How to add an event handler for service?

[jj8431]

Hi,

I'm studying the example code of "ble_app_blinky_pca10040_s132 ". 

What confused me is I couldn't find how the "led_write_handler" is added to the service. There is a line 

// Initialize LBS.
init.led_write_handler = led_write_handler;

in main.c (line 302), and it's passed to ble_lbs_init() (in ble_lbs.c), then in ble_lbs_init(), the handler pointer is set to p_lbs:

// Initialize service structure.
p_lbs->led_write_handler = p_lbs_init->led_write_handler;

(line 198),  but then I couldn't find this pointer is passed to anywhere, how does it work?

More generally, if I want to add a custom service to GATT, to my understanding I need to call several SoftDevice APIs:

1. sd_ble_uuid_vs_add() to add the UUID to the stack's UUID table.

2. sd_ble_gatts_service_add() to add service

3. sd_ble_gatts_characteristic_add() to add characteristics for this service

There is no parameter of these functions that needs a event handler pointer, then if I need a function to handle the write event to the characteristic value, what should I do? Did I missed something?

Thanks.

[Marjeris Romero]

Hi!

 

// Initialize service structure.
p_lbs->led_write_handler = p_lbs_init->led_write_handler;

Here the member called "led_write_handler" from the struct that p_lbs points to is set to the "led_write_handler" of our service init structure, and so it is added to the service. The pointer p_lbs points to m_lbs in main.c since we called:

    err_code = ble_lbs_init(&m_lbs, &init);

in line 302.

Do this answer your question?

If you want to add custom services and characteristics I recommend to first take a look at our Bluetooth Low Energy tutorials for how to add Services and Characteristics.

Best Regards,

Marjeris

[jj8431]

Thanks. I didn't found that before. That helps. It could be helpful if there's a list or guide about these articles on your main web site or other easy to find places.