Ardupilot2/libraries/AP_InertialSensor/AP_InertialSensor_MPU6000.cpp
Víctor Mayoral Vilches 3379ddd51f AP_InertialSensor_MPU6000: Add _register_write_check method.
This private method allows to check whether the value written and
the posterior value readed are the same.
Should be used only for debuging purposes, for release versions use
_register_write instead.
2014-07-14 09:44:33 +10:00

614 lines
25 KiB
C++

/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
#include <AP_HAL.h>
#include "AP_InertialSensor_MPU6000.h"
#include "../AP_HAL_Linux/GPIO.h"
extern const AP_HAL::HAL& hal;
// MPU6000 accelerometer scaling
#define MPU6000_ACCEL_SCALE_1G (GRAVITY_MSS / 4096.0f)
// 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),
_initialised(false),
_mpu6000_product_id(AP_PRODUCT_ID_NONE)
{
}
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();
_drdy_pin = hal.gpio->channel(BBB_P8_14);
// For some reason configuring the pin as an input make the driver fail
//_drdy_pin->mode(GPIO_IN);
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;
}