When you set up custom advertising data with function gecko_cmd_le_gap_bt5_set_adv_data(), you need to start advertising with discover mode "le_gap_user_data":

gecko_cmd_le_gap_start_advertising(0, le_gap_user_data, le_gap_connectable_scannable);

I think in that case you'll have to set up the primary advertising packet as well, including the Flags AdType field. For example:

uint8_t advData[] = {
  // Flags
  0x02, 0x01, 0x06,
  // Complete Local Name
  0x09, 0x09, 'B', 'R', 'D', ':', '0', '0', '0', '0'
};

gecko_cmd_le_gap_bt5_set_adv_data(0, 0, sizeof(advData), advData);

 

When you set up custom advertising data with function gecko_cmd_le_gap_bt5_set_adv_data(), you need to start advertising with discover mode "le_gap_user_data":

gecko_cmd_le_gap_start_advertising(0, le_gap_user_data, le_gap_connectable_scannable);

 

When you set up custom advertising data with function gecko_cmd_le_gap_bt5_set_adv_data(), you need to start advertising with discover mode "le_gap_user_data":

gecko_cmd_le_gap_start_advertising(0, le_gap_user_data, le_gap_connectable_scannable);

 

Actually i thought that i could use descriptors for data exchange.

I am still confused about how exactly to use descriptors since i couldn't find any of the above in my GATT profile.

Descriptors, as the name implies, are used to describe something. In BLE they describe the Characteristic in which they included. For example, you have some custom temperature characteristic in some custom service which has two byte data field. When a GATT client discovers this characteristic, all the information it gets is a 128 bit UUID and two bytes of data, which doesn't tell much about what this characteristic is and how do you interpret its data.

Now if you add Characteristic Presentation Format Descriptor to you Characteristic, it will allow you to describe the format of data field of that Characteristic. For example, you can describe your data as signed 16 bit, so the client will know that those 2 bytes are actually of type int16.

If you add Characteristic User Description Descriptor, you can describe what you characteristic does using plain text. For example, it could say "Temperature, in units of 0.01 degrees Celsius".

So, client, using information provided by these two descriptors, can by himself translate raw Characteristic data into something intelligible. Say, raw data of 0xC4, 0x11 in this example, means 45.48 degrees C.

But you don't really have to use those descriptors. If you develop both client and server devices, you can just program the format of server into a client device.

You can add descriptors either by using GATT Configurator or directly writing into a gatt.xml file. The format is described in UG118.

Actually i thought that i could use descriptors for data exchange.

I am still confused about how exactly to use descriptors since i couldn't find any of the above in my GATT profile.

Descriptors, as the name implies, are used to describe something. In BLE they describe the Characteristic in which they included. For example, you have some custom temperature characteristic in some custom service which has two byte data field. When a GATT client discovers this characteristic, all the information it gets is a 128 bit UUID and two bytes of data, which doesn't tell much about what this characteristic is and how do you interpret its data.

Now if you add Characteristic Presentation Format Descriptor to you Characteristic, it will allow you to describe the format of data field of that Characteristic. For example, you can describe your data as signed 16 bit, so the client will know that those 2 bytes are actually of type int16.

If you add Characteristic User Description Descriptor, you can describe what you characteristic does using plain text. For example, it could say "Temperature, in units of 0.01 degrees Celsius".

So, client, using information provided by these two descriptors, can by himself translate raw Characteristic data into something intelligible. Say, raw data of 0xC4, 0x11 in this example, means 45.48 degrees C.

But you don't really have to use those descriptors. If you develop both client and server devices, you can just program the format of server into a client device.

You can add descriptors either using GATT Configurator or directly writing into a gatt.xml file. The format is described in UG118.

What cellphone? Maybe it has smaller ATT_MTU and PDU sizes, so the same amount of data takes more air packets to send.

Connection interval should be greater than time length of packets you want to send + some extra space. If it only sends one packet, then maybe there's no time space left for another full packet. In other words,  It won't send another packet unless it can fully fit it, also it seems that it needs some extra time before the next connection event starts.

Connection interval should be greater than time length of packets you want to send + some extra space. If it only sends one packet, then maybe there's no time space left for another full packet. In other words,  It won't send another packet unless it can fully fit it, plus it seems that it needs some extra time before the next connection event starts.

Yes, you can add multiple descriptors to a single characteristic. For example, you can add Characteristic User Description Descriptor to add an informative text description to your characteristic (you can use <description> tag for that) and you can also have Characteristic Presentation Format Descriptor to describe the format of its data field. If I remember corectly, Client Characteristic Configuration Descriptor is added automatically to a characteristic, if you enable notifications or infications in its <properties> tag field.

These 3 are the most used ones I think. You can also define your own with a custom format.

Yes, you can add multiple descriptors to a single characteristic. For example, you can add Characteristic User Description Descriptor to add an informative text description to your characteristic (you can use <description> tag for that) and you can also have Characteristic Presentation Format to describe the format of its data field. If I remember corectly, Client Characteristic Configuration Descriptor is added automatically to a characteristic, if you enable notifications or infications in its <properties> tag field.

These 3 are the most used ones I think. You can also define your own with a custom format.