imu_detect.hpp File Reference

Framework-agnostic detection of a classic/host built-in accel+gyro IMU. More...

#include <cstdint>
#include <initializer_list>

Go to the source code of this file.

Namespaces
namespace	m5
	Top level namespace of M5Stack.

Enumerations
enum class	m5::unit::imu::ImuKind : uint8_t {   None , MPU6050 , MPU6886 , MPU9250 ,   BMI270 , SH200Q }
	Which built-in accel/gyro chip a host carries. More...

Functions
template<class ReadReg >
ImuKind	m5::unit::imu::detectBuiltinImu (ReadReg read)
	Probe the internal bus for a built-in accel/gyro chip.

Detailed Description

Framework-agnostic detection of a classic/host built-in accel+gyro IMU.

Several M5Stack hosts carry a version-dependent accel/gyro chip that M5.getBoard() cannot distinguish: e.g. Core2 v1.1 has an MPU6886 while Core2 v1.3 has a BMI270, and ATOM Matrix switched from MPU6886 to BMI270 at v1.1 – both report the same board id. detectBuiltinImu() probes the internal bus (via an injected read callback, so src/ stays free of M5Unified / Arduino Wire – same pattern as m5::unit::bmi270::detectAddress and m5::unit::imu::detectBuiltinMag) and reports which accel/gyro chip is actually present, so the caller can construct the matching driver. The probe order mirrors M5Unified's IMU_Class::begin(): MPU family first (WHO_AM_I), then BMI270 (CHIP_ID at 0x68/0x69), then SH200Q. Note: m5::unit::imu here is distinct from the m5::imu namespace that holds the AHRS types.

Enumeration Type Documentation

ImuKind

enum class m5::unit::imu::ImuKind : uint8_t

strong

Which built-in accel/gyro chip a host carries.

Enumerator
None	No accel/gyro responded (e.g. an IMU-less M5Stack Basic)
MPU6050	InvenSense MPU6050 at 0x68 (WHO_AM_I 0x68)
MPU6886	InvenSense MPU6886 at 0x68 (WHO_AM_I 0x19)
MPU9250	InvenSense MPU9250 at 0x68 (WHO_AM_I 0x71), with an internal AK8963 mag.
BMI270	Bosch BMI270 at 0x68 or 0x69 (CHIP_ID 0x24)
SH200Q	Senodia SH200Q at 0x6C (WHO_AM_I 0x18)

Function Documentation

detectBuiltinImu()

template<class ReadReg >

ImuKind m5::unit::imu::detectBuiltinImu

(

ReadReg

read

)

Probe the internal bus for a built-in accel/gyro chip.

Template Parameters

ReadReg

Callable bool(uint8_t addr, uint8_t reg, uint8_t& out) returning true on ACK

Parameters

read	The bus read callable

Returns

The detected accel/gyro chip kind (ImuKind::None if nothing answered)

The MPU family shares WHO_AM_I register 0x75 at 0x68 (MPU6886=0x19, MPU6050=0x68, MPU9250=0x71) and is resolved first, so a BMI270 (whose 0x75 is undefined) is never mistaken for an MPU. Then the BMI270 CHIP_ID (0x24 at register 0x00) is checked at both candidate addresses 0x68 and 0x69. Finally SH200Q is checked by its WHO_AM_I (0x18 at register 0x30, address 0x6C). This is detection only: it does not initialise or reset any chip.