mirror of https://github.com/ArduPilot/ardupilot
221 lines
9.1 KiB
C++
221 lines
9.1 KiB
C++
/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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Flymaple IMU driver by Mike McCauley
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*/
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// Interface to the Flymaple sensors:
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// ITG3205 Gyroscope http://www.sparkfun.com/datasheets/Sensors/Gyro/PS-ITG-3200-00-01.4.pdf
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// ADXL345 Accelerometer http://www.analog.com/static/imported-files/data_sheets/ADXL345.pdf
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#include <AP_HAL/AP_HAL.h>
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#if CONFIG_HAL_BOARD == HAL_BOARD_FLYMAPLE
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#include "AP_InertialSensor_Flymaple.h"
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const extern AP_HAL::HAL& hal;
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// This is how often we wish to make raw samples of the sensors in Hz
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const uint32_t raw_sample_rate_hz = 800;
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// And the equivalent time between samples in microseconds
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const uint32_t raw_sample_interval_us = (1000000 / raw_sample_rate_hz);
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///////
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/// Accelerometer ADXL345 register definitions
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#define FLYMAPLE_ACCELEROMETER_ADDRESS 0x53
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#define FLYMAPLE_ACCELEROMETER_XL345_DEVID 0xe5
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#define FLYMAPLE_ACCELEROMETER_ADXLREG_BW_RATE 0x2c
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#define FLYMAPLE_ACCELEROMETER_ADXLREG_POWER_CTL 0x2d
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#define FLYMAPLE_ACCELEROMETER_ADXLREG_DATA_FORMAT 0x31
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#define FLYMAPLE_ACCELEROMETER_ADXLREG_DEVID 0x00
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#define FLYMAPLE_ACCELEROMETER_ADXLREG_DATAX0 0x32
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#define FLYMAPLE_ACCELEROMETER_GRAVITY 248
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// ADXL345 accelerometer scaling
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// Result will be scaled to 1m/s/s
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// ADXL345 in Full resolution mode (any g scaling) is 256 counts/g, so scale by 9.81/256 = 0.038320312
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#define FLYMAPLE_ACCELEROMETER_SCALE_M_S (GRAVITY_MSS / 256.0f)
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/// Gyro ITG3205 register definitions
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#define FLYMAPLE_GYRO_ADDRESS 0x68
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#define FLYMAPLE_GYRO_WHO_AM_I 0x00
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#define FLYMAPLE_GYRO_PWR_MGM 0x3e
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#define FLYMAPLE_GYRO_DLPF_FS 0x16
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#define FLYMAPLE_GYRO_INT_CFG 0x17
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#define FLYMAPLE_GYRO_SMPLRT_DIV 0x15
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#define FLYMAPLE_GYRO_GYROX_H 0x1d
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// ITG3200 Gyroscope scaling
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// ITG3200 is 14.375 LSB degrees/sec with FS_SEL=3
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// Result wil be radians/sec
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#define FLYMAPLE_GYRO_SCALE_R_S (1.0f / 14.375f) * (3.1415926f / 180.0f)
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AP_InertialSensor_Flymaple::AP_InertialSensor_Flymaple(AP_InertialSensor &imu) :
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AP_InertialSensor_Backend(imu)
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{}
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/*
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detect the sensor
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*/
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AP_InertialSensor_Backend *AP_InertialSensor_Flymaple::detect(AP_InertialSensor &_imu)
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{
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AP_InertialSensor_Flymaple *sensor = new AP_InertialSensor_Flymaple(_imu);
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if (sensor == NULL) {
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return NULL;
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}
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if (!sensor->_init_sensor()) {
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delete sensor;
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return NULL;
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}
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return sensor;
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}
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bool AP_InertialSensor_Flymaple::_init_sensor(void)
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{
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// get pointer to i2c bus semaphore
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AP_HAL::Semaphore* i2c_sem = hal.i2c->get_semaphore();
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// take i2c bus sempahore
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if (!i2c_sem->take(HAL_SEMAPHORE_BLOCK_FOREVER))
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return false;
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// Init the accelerometer
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uint8_t data;
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hal.i2c->readRegister(FLYMAPLE_ACCELEROMETER_ADDRESS, FLYMAPLE_ACCELEROMETER_ADXLREG_DEVID, &data);
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if (data != FLYMAPLE_ACCELEROMETER_XL345_DEVID)
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AP_HAL::panic("AP_InertialSensor_Flymaple: could not find ADXL345 accelerometer sensor");
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hal.i2c->writeRegister(FLYMAPLE_ACCELEROMETER_ADDRESS, FLYMAPLE_ACCELEROMETER_ADXLREG_POWER_CTL, 0x00);
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hal.scheduler->delay(5);
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hal.i2c->writeRegister(FLYMAPLE_ACCELEROMETER_ADDRESS, FLYMAPLE_ACCELEROMETER_ADXLREG_POWER_CTL, 0xff);
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hal.scheduler->delay(5);
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// Measure mode:
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hal.i2c->writeRegister(FLYMAPLE_ACCELEROMETER_ADDRESS, FLYMAPLE_ACCELEROMETER_ADXLREG_POWER_CTL, 0x08);
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hal.scheduler->delay(5);
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// Full resolution, 8g:
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// Caution, this must agree with FLYMAPLE_ACCELEROMETER_SCALE_1G
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// In full resoution mode, the scale factor need not change
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hal.i2c->writeRegister(FLYMAPLE_ACCELEROMETER_ADDRESS, FLYMAPLE_ACCELEROMETER_ADXLREG_DATA_FORMAT, 0x08);
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hal.scheduler->delay(5);
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// Normal power, 800Hz Output Data Rate, 400Hz bandwidth:
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hal.i2c->writeRegister(FLYMAPLE_ACCELEROMETER_ADDRESS, FLYMAPLE_ACCELEROMETER_ADXLREG_BW_RATE, 0x0d);
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hal.scheduler->delay(5);
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// Power up default is FIFO bypass mode. FIFO is not used by the chip
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// Init the Gyro
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// Expect to read the same as the Gyro I2C adress:
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hal.i2c->readRegister(FLYMAPLE_GYRO_ADDRESS, FLYMAPLE_GYRO_WHO_AM_I, &data);
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if (data != FLYMAPLE_GYRO_ADDRESS)
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AP_HAL::panic("AP_InertialSensor_Flymaple: could not find ITG-3200 accelerometer sensor");
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hal.i2c->writeRegister(FLYMAPLE_GYRO_ADDRESS, FLYMAPLE_GYRO_PWR_MGM, 0x00);
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hal.scheduler->delay(1);
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// Sample rate divider: with 8kHz internal clock (see FLYMAPLE_GYRO_DLPF_FS),
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// get 500Hz sample rate, 2 samples
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hal.i2c->writeRegister(FLYMAPLE_GYRO_ADDRESS, FLYMAPLE_GYRO_SMPLRT_DIV, 0x0f);
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hal.scheduler->delay(1);
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// 2000 degrees/sec, 256Hz LPF, 8kHz internal sample rate
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// This is the least amount of filtering we can configure for this device
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hal.i2c->writeRegister(FLYMAPLE_GYRO_ADDRESS, FLYMAPLE_GYRO_DLPF_FS, 0x18);
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hal.scheduler->delay(1);
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// No interrupts
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hal.i2c->writeRegister(FLYMAPLE_GYRO_ADDRESS, FLYMAPLE_GYRO_INT_CFG, 0x00);
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hal.scheduler->delay(1);
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// give back i2c semaphore
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i2c_sem->give();
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_gyro_instance = _imu.register_gyro(raw_sample_rate_hz);
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_accel_instance = _imu.register_accel(raw_sample_rate_hz);
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_product_id = AP_PRODUCT_ID_FLYMAPLE;
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return true;
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}
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// This takes about 20us to run
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bool AP_InertialSensor_Flymaple::update(void)
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{
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update_accel(_accel_instance);
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update_gyro(_gyro_instance);
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return true;
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}
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// This needs to get called as often as possible.
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// Its job is to accumulate samples as fast as is reasonable for the accel and gyro
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// sensors.
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// Note that this is called from gyro_sample_available() and
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// accel_sample_available(), which is really not good enough for
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// 800Hz, as it is common for the main loop to take more than 1.5ms
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// before wait_for_sample() is called again. We can't just call this
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// from a timer as timers run with interrupts disabled, and the I2C
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// operations take too long
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// So we are stuck with a suboptimal solution. The results are not so
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// good in terms of timing. It may be better with the FIFOs enabled
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void AP_InertialSensor_Flymaple::accumulate(void)
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{
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// get pointer to i2c bus semaphore
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AP_HAL::Semaphore* i2c_sem = hal.i2c->get_semaphore();
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// take i2c bus sempahore
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if (!i2c_sem->take(HAL_SEMAPHORE_BLOCK_FOREVER))
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return;
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// Read accelerometer
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// ADXL345 is in the default FIFO bypass mode, so the FIFO is not used
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uint8_t buffer[6];
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uint32_t now = AP_HAL::micros();
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// This takes about 250us at 400kHz I2C speed
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if ((now - _last_accel_timestamp) >= raw_sample_interval_us
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&& hal.i2c->readRegisters(FLYMAPLE_ACCELEROMETER_ADDRESS, FLYMAPLE_ACCELEROMETER_ADXLREG_DATAX0, 6, buffer) == 0)
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{
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// The order is a bit wierd here since the standard we have adopted for Flymaple
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// sensor orientation is different to what the board designers intended
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// Caution, to support alternative chip orientations on other bords, may
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// need to add a chip orientation rotate
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int16_t y = -((((int16_t)buffer[1]) << 8) | buffer[0]); // chip X axis
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int16_t x = -((((int16_t)buffer[3]) << 8) | buffer[2]); // chip Y axis
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int16_t z = -((((int16_t)buffer[5]) << 8) | buffer[4]); // chip Z axis
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Vector3f accel = Vector3f(x,y,z);
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// Adjust for chip scaling to get m/s/s
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accel *= FLYMAPLE_ACCELEROMETER_SCALE_M_S;
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_rotate_and_correct_accel(_accel_instance, accel);
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_notify_new_accel_raw_sample(_accel_instance, accel);
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_last_accel_timestamp = now;
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}
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// Read gyro
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now = AP_HAL::micros();
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// This takes about 250us at 400kHz I2C speed
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if ((now - _last_gyro_timestamp) >= raw_sample_interval_us
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&& hal.i2c->readRegisters(FLYMAPLE_GYRO_ADDRESS, FLYMAPLE_GYRO_GYROX_H, 6, buffer) == 0)
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{
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// See above re order of samples in buffer
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int16_t y = -((((int16_t)buffer[0]) << 8) | buffer[1]); // chip X axis
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int16_t x = -((((int16_t)buffer[2]) << 8) | buffer[3]); // chip Y axis
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int16_t z = -((((int16_t)buffer[4]) << 8) | buffer[5]); // chip Z axis
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Vector3f gyro = Vector3f(x,y,z);
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// Adjust for chip scaling to get radians/sec
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gyro *= FLYMAPLE_GYRO_SCALE_R_S;
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_rotate_and_correct_gyro(_gyro_instance, gyro);
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_notify_new_gyro_raw_sample(_gyro_instance, gyro);
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}
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// give back i2c semaphore
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i2c_sem->give();
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}
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#endif // CONFIG_HAL_BOARD
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