Ardupilot2/libraries/AP_Compass/AP_Compass_HMC5843.cpp
Andrew Tridgell 664622523d Compass: added COMPASS_LEARN and COMPASS_USE parameters
these allow you to control if the compass should be used for yaw and
if it should learn its offsets. This is useful for locking in compass
offsets once they are confirmed to be good, and for learning offsets
without using them in flights.

The default is to behave the same as previously, which is
COMPASS_LEARN=1 and COMPASS_USE=1
2012-02-25 14:51:08 +11:00

300 lines
7.5 KiB
C++

// -*- tab-width: 4; Mode: C++; c-basic-offset: 3; indent-tabs-mode: t -*-
/*
AP_Compass_HMC5843.cpp - Arduino Library for HMC5843 I2C magnetometer
Code by Jordi Muñoz and Jose Julio. DIYDrones.com
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
Sensor is conected to I2C port
Sensor is initialized in Continuos mode (10Hz)
*/
// AVR LibC Includes
#include <math.h>
#include <FastSerial.h>
#if defined(ARDUINO) && ARDUINO >= 100
#include "Arduino.h"
#else
#include "WConstants.h"
#endif
#include <I2C.h>
#include "AP_Compass_HMC5843.h"
#define COMPASS_ADDRESS 0x1E
#define ConfigRegA 0x00
#define ConfigRegB 0x01
#define magGain 0x20
#define PositiveBiasConfig 0x11
#define NegativeBiasConfig 0x12
#define NormalOperation 0x10
#define ModeRegister 0x02
#define ContinuousConversion 0x00
#define SingleConversion 0x01
// ConfigRegA valid sample averaging for 5883L
#define SampleAveraging_1 0x00
#define SampleAveraging_2 0x01
#define SampleAveraging_4 0x02
#define SampleAveraging_8 0x03
// ConfigRegA valid data output rates for 5883L
#define DataOutputRate_0_75HZ 0x00
#define DataOutputRate_1_5HZ 0x01
#define DataOutputRate_3HZ 0x02
#define DataOutputRate_7_5HZ 0x03
#define DataOutputRate_15HZ 0x04
#define DataOutputRate_30HZ 0x05
#define DataOutputRate_75HZ 0x06
// read_register - read a register value
bool AP_Compass_HMC5843::read_register(uint8_t address, uint8_t *value)
{
if (I2c.read((uint8_t)COMPASS_ADDRESS, address, 1, value) != 0) {
healthy = false;
return false;
}
return true;
}
// write_register - update a register value
bool AP_Compass_HMC5843::write_register(uint8_t address, byte value)
{
if (I2c.write((uint8_t)COMPASS_ADDRESS, address, value) != 0) {
healthy = false;
return false;
}
return true;
}
/*
the 5883L has a different orientation to the 5843. This allows us to
use a single MAG_ORIENTATION for both
*/
static void rotate_for_5883L(AP_Matrix3f *_orientation_matrix)
{
_orientation_matrix->set_and_save(_orientation_matrix->get() * Matrix3f(ROTATION_YAW_90));
}
// Read Sensor data
bool AP_Compass_HMC5843::read_raw()
{
uint8_t buff[6];
if (I2c.read(COMPASS_ADDRESS, 0x03, 6, buff) != 0) {
healthy = false;
return false;
}
int16_t rx, ry, rz;
rx = (int16_t)(buff[0] << 8) | buff[1];
if (product_id == AP_COMPASS_TYPE_HMC5883L) {
rz = (int16_t)(buff[2] << 8) | buff[3];
ry = (int16_t)(buff[4] << 8) | buff[5];
} else {
ry = (int16_t)(buff[2] << 8) | buff[3];
rz = (int16_t)(buff[4] << 8) | buff[5];
}
if (rx == -4096 || ry == -4096 || rz == -4096) {
// no valid data available
return false;
}
mag_x = -rx;
mag_y = ry;
mag_z = -rz;
return true;
}
/*
re-initialise after a IO error
*/
bool AP_Compass_HMC5843::re_initialise()
{
if (! write_register(ConfigRegA, _base_config) ||
! write_register(ConfigRegB, magGain) ||
! write_register(ModeRegister, ContinuousConversion))
return false;
return true;
}
// Public Methods //////////////////////////////////////////////////////////////
bool
AP_Compass_HMC5843::init()
{
int numAttempts = 0, good_count = 0;
bool success = false;
byte calibration_gain = 0x20;
uint16_t expected_x = 715;
uint16_t expected_yz = 715;
float gain_multiple = 1.0;
// call the parent class init for common code
Compass::init();
delay(10);
// determine if we are using 5843 or 5883L
if (! write_register(ConfigRegA, SampleAveraging_8<<5 | DataOutputRate_75HZ<<2 | NormalOperation) ||
! read_register(ConfigRegA, &_base_config)) {
healthy = false;
return false;
}
if ( _base_config == (SampleAveraging_8<<5 | DataOutputRate_75HZ<<2 | NormalOperation)) {
// a 5883L supports the sample averaging config
int old_product_id = product_id;
product_id = AP_COMPASS_TYPE_HMC5883L;
calibration_gain = 0x60;
expected_x = 766;
expected_yz = 713;
gain_multiple = 660.0 / 1090; // adjustment for runtime vs calibration gain
if (old_product_id != product_id) {
/* now we know the compass type we need to rotate the
* orientation matrix that we were given
*/
rotate_for_5883L(&_orientation_matrix);
}
} else if (_base_config == (NormalOperation | DataOutputRate_75HZ<<2)) {
product_id = AP_COMPASS_TYPE_HMC5843;
} else {
// not behaving like either supported compass type
return false;
}
calibration[0] = 0;
calibration[1] = 0;
calibration[2] = 0;
while ( success == 0 && numAttempts < 20 && good_count < 5)
{
// record number of attempts at initialisation
numAttempts++;
// force positiveBias (compass should return 715 for all channels)
if (! write_register(ConfigRegA, PositiveBiasConfig))
continue; // compass not responding on the bus
delay(50);
// set gains
if (! write_register(ConfigRegB, calibration_gain) ||
! write_register(ModeRegister, SingleConversion))
continue;
// read values from the compass
delay(50);
if (!read_raw())
continue; // we didn't read valid values
delay(10);
float cal[3];
cal[0] = fabs(expected_x / (float)mag_x);
cal[1] = fabs(expected_yz / (float)mag_y);
cal[2] = fabs(expected_yz / (float)mag_z);
if (cal[0] > 0.7 && cal[0] < 1.3 &&
cal[1] > 0.7 && cal[1] < 1.3 &&
cal[2] > 0.7 && cal[2] < 1.3) {
good_count++;
calibration[0] += cal[0];
calibration[1] += cal[1];
calibration[2] += cal[2];
}
#if 0
/* useful for debugging */
Serial.print("mag_x: ");
Serial.print(mag_x);
Serial.print(" mag_y: ");
Serial.print(mag_y);
Serial.print(" mag_z: ");
Serial.println(mag_z);
Serial.print("CalX: ");
Serial.print(calibration[0]/good_count);
Serial.print(" CalY: ");
Serial.print(calibration[1]/good_count);
Serial.print(" CalZ: ");
Serial.println(calibration[2]/good_count);
#endif
}
if (good_count >= 5) {
calibration[0] = calibration[0] * gain_multiple / good_count;
calibration[1] = calibration[1] * gain_multiple / good_count;
calibration[2] = calibration[2] * gain_multiple / good_count;
success = true;
} else {
/* best guess */
calibration[0] = 1.0;
calibration[1] = 1.0;
calibration[2] = 1.0;
}
// leave test mode
if (!re_initialise()) {
return false;
}
return success;
}
// Read Sensor data
bool AP_Compass_HMC5843::read()
{
if (!healthy) {
if (millis() < _retry_time) {
return false;
}
if (!re_initialise()) {
_retry_time = millis() + 1000;
return false;
}
}
if (!read_raw()) {
// try again in 1 second, and set I2c clock speed slower
_retry_time = millis() + 1000;
I2c.setSpeed(false);
return false;
}
mag_x *= calibration[0];
mag_y *= calibration[1];
mag_z *= calibration[2];
last_update = millis(); // record time of update
// rotate and offset the magnetometer values
// XXX this could well be done in common code...
Vector3f rot_mag = _orientation_matrix.get() * Vector3f(mag_x,mag_y,mag_z);
rot_mag = rot_mag + _offset.get();
mag_x = rot_mag.x;
mag_y = rot_mag.y;
mag_z = rot_mag.z;
healthy = true;
return true;
}
// set orientation
void
AP_Compass_HMC5843::set_orientation(const Matrix3f &rotation_matrix)
{
_orientation_matrix.set_and_save(rotation_matrix);
if (product_id == AP_COMPASS_TYPE_HMC5883L) {
rotate_for_5883L(&_orientation_matrix);
}
}