ESP32 implementation of bno08x::CommInterface using ESP-IDF I2C master driver. More...

#include <esp32_bno08x_bus.hpp>

Inheritance diagram for Esp32Bno08xI2cBus:

Collaboration diagram for Esp32Bno08xI2cBus:

Classes
struct	I2CConfig
	I2C bus and device configuration structure. More...

Public Member Functions
	Esp32Bno08xI2cBus ()
	Constructor with default configuration.

	Esp32Bno08xI2cBus (const I2CConfig &config)
	Constructor with custom I2C configuration.

	~Esp32Bno08xI2cBus ()
	Destructor - cleans up I2C resources.

BNO085Interface	GetInterfaceType () noexcept
	Identify this transport as I2C (required by CommInterface).

bool	Open () noexcept
	Open the I2C bus and initialize communication (required by CommInterface)

void	Close () noexcept
	Close the I2C bus and release resources (required by CommInterface)

int	Write (const uint8_t *data, uint32_t length) noexcept
	Write raw data to the BNO08x sensor (required by CommInterface)

int	Read (uint8_t *data, uint32_t length) noexcept
	Read raw data from the BNO08x sensor (required by CommInterface)

bool	Probe () noexcept
	Probe the I2C device to verify it's responding.

bool	DataAvailable () noexcept
	Check if new data is available (required by CommInterface)

void	Delay (uint32_t ms) noexcept
	Delay execution for specified time (required by CommInterface)

uint32_t	GetTimeUs () noexcept
	Get current time in microseconds (required by CommInterface)

void	GpioSet (bno08x::CtrlPin pin, bno08x::GpioSignal signal) noexcept
	Set a control pin to the specified signal state (required by CommInterface)

bool	Init () noexcept
	Initialize the I2C bus, GPIO, and device handle.

void	Deinit () noexcept
	Deinitialize the I2C bus and release all resources.

const I2CConfig &	getConfig () const noexcept
	Get the I2C configuration.

bool	isInitialized () const noexcept
	Check if the bus is initialized.

void	HardwareReset (uint32_t lowMs=2, uint32_t bootDelayMs=200) noexcept
	Perform hardware reset pulse on the BNO08x.

Public Member Functions inherited from bno08x::CommInterface< Esp32Bno08xI2cBus >
BNO085Interface	GetInterfaceType () noexcept
	Report the transport type this implementation provides.

bool	Open () noexcept
	Open and initialise the communication bus.

void	Close () noexcept
	Close the communication bus and release resources.

int	Write (const uint8_t *data, uint32_t length) noexcept
	Write raw bytes to the sensor.

int	Read (uint8_t *data, uint32_t length) noexcept
	Read raw bytes from the sensor.

bool	DataAvailable () noexcept
	Check whether the sensor has data ready.

void	Delay (uint32_t ms) noexcept
	Block for a specified duration.

uint32_t	GetTimeUs () noexcept
	Return the current monotonic time in microseconds.

void	GpioSet (CtrlPin pin, GpioSignal signal) noexcept
	Set a control pin to the specified signal state.

void	GpioSetActive (CtrlPin pin) noexcept
	Assert a control pin (set to ACTIVE).

void	GpioSetInactive (CtrlPin pin) noexcept
	Deassert a control pin (set to INACTIVE).

Additional Inherited Members
Protected Member Functions inherited from bno08x::CommInterface< Esp32Bno08xI2cBus >
	CommInterface ()=default
	Protected constructor – prevents direct instantiation.

	CommInterface (const CommInterface &)=delete
	Non-copyable.

	CommInterface (CommInterface &&) noexcept=default
	Movable.

	~CommInterface ()=default
	Protected destructor – prevent polymorphic deletion through base.

CommInterface &	operator= (const CommInterface &)=delete
	Non-copyable.

CommInterface &	operator= (CommInterface &&) noexcept=default
	Movable.

Detailed Description

ESP32 implementation of bno08x::CommInterface using ESP-IDF I2C master driver.

This class mirrors the proven Esp32Pca9685Bus / Esp32Pcal9555Bus implementations for consistent I2C communication behavior across HardFOC drivers. The BNO08x uses the SH-2 packet protocol over I2C (raw byte transfers, no register addressing), so the interface methods differ from the register-addressed I2cInterface, but the underlying bus management is identical.

Key improvements over the previous implementation:

Device handle caching: avoids add_device/rm_device per transaction
Header-only: consistent with other HardFOC ESP32 bus implementations
Proper resource cleanup via Init()/Deinit() pattern
Factory function for convenient instantiation

Constructor & Destructor Documentation

◆ Esp32Bno08xI2cBus() [1/2]

Esp32Bno08xI2cBus::Esp32Bno08xI2cBus ( )

inline

Constructor with default configuration.

◆ Esp32Bno08xI2cBus() [2/2]

Esp32Bno08xI2cBus::Esp32Bno08xI2cBus ( const I2CConfig & config )

inlineexplicit

Constructor with custom I2C configuration.

Parameters

config I2C bus and device configuration

◆ ~Esp32Bno08xI2cBus()

Esp32Bno08xI2cBus::~Esp32Bno08xI2cBus ( )

inline

Destructor - cleans up I2C resources.

Member Function Documentation

◆ Close()

void Esp32Bno08xI2cBus::Close ( )

inlinenoexcept

Close the I2C bus and release resources (required by CommInterface)

◆ DataAvailable()

bool Esp32Bno08xI2cBus::DataAvailable ( )

inlinenoexcept

Check if new data is available (required by CommInterface)

When an interrupt pin is configured, checks its level (active low). Without an interrupt pin, always returns true (polling mode).

Returns: true if data is available

◆ Deinit()

void Esp32Bno08xI2cBus::Deinit ( )

inlinenoexcept

Deinitialize the I2C bus and release all resources.

◆ Delay()

void Esp32Bno08xI2cBus::Delay ( uint32_t ms )

inlinenoexcept

Delay execution for specified time (required by CommInterface)

Parameters

ms	Delay duration in milliseconds

◆ getConfig()

const I2CConfig & Esp32Bno08xI2cBus::getConfig ( ) const

inlinenoexcept

Get the I2C configuration.

Returns: Reference to the I2C configuration

◆ GetInterfaceType()

BNO085Interface Esp32Bno08xI2cBus::GetInterfaceType ( )

inlinenoexcept

Identify this transport as I2C (required by CommInterface).

◆ GetTimeUs()

uint32_t Esp32Bno08xI2cBus::GetTimeUs ( )

inlinenoexcept

Get current time in microseconds (required by CommInterface)

Returns: Current monotonic time in microseconds

◆ GpioSet()

void Esp32Bno08xI2cBus::GpioSet	(	bno08x::CtrlPin	pin,
		bno08x::GpioSignal	signal )

inlinenoexcept

Set a control pin to the specified signal state (required by CommInterface)

Maps GpioSignal to physical level based on pin polarity:

RSTN: active-low (ACTIVE → GPIO 0, INACTIVE → GPIO 1)
BOOTN/WAKE/PS0/PS1: not wired in this I2C implementation (no-op)

Parameters

pin	Which control pin to drive
signal	ACTIVE to assert, INACTIVE to deassert

◆ HardwareReset()

void Esp32Bno08xI2cBus::HardwareReset	(	uint32_t	lowMs = 2,
		uint32_t	bootDelayMs = 200 )

inlinenoexcept

Perform hardware reset pulse on the BNO08x.

Asserts reset (drives RSTN low) for the specified duration, then releases it. This should be called before attempting to communicate with the device.

Parameters

lowMs	Duration to hold reset low in milliseconds (default 2ms)
bootDelayMs	Delay after releasing reset to allow sensor boot (default 200ms)

◆ Init()

bool Esp32Bno08xI2cBus::Init ( )

inlinenoexcept

Initialize the I2C bus, GPIO, and device handle.

Performs full initialization: GPIO pins, I2C master bus, and cached device handle creation. Returns true immediately on subsequent calls if already initialized.

Returns: true if successful, false otherwise

◆ isInitialized()

bool Esp32Bno08xI2cBus::isInitialized ( ) const

inlinenoexcept

Check if the bus is initialized.

Returns: true if initialized, false otherwise

◆ Open()

bool Esp32Bno08xI2cBus::Open ( )

inlinenoexcept

Open the I2C bus and initialize communication (required by CommInterface)

Initializes the I2C master bus, GPIO pins (interrupt/reset), and creates a cached device handle for the configured BNO08x address. Subsequent calls return true immediately if already initialized.

Returns: true if successful, false otherwise

◆ Probe()

bool Esp32Bno08xI2cBus::Probe ( )

inlinenoexcept

Probe the I2C device to verify it's responding.

Performs a simple I2C read to check if the device acknowledges. For BNO08x using SHTP protocol:

ACK on address = device present
Clock stretching (timeout) = device present but no data (OK)
NAK = device not present or not responding

Returns: true if device ACKs (responds), false if NAK

◆ Read()

int Esp32Bno08xI2cBus::Read	(	uint8_t *	data,
		uint32_t	length )

inlinenoexcept

Read raw data from the BNO08x sensor (required by CommInterface)

Receives raw bytes over I2C. The BNO08x SH-2 protocol does not use register addressing — all data is received as raw byte streams.

When an interrupt pin is configured, this function checks it first to avoid unnecessary I2C transactions. If the interrupt pin indicates no data is available (pin is high), it returns 0 immediately.

Note: ESP-IDF's i2c_master_receive() automatically handles clock stretching, which is required by the BNO08x datasheet (the sensor can hold SCL low when it needs more time to prepare data).

Parameters

data	Pointer to receive buffer
length	Number of bytes to read

Returns: Number of bytes read, 0 if no data, or negative on error

◆ Write()

int Esp32Bno08xI2cBus::Write	(	const uint8_t *	data,
		uint32_t	length )

inlinenoexcept

Write raw data to the BNO08x sensor (required by CommInterface)

Transmits raw bytes over I2C. The BNO08x SH-2 protocol does not use register addressing — all data is sent as raw byte streams.

Parameters

data	Pointer to data buffer
length	Number of bytes to write

Returns: Number of bytes written, or negative on error

The documentation for this class was generated from the following file:

examples/esp32/main/esp32_bno08x_bus.hpp

Classes

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Esp32Bno08xI2cBus() [1/2]

◆ Esp32Bno08xI2cBus() [2/2]

◆ ~Esp32Bno08xI2cBus()

Member Function Documentation

◆ Close()

◆ DataAvailable()

◆ Deinit()

◆ Delay()

◆ getConfig()

◆ GetInterfaceType()

◆ GetTimeUs()

◆ GpioSet()

◆ HardwareReset()

◆ Init()

◆ isInitialized()

◆ Open()

◆ Probe()

◆ Read()

◆ Write()