Difference between Limited discovery and General discovery

[beemavishnu]

Hello,

 

I am using nRF52832, SDK_15.3.0, S132 SoftDevice and Segger for flashing the image.

 

In BLE peripheral example ‘ble_app_template’, it is for doing Advertisement for some time and then go to deep sleep.

For this, flag is set to General discovery BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE with timeout of 3 minutes APP_ADV_DURATION.

Instead, why can’t we keep Limited discovery BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE with timeout of 3 minutes.

 

Ideally Limited discovery is for limited duration and General discovery for long duration. Please let me know if there are any issues if I keep Limited discovery ? Are there any dependencies on Central side. As per BLE SIG even general device discovery procedure at Center can detect Limited discover Advertisement packets.

• "Devices configured in the limited discoverable mode are discoverable for a limited period of time by other devices performing the limited or general device discovery procedure".

 

When I set flag to BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE code is getting crashed.

Thanks & Regards

Vishnu Beema

[Vidar Berg]

Hi,

APP_ADV_DURATION can be defined as 18000/BLE_GAP_ADV_TIMEOUT_LIMITED_MAX when you use BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE. Have you checked if the error occurs during adv init or adv start? 

Regards,

Vidar

[beemavishnu]

Hi,

Because of some other issue, it did not work. With BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE its working fine.

My last query on this is, is there any other dependency or any difference between "Limited discovery" and "General discover with timeout" ?

Thanks & Regards

Vishnu Beema

[Vidar Berg]

The only differences that I'm aware of are stated in the Bluetooth specification. There are no additional dependencies required for the code. Most of our BLE examples use the limited discovery flag.   

Regards,

Vidar