mirror of https://github.com/ArduPilot/ardupilot
365 lines
9.8 KiB
C++
365 lines
9.8 KiB
C++
/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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#include <FastSerial.h>
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#include "AP_InertialSensor_MPU6000.h"
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#include <SPI.h>
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#if defined(ARDUINO) && ARDUINO >= 100
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#include "Arduino.h"
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#else
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#include <wiring.h>
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#endif
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// MPU 6000 registers
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#define MPUREG_WHOAMI 0x75 //
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#define MPUREG_SMPLRT_DIV 0x19 //
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#define MPUREG_CONFIG 0x1A //
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#define MPUREG_GYRO_CONFIG 0x1B
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#define MPUREG_ACCEL_CONFIG 0x1C
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#define MPUREG_FIFO_EN 0x23
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#define MPUREG_INT_PIN_CFG 0x37
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#define MPUREG_INT_ENABLE 0x38
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#define MPUREG_INT_STATUS 0x3A
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#define MPUREG_ACCEL_XOUT_H 0x3B //
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#define MPUREG_ACCEL_XOUT_L 0x3C //
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#define MPUREG_ACCEL_YOUT_H 0x3D //
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#define MPUREG_ACCEL_YOUT_L 0x3E //
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#define MPUREG_ACCEL_ZOUT_H 0x3F //
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#define MPUREG_ACCEL_ZOUT_L 0x40 //
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#define MPUREG_TEMP_OUT_H 0x41//
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#define MPUREG_TEMP_OUT_L 0x42//
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#define MPUREG_GYRO_XOUT_H 0x43 //
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#define MPUREG_GYRO_XOUT_L 0x44 //
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#define MPUREG_GYRO_YOUT_H 0x45 //
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#define MPUREG_GYRO_YOUT_L 0x46 //
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#define MPUREG_GYRO_ZOUT_H 0x47 //
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#define MPUREG_GYRO_ZOUT_L 0x48 //
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#define MPUREG_USER_CTRL 0x6A //
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#define MPUREG_PWR_MGMT_1 0x6B //
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#define MPUREG_PWR_MGMT_2 0x6C //
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#define MPUREG_FIFO_COUNTH 0x72
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#define MPUREG_FIFO_COUNTL 0x73
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#define MPUREG_FIFO_R_W 0x74
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#define MPUREG_PRODUCT_ID 0x0C // product ID REV C = 0x14 REV D = 0x58
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// Configuration bits MPU 3000 and MPU 6000 (not revised)?
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#define BIT_SLEEP 0x40
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#define BIT_H_RESET 0x80
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#define BITS_CLKSEL 0x07
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#define MPU_CLK_SEL_PLLGYROX 0x01
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#define MPU_CLK_SEL_PLLGYROZ 0x03
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#define MPU_EXT_SYNC_GYROX 0x02
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#define BITS_FS_250DPS 0x00
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#define BITS_FS_500DPS 0x08
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#define BITS_FS_1000DPS 0x10
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#define BITS_FS_2000DPS 0x18
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#define BITS_FS_MASK 0x18
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#define BITS_DLPF_CFG_256HZ_NOLPF2 0x00
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#define BITS_DLPF_CFG_188HZ 0x01
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#define BITS_DLPF_CFG_98HZ 0x02
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#define BITS_DLPF_CFG_42HZ 0x03
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#define BITS_DLPF_CFG_20HZ 0x04
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#define BITS_DLPF_CFG_10HZ 0x05
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#define BITS_DLPF_CFG_5HZ 0x06
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#define BITS_DLPF_CFG_2100HZ_NOLPF 0x07
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#define BITS_DLPF_CFG_MASK 0x07
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#define BIT_INT_ANYRD_2CLEAR 0x10
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#define BIT_RAW_RDY_EN 0x01
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#define BIT_I2C_IF_DIS 0x10
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#define BIT_INT_STATUS_DATA 0x01
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#define MPU6000_REV_C 0x14
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#define MPU6000_REV_D 0x58
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uint8_t AP_InertialSensor_MPU6000::_cs_pin;
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/*
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RS-MPU-6000A-00.pdf, page 33, section 4.25 lists LSB sensitivity of
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gyro as 16.4 LSB/DPS at scale factor of +/- 2000dps (FS_SEL==3)
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*/
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const float AP_InertialSensor_MPU6000::_gyro_scale = (0.0174532 / 16.4);
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/*
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RS-MPU-6000A-00.pdf, page 31, section 4.23 lists LSB sensitivity of
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accel as 4096 LSB/mg at scale factor of +/- 8g (AFS_SEL==2)
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See note below about accel scaling of engineering sample MPU6k
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variants however
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*/
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const float AP_InertialSensor_MPU6000::_accel_scale = 9.81 / 4096.0;
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/* pch: I believe the accel and gyro indicies are correct
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* but somone else should please confirm.
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*/
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const uint8_t AP_InertialSensor_MPU6000::_gyro_data_index[3] = { 5, 4, 6 };
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const int8_t AP_InertialSensor_MPU6000::_gyro_data_sign[3] = { 1, 1, -1 };
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const uint8_t AP_InertialSensor_MPU6000::_accel_data_index[3] = { 1, 0, 2 };
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const int8_t AP_InertialSensor_MPU6000::_accel_data_sign[3] = { 1, 1, -1 };
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const uint8_t AP_InertialSensor_MPU6000::_temp_data_index = 3;
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static volatile uint8_t _new_data;
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static uint8_t _product_id;
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AP_InertialSensor_MPU6000::AP_InertialSensor_MPU6000( uint8_t cs_pin )
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{
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_cs_pin = cs_pin; /* can't use initializer list, is static */
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_gyro.x = 0;
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_gyro.y = 0;
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_gyro.z = 0;
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_accel.x = 0;
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_accel.y = 0;
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_accel.z = 0;
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_temp = 0;
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_initialised = 0;
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}
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void AP_InertialSensor_MPU6000::init( AP_PeriodicProcess * scheduler )
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{
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if (_initialised) return;
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_initialised = 1;
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scheduler->suspend_timer();
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hardware_init();
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scheduler->resume_timer();
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scheduler->register_process( &AP_InertialSensor_MPU6000::read );
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}
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// accumulation in ISR - must be read with interrupts disabled
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// the sum of the values since last read
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static volatile int32_t _sum[7];
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// how many values we've accumulated since last read
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static volatile uint16_t _count;
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/*================ AP_INERTIALSENSOR PUBLIC INTERFACE ==================== */
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bool AP_InertialSensor_MPU6000::update( void )
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{
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int32_t sum[7];
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uint16_t count;
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float count_scale;
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// wait for at least 1 sample
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while (_count == 0) /* nop */;
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// disable interrupts for mininum time
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cli();
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for (int i=0; i<7; i++) {
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sum[i] = _sum[i];
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_sum[i] = 0;
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}
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count = _count;
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_count = 0;
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sei();
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count_scale = 1.0 / count;
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_gyro.x = _gyro_scale * _gyro_data_sign[0] * sum[_gyro_data_index[0]] * count_scale;
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_gyro.y = _gyro_scale * _gyro_data_sign[1] * sum[_gyro_data_index[1]] * count_scale;
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_gyro.z = _gyro_scale * _gyro_data_sign[2] * sum[_gyro_data_index[2]] * count_scale;
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_accel.x = _accel_scale * _accel_data_sign[0] * sum[_accel_data_index[0]] * count_scale;
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_accel.y = _accel_scale * _accel_data_sign[1] * sum[_accel_data_index[1]] * count_scale;
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_accel.z = _accel_scale * _accel_data_sign[2] * sum[_accel_data_index[2]] * count_scale;
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_temp = _temp_to_celsius(sum[_temp_data_index] * count_scale);
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return true;
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}
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bool AP_InertialSensor_MPU6000::new_data_available( void )
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{
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return _count != 0;
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}
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float AP_InertialSensor_MPU6000::gx() { return _gyro.x; }
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float AP_InertialSensor_MPU6000::gy() { return _gyro.y; }
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float AP_InertialSensor_MPU6000::gz() { return _gyro.z; }
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void AP_InertialSensor_MPU6000::get_gyros( float * g )
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{
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g[0] = _gyro.x;
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g[1] = _gyro.y;
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g[2] = _gyro.z;
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}
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float AP_InertialSensor_MPU6000::ax() { return _accel.x; }
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float AP_InertialSensor_MPU6000::ay() { return _accel.y; }
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float AP_InertialSensor_MPU6000::az() { return _accel.z; }
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void AP_InertialSensor_MPU6000::get_accels( float * a )
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{
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a[0] = _accel.x;
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a[1] = _accel.y;
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a[2] = _accel.z;
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}
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void AP_InertialSensor_MPU6000::get_sensors( float * sensors )
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{
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sensors[0] = _gyro.x;
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sensors[1] = _gyro.y;
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sensors[2] = _gyro.z;
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sensors[3] = _accel.x;
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sensors[4] = _accel.y;
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sensors[5] = _accel.z;
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}
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float AP_InertialSensor_MPU6000::temperature() { return _temp; }
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uint32_t AP_InertialSensor_MPU6000::sample_time()
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{
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uint32_t us = micros();
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uint32_t delta = us - _last_sample_micros;
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reset_sample_time();
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return delta;
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}
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void AP_InertialSensor_MPU6000::reset_sample_time()
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{
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_last_sample_micros = micros();
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}
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/*================ HARDWARE FUNCTIONS ==================== */
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static int16_t spi_transfer_16(void)
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{
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uint8_t byte_H, byte_L;
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byte_H = SPI.transfer(0);
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byte_L = SPI.transfer(0);
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return (((int16_t)byte_H)<<8) | byte_L;
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}
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/*
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this is called from a timer interrupt to read data from the MPU6000
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and add it to _sum[]
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*/
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void AP_InertialSensor_MPU6000::read(uint32_t )
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{
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if (_new_data == 0) {
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// no new data is ready from the MPU6000
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return;
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}
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_new_data = 0;
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// now read the data
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digitalWrite(_cs_pin, LOW);
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byte addr = MPUREG_ACCEL_XOUT_H | 0x80;
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SPI.transfer(addr);
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for (uint8_t i=0; i<7; i++) {
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_sum[i] += spi_transfer_16();
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}
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_count++;
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if (_count == 0) {
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// rollover - v unlikely
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memset((void*)_sum, 0, sizeof(_sum));
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}
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digitalWrite(_cs_pin, HIGH);
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}
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uint8_t AP_InertialSensor_MPU6000::register_read( uint8_t reg )
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{
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uint8_t dump;
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uint8_t return_value;
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uint8_t addr = reg | 0x80; // Set most significant bit
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digitalWrite(_cs_pin, LOW);
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dump = SPI.transfer(addr);
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return_value = SPI.transfer(0);
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digitalWrite(_cs_pin, HIGH);
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return return_value;
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}
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void AP_InertialSensor_MPU6000::register_write(uint8_t reg, uint8_t val)
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{
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uint8_t dump;
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digitalWrite(_cs_pin, LOW);
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dump = SPI.transfer(reg);
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dump = SPI.transfer(val);
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digitalWrite(_cs_pin, HIGH);
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}
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// MPU6000 new data interrupt on INT6
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void AP_InertialSensor_MPU6000::data_interrupt(void)
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{
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// tell the timer routine that there is data to be read
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_new_data = 1;
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}
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void AP_InertialSensor_MPU6000::hardware_init()
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{
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// MPU6000 chip select setup
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pinMode(_cs_pin, OUTPUT);
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digitalWrite(_cs_pin, HIGH);
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delay(1);
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// Chip reset
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register_write(MPUREG_PWR_MGMT_1, BIT_H_RESET);
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delay(100);
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// Wake up device and select GyroZ clock (better performance)
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register_write(MPUREG_PWR_MGMT_1, MPU_CLK_SEL_PLLGYROZ);
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delay(1);
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// Disable I2C bus (recommended on datasheet)
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register_write(MPUREG_USER_CTRL, BIT_I2C_IF_DIS);
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delay(1);
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// SAMPLE RATE
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register_write(MPUREG_SMPLRT_DIV,0x04); // Sample rate = 200Hz Fsample= 1Khz/(4+1) = 200Hz
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delay(1);
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// FS & DLPF FS=2000º/s, DLPF = 98Hz (low pass filter)
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register_write(MPUREG_CONFIG, BITS_DLPF_CFG_98HZ);
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delay(1);
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register_write(MPUREG_GYRO_CONFIG,BITS_FS_2000DPS); // Gyro scale 2000º/s
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delay(1);
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_product_id = register_read(MPUREG_PRODUCT_ID); // read the product ID rev c has 1/2 the sensitivity of rev d
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//Serial.printf("Product_ID= 0x%x\n", (unsigned) _product_id);
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if (_product_id == MPU6000_REV_C) {
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// Accel scale 8g (4096 LSB/g)
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// Rev C has different scaling than rev D
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register_write(MPUREG_ACCEL_CONFIG,1<<3);
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} else {
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// Accel scale 8g (4096 LSB/g)
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register_write(MPUREG_ACCEL_CONFIG,2<<3);
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}
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delay(1);
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// INT CFG => Interrupt on Data Ready
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register_write(MPUREG_INT_ENABLE,BIT_RAW_RDY_EN); // INT: Raw data ready
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delay(1);
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register_write(MPUREG_INT_PIN_CFG,BIT_INT_ANYRD_2CLEAR); // INT: Clear on any read
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delay(1);
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// Oscillator set
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// register_write(MPUREG_PWR_MGMT_1,MPU_CLK_SEL_PLLGYROZ);
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delay(1);
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attachInterrupt(6,data_interrupt,RISING);
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}
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float AP_InertialSensor_MPU6000::_temp_to_celsius ( uint16_t regval )
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{
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/* TODO */
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return 20.0;
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}
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// return the MPU6k gyro drift rate in radian/s/s
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// note that this is much better than the oilpan gyros
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float AP_InertialSensor_MPU6000::get_gyro_drift_rate(void)
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{
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// 0.5 degrees/second/minute
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return ToRad(0.5/60);
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}
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