Sensor-agnostic I2C read abstraction layer. More...

#include "stdint.h"
#include "stm32f4xx_hal.h"
#include "main.h"

Enumerations
enum	sensor_t { HUMIDITY_SENSOR , PRESSURE_SENSOR , LIGHT_SENSOR , TEMPERATURE_SENSOR }
	Identifies the physical quantity to be read from a sensor. More...

Functions
float	i2c_sensor_read (uint8_t device_address, sensor_t sensor_type, void *p_handle)
	Reads a single measurement from the specified I2C sensor.
uint8_t	I2C_ScanDeviceAddress (I2C_HandleTypeDef *hi2c)
	Scans the I2C bus for the first responding device.

Detailed Description

Sensor-agnostic I2C read abstraction layer.

Provides a unified interface for reading from the three supported I2C sensors (AHT20, BMP180, BH1750) through a single function call. The caller identifies the desired measurement with a sensor_t tag; the implementation casts the generic handle pointer to the correct sensor driver type and invokes the appropriate driver read function.

Also exposes a bus-scan helper that can locate the first responding device on an I2C bus — useful during bring-up and debugging.

Author: Şule Nur Demirdaş

Date: April 2026

Enumeration Type Documentation

◆ sensor_t

enum sensor_t

Identifies the physical quantity to be read from a sensor.

Passed to i2c_sensor_read() together with the matching sensor handle so that the function can dispatch to the correct driver and extract the right field from the result.

Enumerator
HUMIDITY_SENSOR	Relative humidity in % RH (AHT20).
PRESSURE_SENSOR	Atmospheric pressure in Pa (BMP180).
LIGHT_SENSOR	Illuminance in lux (BH1750).
TEMPERATURE_SENSOR	Ambient temperature in °C (AHT20).

Function Documentation

◆ I2C_ScanDeviceAddress()

uint8_t I2C_ScanDeviceAddress ( I2C_HandleTypeDef * hi2c )

Scans the I2C bus for the first responding device.

Iterates through all 128 possible 7-bit addresses and returns the first one that acknowledges HAL_I2C_IsDeviceReady(). Intended as a diagnostic helper during hardware bring-up.

Parameters

[in] hi2c Pointer to the initialised I2C peripheral handle.

Returns: 7-bit address (0x00–0x7F) of the first responding device, or 0xFF if no device is found.

◆ i2c_sensor_read()

float i2c_sensor_read	(	uint8_t	device_address,
		sensor_t	sensor_type,
		void *	p_handle )

Reads a single measurement from the specified I2C sensor.

The function triggers a sensor read via the appropriate driver, then returns the requested physical quantity as a float. On error -1.0f is returned.