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ardupilot/libraries/AP_Compass/AP_Compass_MMC3416.cpp

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/*
* This file is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This file is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
Driver by Andrew Tridgell, Nov 2016
*/
#include "AP_Compass_MMC3416.h"
#include <AP_HAL/AP_HAL.h>
#include <utility>
#include <AP_Math/AP_Math.h>
#include <stdio.h>
#include <AP_Logger/AP_Logger.h>
extern const AP_HAL::HAL &hal;
#define REG_PRODUCT_ID 0x20
#define REG_XOUT_L 0x00
#define REG_STATUS 0x06
#define REG_CONTROL0 0x07
#define REG_CONTROL1 0x08
// bits in REG_CONTROL0
#define REG_CONTROL0_REFILL 0x80
#define REG_CONTROL0_RESET 0x40
#define REG_CONTROL0_SET 0x20
#define REG_CONTROL0_NB 0x10
#define REG_CONTROL0_TM 0x01
// datasheet says 50ms min for refill
#define MIN_DELAY_SET_RESET 50
AP_Compass_Backend *AP_Compass_MMC3416::probe(AP_HAL::OwnPtr<AP_HAL::I2CDevice> dev,
bool force_external,
enum Rotation rotation)
{
if (!dev) {
return nullptr;
}
AP_Compass_MMC3416 *sensor = new AP_Compass_MMC3416(std::move(dev), force_external, rotation);
if (!sensor || !sensor->init()) {
delete sensor;
return nullptr;
}
return sensor;
}
AP_Compass_MMC3416::AP_Compass_MMC3416(AP_HAL::OwnPtr<AP_HAL::Device> _dev,
bool _force_external,
enum Rotation _rotation)
: dev(std::move(_dev))
, force_external(_force_external)
, rotation(_rotation)
{
}
bool AP_Compass_MMC3416::init()
{
if (!dev->get_semaphore()->take(0)) {
return false;
}
dev->set_retries(10);
uint8_t whoami;
if (!dev->read_registers(REG_PRODUCT_ID, &whoami, 1) ||
whoami != 0x06) {
// not a MMC3416
dev->get_semaphore()->give();
return false;
}
// reset sensor
dev->write_register(REG_CONTROL1, 0x80);
hal.scheduler->delay(10);
dev->write_register(REG_CONTROL0, 0x00); // single shot
dev->write_register(REG_CONTROL1, 0x00); // 16 bit, 7.92ms
dev->get_semaphore()->give();
/* register the compass instance in the frontend */
compass_instance = register_compass();
printf("Found a MMC3416 on 0x%x as compass %u\n", dev->get_bus_id(), compass_instance);
set_rotation(compass_instance, rotation);
if (force_external) {
set_external(compass_instance, true);
}
dev->set_device_type(DEVTYPE_MMC3416);
set_dev_id(compass_instance, dev->get_bus_id());
dev->set_retries(1);
// call timer() at 100Hz
dev->register_periodic_callback(10000,
FUNCTOR_BIND_MEMBER(&AP_Compass_MMC3416::timer, void));
// wait 250ms for the compass to make it's initial readings
hal.scheduler->delay(250);
return true;
}
void AP_Compass_MMC3416::timer()
{
const uint16_t measure_count_limit = 50;
const uint16_t zero_offset = 32768; // 16 bit mode
const uint16_t sensitivity = 2048; // counts per Gauss, 16 bit mode
const float counts_to_milliGauss = 1.0e3f / sensitivity;
uint32_t now = AP_HAL::millis();
if (now - last_sample_ms > 500) {
// seems to be stuck or on first sample, reset state machine
state = STATE_REFILL1;
last_sample_ms = now;
}
/*
we use the SET/RESET method to remove bridge offset every
measure_count_limit measurements. This involves a fairly complex
state machine, but means we are much less sensitive to
temperature changes
*/
switch (state) {
case STATE_REFILL1:
if (dev->write_register(REG_CONTROL0, REG_CONTROL0_REFILL)) {
state = STATE_REFILL1_WAIT;
refill_start_ms = AP_HAL::millis();
}
break;
case STATE_REFILL1_WAIT: {
uint8_t status;
if (AP_HAL::millis() - refill_start_ms > MIN_DELAY_SET_RESET &&
dev->read_registers(REG_STATUS, &status, 1) &&
(status & 0x02) == 0) {
if (!dev->write_register(REG_CONTROL0, REG_CONTROL0_SET) ||
!dev->write_register(REG_CONTROL0, REG_CONTROL0_TM)) { // Take Measurement
state = STATE_REFILL1;
} else {
state = STATE_MEASURE_WAIT1;
}
}
break;
}
case STATE_MEASURE_WAIT1: {
uint8_t status;
if (dev->read_registers(REG_STATUS, &status, 1) && (status & 1)) {
if (!dev->read_registers(REG_XOUT_L, (uint8_t *)&data0[0], 6)) {
state = STATE_REFILL1;
break;
}
if (!dev->write_register(REG_CONTROL0, REG_CONTROL0_REFILL)) {
state = STATE_REFILL1;
} else {
state = STATE_REFILL2_WAIT;
refill_start_ms = AP_HAL::millis();
}
}
break;
}
case STATE_REFILL2_WAIT: {
uint8_t status;
if (AP_HAL::millis() - refill_start_ms > MIN_DELAY_SET_RESET &&
dev->read_registers(REG_STATUS, &status, 1) &&
(status & 0x02) == 0) {
if (!dev->write_register(REG_CONTROL0, REG_CONTROL0_RESET) ||
!dev->write_register(REG_CONTROL0, REG_CONTROL0_TM)) { // Take Measurement
state = STATE_REFILL1;
} else {
state = STATE_MEASURE_WAIT2;
}
}
break;
}
case STATE_MEASURE_WAIT2: {
uint8_t status;
if (!dev->read_registers(REG_STATUS, &status, 1) || !(status & 1)) {
break;
}
uint16_t data1[3];
if (!dev->read_registers(REG_XOUT_L, (uint8_t *)&data1[0], 6)) {
state = STATE_REFILL1;
break;
}
Vector3f field;
/*
calculate field and offset
*/
Vector3f f1(float(data0[0]) - zero_offset,
float(data0[1]) - zero_offset,
float(data0[2]) - zero_offset);
Vector3f f2(float(data1[0]) - zero_offset,
float(data1[1]) - zero_offset,
float(data1[2]) - zero_offset);
field = (f1 - f2) * (counts_to_milliGauss / 2);
Vector3f new_offset = (f1 + f2) * (counts_to_milliGauss / 2);
if (!have_initial_offset) {
offset = new_offset;
have_initial_offset = true;
} else {
// low pass changes to the offset
offset = offset * 0.95f + new_offset * 0.05f;
}
#if 0
AP::logger().Write("MMO", "TimeUS,Nx,Ny,Nz,Ox,Oy,Oz", "Qffffff",
AP_HAL::micros64(),
(double)new_offset.x,
(double)new_offset.y,
(double)new_offset.z,
(double)offset.x,
(double)offset.y,
(double)offset.z);
printf("F(%.1f %.1f %.1f) O(%.1f %.1f %.1f)\n",
field.x, field.y, field.z,
offset.x, offset.y, offset.z);
#endif
last_sample_ms = AP_HAL::millis();
accumulate_sample(field, compass_instance);
if (!dev->write_register(REG_CONTROL0, REG_CONTROL0_TM)) {
state = STATE_REFILL1;
} else {
state = STATE_MEASURE_WAIT3;
}
break;
}
case STATE_MEASURE_WAIT3: {
uint8_t status;
if (!dev->read_registers(REG_STATUS, &status, 1) || !(status & 1)) {
break;
}
uint16_t data1[3];
if (!dev->read_registers(REG_XOUT_L, (uint8_t *)&data1[0], 6)) {
state = STATE_REFILL1;
break;
}
Vector3f field(float(data1[0]) - zero_offset,
float(data1[1]) - zero_offset,
float(data1[2]) - zero_offset);
field *= -counts_to_milliGauss;
field += offset;
last_sample_ms = AP_HAL::millis();
accumulate_sample(field, compass_instance);
// we stay in STATE_MEASURE_WAIT3 for measure_count_limit cycles
if (measure_count++ >= measure_count_limit) {
measure_count = 0;
state = STATE_REFILL1;
} else {
if (!dev->write_register(REG_CONTROL0, REG_CONTROL0_TM)) { // Take Measurement
state = STATE_REFILL1;
}
}
break;
}
}
}
void AP_Compass_MMC3416::read()
{
drain_accumulated_samples(compass_instance);
}
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