match; written: %02x; read: %02x "), val, readed);
}
#if MPU6000_DEBUG
hal.console->printf_P(PSTR("Values written: %02x; readed: %02x "), val, readed);
#endif
}
/*
set the DLPF filter frequency. Assumes caller has taken semaphore
*/
void AP_InertialSensor_MPU6000::_set_filter_register(uint8_t filter_hz, uint8_t default_filter)
{
uint8_t filter = default_filter;
// choose filtering frequency
switch (filter_hz) {
case 5:
filter = BITS_DLPF_CFG_5HZ;
break;
case 10:
filter = BITS_DLPF_CFG_10HZ;
break;
case 20:
filter = BITS_DLPF_CFG_20HZ;
break;
case 42:
filter = BITS_DLPF_CFG_42HZ;
break;
case 98:
filter = BITS_DLPF_CFG_98HZ;
break;
}
if (filter != 0) {
_last_filter_hz = filter_hz;
_register_write(MPUREG_CONFIG, filter);
}
}
bool AP_InertialSensor_MPU6000::_hardware_init(Sample_rate sample_rate)
{
if (!_spi_sem->take(100)) {
hal.scheduler->panic(PSTR("MPU6000: Unable to get semaphore"));
}
// initially run the bus at low speed (500kHz on APM2)
_spi->set_bus_speed(AP_HAL::SPIDeviceDriver::SPI_SPEED_LOW);
// Chip reset
uint8_t tries;
for (tries = 0; tries<5; tries++) {
_register_write(MPUREG_PWR_MGMT_1, BIT_PWR_MGMT_1_DEVICE_RESET);
hal.scheduler->delay(100);
// Wake up device and select GyroZ clock. Note that the
// MPU6000 starts up in sleep mode, and it can take some time
// for it to come out of sleep
_register_write(MPUREG_PWR_MGMT_1, BIT_PWR_MGMT_1_CLK_ZGYRO);
hal.scheduler->delay(5);
// check it has woken up
if (_register_read(MPUREG_PWR_MGMT_1) == BIT_PWR_MGMT_1_CLK_ZGYRO) {
break;
}
#if MPU6000_DEBUG
_dump_registers();
#endif
}
if (tries == 5) {
hal.console->println_P(PSTR("Failed to boot MPU6000 5 times"));
_spi_sem->give();
return false;
}
_register_write(MPUREG_PWR_MGMT_2, 0x00); // only used for wake-up in accelerometer only low power mode
hal.scheduler->delay(1);
// Disable I2C bus (recommended on datasheet)
_register_write(MPUREG_USER_CTRL, BIT_USER_CTRL_I2C_IF_DIS);
hal.scheduler->delay(1);
uint8_t default_filter;
// sample rate and filtering
// to minimise the effects of aliasing we choose a filter
// that is less than half of the sample rate
switch (sample_rate) {
case RATE_50HZ:
// this is used for plane and rover, where noise resistance is
// more important than update rate. Tests on an aerobatic plane
// show that 10Hz is fine, and makes it very noise resistant
default_filter = BITS_DLPF_CFG_10HZ;
_sample_shift = 2;
break;
case RATE_100HZ:
default_filter = BITS_DLPF_CFG_20HZ;
_sample_shift = 1;
break;
case RATE_200HZ:
default:
default_filter = BITS_DLPF_CFG_20HZ;
_sample_shift = 0;
break;
}
_set_filter_register(_mpu6000_filter, default_filter);
// set sample rate to 200Hz, and use _sample_divider to give
// the requested rate to the application
_register_write(MPUREG_SMPLRT_DIV, MPUREG_SMPLRT_200HZ);
hal.scheduler->delay(1);
_register_write(MPUREG_GYRO_CONFIG, BITS_GYRO_FS_2000DPS); // Gyro scale 2000º/s
hal.scheduler->delay(1);
// read the product ID rev c has 1/2 the sensitivity of rev d
_mpu6000_product_id = _register_read(MPUREG_PRODUCT_ID);
//Serial.printf("Product_ID= 0x%x\n", (unsigned) _mpu6000_product_id);
if ((_mpu6000_product_id == MPU6000ES_REV_C4) || (_mpu6000_product_id == MPU6000ES_REV_C5) ||
(_mpu6000_product_id == MPU6000_REV_C4) || (_mpu6000_product_id == MPU6000_REV_C5)) {
// Accel scale 8g (4096 LSB/g)
// Rev C has different scaling than rev D
_register_write(MPUREG_ACCEL_CONFIG,1<<3);
} else {
// Accel scale 8g (4096 LSB/g)
_register_write(MPUREG_ACCEL_CONFIG,2<<3);
}
hal.scheduler->delay(1);
// configure interrupt to fire when new data arrives
_register_write(MPUREG_INT_ENABLE, BIT_RAW_RDY_EN);
hal.scheduler->delay(1);
// clear interrupt on any read, and hold the data ready pin high
// until we clear the interrupt
_register_write(MPUREG_INT_PIN_CFG, BIT_INT_RD_CLEAR | BIT_LATCH_INT_EN);
// now that we have initialised, we set the SPI bus speed to high
// (8MHz on APM2)
_spi->set_bus_speed(AP_HAL::SPIDeviceDriver::SPI_SPEED_HIGH);
_spi_sem->give();
return true;
}
// return the MPU6k gyro drift rate in radian/s/s
// note that this is much better than the oilpan gyros
float AP_InertialSensor_MPU6000::get_gyro_drift_rate(void)
{
// 0.5 degrees/second/minute
return ToRad(0.5/60);
}
// return true if a sample is available
bool AP_InertialSensor_MPU6000::_sample_available()
{
_poll_data();
return (_sum_count >> _sample_shift) > 0;
}
#if MPU6000_DEBUG
// dump all config registers - used for debug
void AP_InertialSensor_MPU6000::_dump_registers(void)
{
hal.console->println_P(PSTR("MPU6000 registers"));
if (_spi_sem->take(100)) {
for (uint8_t reg=MPUREG_PRODUCT_ID; reg<=108; reg++) {
uint8_t v = _register_read(reg);
hal.console->printf_P(PSTR("%02x:%02x "), (unsigned)reg, (unsigned)v);
if ((reg - (MPUREG_PRODUCT_ID-1)) % 16 == 0) {
hal.console->println();
}
}
hal.console->println();
_spi_sem->give();
}
}
#endif
// get_delta_time returns the time period in seconds overwhich the sensor data was collected
float AP_InertialSensor_MPU6000::get_delta_time() const
{
// the sensor runs at 200Hz
return 0.005 * _num_samples;
}
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