MPU6050 i2c example expanded into C/C++ library

Author: NirajPatelRobots

i2c/mpu6050_i2c/CMakeLists.txt

@@ -1,12 +1,39 @@
-add_executable(mpu6050_i2c
-        mpu6050_i2c.c
-        )
-
-# pull in common dependencies and additional i2c hardware support
-target_link_libraries(mpu6050_i2c pico_stdlib hardware_i2c)
-
-# create map/bin/hex file etc.
-pico_add_extra_outputs(mpu6050_i2c)
-
-# add url via pico_set_program_url
-example_auto_set_url(mpu6050_i2c)
+add_library(MPU6050_i2c_pico_lib mpu6050_i2c.c)
+target_include_directories(MPU6050_i2c_pico_lib PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+# pull in common dependencies and additional i2c hardware support
+target_link_libraries(MPU6050_i2c_pico_lib pico_stdlib hardware_i2c)
+
+add_library(MPU6050_i2c_pico_cpp_lib mpu6050.cpp mpu6050_i2c.c)
+target_include_directories(MPU6050_i2c_pico_cpp_lib PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_link_libraries(MPU6050_i2c_pico_cpp_lib pico_stdlib hardware_i2c)
+
+
+add_executable(mpu6050_i2c mpu6050_i2c_main.c)
+target_link_libraries(mpu6050_i2c MPU6050_i2c_pico_lib)
+
+# create map/bin/hex file etc.
+pico_add_extra_outputs(mpu6050_i2c)
+# enable usb and uart output
+pico_enable_stdio_usb(mpu6050_i2c 1)
+pico_enable_stdio_uart(mpu6050_i2c 1)
+
+# add url via pico_set_program_url
+example_auto_set_url(mpu6050_i2c)
+
+
+add_executable(mpu6050_i2c_scale_test mpu6050_scale_test.cpp)
+target_link_libraries(mpu6050_i2c_scale_test MPU6050_i2c_pico_cpp_lib)
+
+# create map/bin/hex file etc.
+pico_add_extra_outputs(mpu6050_i2c_scale_test)
+pico_enable_stdio_usb(mpu6050_i2c_scale_test 1)
+pico_enable_stdio_uart(mpu6050_i2c_scale_test 1)
+
+
+add_executable(mpu6050_i2c_irq mpu6050_i2c_irq_main.cpp)
+target_link_libraries(mpu6050_i2c_irq MPU6050_i2c_pico_cpp_lib)
+
+# create map/bin/hex file etc.
+pico_add_extra_outputs(mpu6050_i2c_irq)
+pico_enable_stdio_usb(mpu6050_i2c_irq 1)
+pico_enable_stdio_uart(mpu6050_i2c_irq 1)

i2c/mpu6050_i2c/mpu6050.cpp

@@ -0,0 +1,99 @@
+#include "mpu6050.hpp"
+#include "mpu6050_i2c.h"
+
+
+MPU6050SensorTimingParams::MPU6050SensorTimingParams(int _bandwidth, float _delay, float _sample_rate)
+    : bandwidth(_bandwidth), delay(_delay), sample_rate(_sample_rate) {}
+
+inline const MPU6050SensorTimingParams convert(mpu6050_timing_params_t *c_struct) {  // unfortunate awkwardness of wrapping a C lib
+    return MPU6050SensorTimingParams(c_struct->bandwidth, c_struct->delay, c_struct->sample_rate);
+}
+
+MPU6050TimingParams::MPU6050TimingParams(uint8_t lowpass_filter_cfg, uint8_t sample_rate_div) {
+    mpu6050_timing_params_t accel_timing_c, gyro_timing_c;
+    mpu6050_calc_timing(lowpass_filter_cfg, sample_rate_div, &accel_timing_c, &gyro_timing_c);
+    accel_timing = convert(&accel_timing_c);
+    gyro_timing = convert(&gyro_timing_c);
+}
+
+MPU6050TimingParams::MPU6050TimingParams(const MPU6050SensorTimingParams &_accel_timing,
+                                         const MPU6050SensorTimingParams &_gyro_timing)
+    : accel_timing(_accel_timing), gyro_timing(_gyro_timing) {}
+
+
+MPU6050::MPU6050(float *accel_out, float *gyro_out, uint8_t addr) :
+ chip_temp(temp), accel(accel_out),  gyro(gyro_out), accel_scale(Scale_0), gyro_scale(Scale_0), bus_addr(addr) {
+    setup_MPU6050_i2c();
+}
+
+void MPU6050::power(uint8_t CLKSEL, bool temp_disable, bool sleep, bool cycle) {
+    mpu6050_setbusaddr(bus_addr);
+    mpu6050_power(CLKSEL, temp_disable, sleep, cycle);
+}
+
+void MPU6050::reset(void) {
+    mpu6050_setbusaddr(bus_addr);
+    mpu6050_reset();
+}
+
+void MPU6050::setscale_accel(MPU6050::Scale scale) {
+    mpu6050_setbusaddr(bus_addr);
+    mpu6050_setscale_accel((MPU6050_Scale)scale);
+    accel_scale = scale;
+}
+
+void MPU6050::setscale_gyro(MPU6050::Scale scale) {
+    mpu6050_setbusaddr(bus_addr);
+    mpu6050_setscale_gyro((MPU6050_Scale)scale);
+    gyro_scale = scale;
+}
+
+void MPU6050::read(void) {
+    mpu6050_setbusaddr(bus_addr);
+    mpu6050_read(accel, gyro, &temp, (MPU6050_Scale)accel_scale, (MPU6050_Scale)gyro_scale);
+}
+
+void MPU6050::read_accel(void) {
+    mpu6050_setbusaddr(bus_addr);
+    mpu6050_read_accel(accel, (MPU6050_Scale)accel_scale);
+}
+
+void MPU6050::read_gyro(void) {
+    mpu6050_setbusaddr(bus_addr);
+    mpu6050_read_gyro_rad(gyro, (MPU6050_Scale)gyro_scale);
+}
+
+bool MPU6050::is_connected() {
+    mpu6050_setbusaddr(bus_addr);
+    return mpu6050_is_connected();
+}
+
+void MPU6050::set_timing(uint8_t lowpass_filter_cfg, uint8_t sample_rate_div) {
+    mpu6050_setbusaddr(bus_addr);
+    mpu6050_set_timing(lowpass_filter_cfg, sample_rate_div);
+}
+
+MPU6050TimingParams MPU6050::read_timing(void) {
+    mpu6050_setbusaddr(bus_addr);
+    mpu6050_timing_params_t accel_timing_c, gyro_timing_c;
+    mpu6050_read_timing(&accel_timing_c, &gyro_timing_c);
+    return MPU6050TimingParams(convert(&accel_timing_c), convert(&gyro_timing_c));
+}
+
+void MPU6050::configure_interrupt(bool active_low, bool open_drain, bool latch_pin, bool read_clear, bool enable) {
+    mpu6050_setbusaddr(bus_addr);
+    mpu6050_configure_interrupt(active_low, open_drain, latch_pin, read_clear, enable);
+}
+
+uint8_t MPU6050::read_interrupt_status() {
+    mpu6050_setbusaddr(bus_addr);
+    return mpu6050_read_interrupt_status();
+}
+
+
+float MPU6050_max_accel(MPU6050::Scale scale) {
+    return accel_scale_vals[(int)scale];
+}
+float MPU6050_max_gyro_rad(MPU6050::Scale scale) {
+    return gyro_scale_rad[(int)scale];
+}

i2c/mpu6050_i2c/mpu6050.hpp

@@ -0,0 +1,51 @@
+/* class for using an MPU6050 IMU sensor on pi pico.
+A C++ interface to the pico example C code.
+ */
+#include "stdint.h"
+
+struct MPU6050SensorTimingParams {
+    MPU6050SensorTimingParams() = default;
+    MPU6050SensorTimingParams(int _bandwidth, float _delay, float _sample_rate);
+    int bandwidth; // lowpass filter bandwidth [Hz]
+    float delay; // lowpass filter delay [ms]
+    float sample_rate; // rate of new data loading in the register [Hz]
+};
+struct MPU6050TimingParams {
+    MPU6050TimingParams(uint8_t lowpass_filter_cfg, uint8_t sample_rate_div);
+    MPU6050TimingParams(const MPU6050SensorTimingParams &_accel_timing, const MPU6050SensorTimingParams &_gyro_timing);
+    MPU6050SensorTimingParams accel_timing, gyro_timing;
+};
+
+class MPU6050 {
+public:
+    const float &chip_temp; // [C]
+
+    MPU6050(float *accel_out, float *gyro_out, uint8_t i2c_addr=0x68); // [m/s^2], [rad/s]
+
+    void power(uint8_t CLKSEL, bool temp_disable, bool sleep, bool cycle);
+    void reset(void);
+
+    enum Scale {Scale_0 = 0, Scale_1, Scale_2, Scale_3};
+    // Warning: The first call to read() after setscale() might not have the updated scaling.
+    void setscale_accel(Scale scale); //scale 0-3 is 2g, 4g, 8g, or 16g
+    void setscale_gyro(Scale scale); // scale 0-3 is 250, 500, 1000, or 2000 deg/s
+    void read(void);
+    void read_accel(void);
+    void read_gyro(void);
+    bool is_connected(void);
+    void set_timing(uint8_t lowpass_filter_cfg, uint8_t sample_rate_div);
+    MPU6050TimingParams read_timing(void);
+    void configure_interrupt(bool active_low, // Whether the INT pin is active low or active high
+                             bool open_drain, // Whether the INT pin is push-pull or open-drain
+                             bool latch_pin,  // Whether the INT pin latches or pulses for 50us
+                             bool read_clear, // Whether interrupt status bits are cleared by reading interrupt status (default) or on any read
+                             bool enable);    // Turn interrupts on or off
+    uint8_t read_interrupt_status(); // 0 = no interrupts set, 1 = data ready
+private:
+    float *accel, *gyro, temp;
+    enum Scale accel_scale, gyro_scale;
+    uint8_t bus_addr;
+};
+
+float MPU6050_max_accel(MPU6050::Scale scale);
+float MPU6050_max_gyro_rad(MPU6050::Scale scale);