Custom 128bit UUID is Advertised Incorrectly

[k3nt]

Hello, 

I am having some trouble attempting to advertise a single custom 128bit uuid. I have two custom services sharing the same base uuid. Everything works correctly after connecting, the correct uuids show up for both services and chars. The problem is that the base uuid being advertised is completely wrong, and I'm not sure why. Oddly enough the service portion seems to work, which is 0x0100 and 0x0200 in my case, if I swap the services being advertised. I followed everything in this guide to be able to advertise a full 128bit UUID in the first place https://github.com/bjornspockeli/custom_ble_service_example . I'm using nRF5 SDK V15.0.0.

My defined custom UUID base is:

// EE84xxxx-43B7-4F65-9FB9-D7B92D683E36
#define DCS_BASE_UUID {{0x36, 0x3E, 0x68, 0x2D, 0xB9, 0xD7, 0xB9, 0x9F, 0x65, 0x4F, 0xB7, 0x43, 0x00, 0x00, 0x84, 0xEE}}

static ble_uuid_t m_adv_uuids[] = {{BLE_UUID_DCS_SERVICE, BLE_UUID_TYPE_VENDOR_BEGIN}};

but this is what is showing up in the advertisement packet:

82c90100-f315-4f60-9fb8-838830daea50

Any help as to where to start to debug would be much appreciated!

-Kent

[bjorn-spockeli]

Hi Kent, 

have you verified that sd_ble_uuid_vs_add() returns NRF_SUCCESS? 

Best regards

Bjørn

[k3nt]

Hi Bjorn,

Yes, it returns 0 for both custom services.

[bjorn-spockeli]

Ok. Would you mind sharing the project folder? I would like to reproduce the issue here on a nRF52 DK. This would make it easier to debug. 

Best regards

Bjørn

[mrono]

That seems to be the Nordic base UUID (BLE_NORDIC_VENDOR_BASE_UUID), mixed with the custom service UUID.

I recall seeing this earlier. If you have two vendor specific base UUIDs, the way many Nordic examples are written don't specify which one do you want to use.

[bjorn-spockeli]

mrono: Thanks for sharing. 
 k3nt: Then there must be something with the order of the function calls that adds the VS UUID and populated the GATT table . If you have multiple vendor specific base UUIDs then you must call  sd_ble_uuid_vs_add() before any sd_ble_gatts_service_add, sd_ble_gatts_characteristic_add or sd_ble_gatts_descriptor_add calls.