AP_Compass: MMC3416 magnetometer driver

libraries/AP_Compass/AP_Compass.cpp

@@ -20,6 +20,7 @@
 #if HAL_WITH_UAVCAN
 #include "AP_Compass_UAVCAN.h"
 #endif
+#include "AP_Compass_MMC3416.h"
 #include "AP_Compass.h"
 
 extern AP_HAL::HAL& hal;

libraries/AP_Compass/AP_Compass_Backend.h

@@ -60,6 +60,7 @@ public:
         DEVTYPE_AK09916 = 0x09,
         DEVTYPE_IST8310 = 0x0A,
         DEVTYPE_ICM20948 = 0x0B,
+        DEVTYPE_MMC3416 = 0x0C,
     };
 
 

libraries/AP_Compass/AP_Compass_MMC3416.cpp

@@ -0,0 +1,172 @@
+/*
+ * 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>
+
+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
+
+AP_Compass_Backend *AP_Compass_MMC3416::probe(Compass &compass,
+                                              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(compass, std::move(dev), force_external, rotation);
+    if (!sensor || !sensor->init()) {
+        delete sensor;
+        return nullptr;
+    }
+
+    return sensor;
+}
+
+AP_Compass_MMC3416::AP_Compass_MMC3416(Compass &compass,
+                                       AP_HAL::OwnPtr<AP_HAL::Device> _dev,
+                                       bool _force_external,
+                                       enum Rotation _rotation)
+    : AP_Compass_Backend(compass)
+    , 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
+        goto fail;
+    }
+
+    dev->setup_checked_registers(2);
+
+    // reset sensor
+    dev->write_register(REG_CONTROL1, 0x80);
+    hal.scheduler->delay(10);
+    
+    dev->write_register(REG_CONTROL0, 0x0E, true); // continuous 50Hz
+    dev->write_register(REG_CONTROL1, 0x00, true); // 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 50Hz
+    dev->register_periodic_callback(20000,
+                                    FUNCTOR_BIND_MEMBER(&AP_Compass_MMC3416::timer, bool));
+
+    return true;
+
+fail:
+    dev->get_semaphore()->give();
+    return false;
+}
+
+bool AP_Compass_MMC3416::timer()
+{
+    struct PACKED {
+        uint16_t magx;
+        uint16_t magy;
+        uint16_t magz;
+    } data;
+    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;
+    Vector3f field;
+
+    if (!dev->read_registers(REG_XOUT_L, (uint8_t *)&data, sizeof(data))) {
+        goto check_registers;
+    }
+
+    // this assumes 16 bit output, which gives zero of 32768
+    field(float(data.magx) - zero_offset, float(data.magy) - zero_offset, float(data.magz) - zero_offset);
+    field *= counts_to_milliGauss;
+
+    /* rotate raw_field from sensor frame to body frame */
+    rotate_field(field, compass_instance);
+
+    /* publish raw_field (uncorrected point sample) for calibration use */
+    publish_raw_field(field, AP_HAL::micros(), compass_instance);
+
+    /* correct raw_field for known errors */
+    correct_field(field, compass_instance);
+
+    if (_sem->take(0)) {
+        accum += field;
+        accum_count++;
+        _sem->give();
+    }
+
+check_registers:
+    dev->check_next_register();
+    return true;
+}
+
+void AP_Compass_MMC3416::read()
+{
+    if (!_sem->take_nonblocking()) {
+        return;
+    }
+    if (accum_count == 0) {
+        _sem->give();
+        return;
+    }
+
+    accum /= accum_count;
+
+    publish_filtered_field(accum, compass_instance);
+
+    accum.zero();
+    accum_count = 0;
+    
+    _sem->give();
+}

libraries/AP_Compass/AP_Compass_MMC3416.h

@@ -0,0 +1,59 @@
+/*
+ * 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/>.
+ */
+#pragma once
+
+#include <AP_Common/AP_Common.h>
+#include <AP_HAL/AP_HAL.h>
+#include <AP_HAL/I2CDevice.h>
+#include <AP_Math/AP_Math.h>
+
+#include "AP_Compass.h"
+#include "AP_Compass_Backend.h"
+
+#ifndef HAL_COMPASS_MMC3416_I2C_ADDR
+# define HAL_COMPASS_MMC3416_I2C_ADDR 0x30
+#endif
+
+class AP_Compass_MMC3416 : public AP_Compass_Backend
+{
+public:
+    static AP_Compass_Backend *probe(Compass &compass,
+                                     AP_HAL::OwnPtr<AP_HAL::I2CDevice> dev,
+                                     bool force_external = false,
+                                     enum Rotation rotation = ROTATION_NONE);
+
+    void read() override;
+
+    static constexpr const char *name = "MMC3416";
+
+private:
+    AP_Compass_MMC3416(Compass &compass, AP_HAL::OwnPtr<AP_HAL::Device> dev,
+                       bool force_external,
+                       enum Rotation rotation);
+
+    AP_HAL::OwnPtr<AP_HAL::Device> dev;
+    
+    /**
+     * Device periodic callback to read data from the sensor.
+     */
+    bool init();
+    bool timer();
+
+    uint8_t compass_instance;
+    Vector3f accum;
+    uint16_t accum_count;
+    bool force_external;
+    enum Rotation rotation;
+};