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Sensor Service

The sensor service is responsible for managing various sensors on the device, supporting two data acquisition modes: Pull (synchronous polling) and Push (asynchronous subscription).

Core Concepts​

Pull Mode (Synchronous Polling)​

The upper layer actively reads data from the sensor, with the data source being the sensor data cache (FIFO).

Push Mode (Asynchronous Subscription)​

The upper layer registers a sensor data callback function, and the service actively notifies when new data is available.

Both modes share the same data source (sensor data cache/FIFO), uniformly scheduled by the sensor service.

FIFO Capacity​

#define EOS_SENSOR_FIFO_CAPACITY    64

Sensor Data Structures​

Sensor Instance​

typedef struct {
    eos_sensor_type_t type;           // Sensor type
    eos_dev_sensor_t *device;         // Sensor device pointer
    eos_fifo_t *fifo;                 // Data FIFO
    eos_sensor_raw_data_t latest_data;// Latest data
    uint8_t subscriber_count;         // Subscriber count
    uint32_t sample_period_ms;        // Sample period
    uint32_t last_sample_time;         // Last sample time
    bool is_active;                   // Whether active
} eos_sensor_service_instance_t;

Service Initialization​

eos_result_t eos_service_sensor_init(void);

Pull Mode API​

Read Sensor Data from FIFO​

eos_result_t eos_sensor_read(eos_sensor_type_t type, eos_sensor_raw_data_t *data);

Read Latest Sensor Data​

eos_result_t eos_sensor_read_latest(eos_sensor_type_t type, eos_sensor_raw_data_t *data);

Push Mode API​

Subscribe to Sensor Data​

Register a sensor data callback function:

eos_result_t eos_sensor_subscribe(
    eos_sensor_type_t type,
    eos_sensor_data_cb_t cb,
    void *user_data,
    uint32_t min_interval_ms
);

Parameters:

  • type: Sensor type
  • cb: Callback function
  • user_data: User data passed to callback
  • min_interval_ms: Minimum callback interval in milliseconds

Unsubscribe​

eos_result_t eos_sensor_unsubscribe(
    eos_sensor_type_t type,
    eos_sensor_data_cb_t cb,
    void *user_data
);

Sample Period Management​

Set Sample Period​

eos_result_t eos_sensor_set_sample_period(eos_sensor_type_t type, uint32_t period_ms);

Get Sample Period​

uint32_t eos_sensor_get_sample_period(eos_sensor_type_t type);

Sensor Data Notification​

Called by the driver to notify that new data is available:

void eos_sensor_notify(eos_sensor_type_t type, const eos_sensor_data_t *data, uint32_t timestamp);

Sensor Data Callback​

typedef eos_event_cb_t eos_sensor_data_cb_t;