RE: Characteristic's base UUID different from Service's base UUID

Hannu Hirvonen — Tue, 26 Feb 2019 17:38:26 GMT

Is this for Server side or do we need to do this "trick" also for Client side (Central) before discovering services and characteristics form Peripheral/Server ?

RE: Characteristic's base UUID different from Service's base UUID

atune — Tue, 19 Jul 2016 09:46:25 GMT

Adding UUID bases with sd_ble_uuid_vs_add return an unique uuid_type for each custom UUID and yes, it is used with sd_ble_gatts_characteristic_add, passed in p_attr_char_value. All you need to do is add a new UUID base for each of your characteristics since you're changing the base part.

So for your example the following snipped should illustrate how to do it the SD way:

ble_uuid_t uuidA = { .uuid = 0x6666 };
ble_uuid128_t uuidA_base = { 0xAA, 0xAA, 0xAA, 0xAA, 
										0xAA, 0xAA, 0x99, 0x99, 
										0x88, 0x88, 0x77, 0x77, 
										0x00, 0x00, 0x66, 0x66 };
sd_ble_uuid_vs_add(&uuidA_base, &uuidA.type);
// uuidA is now 66666666-7777-8888-9999-AAAAAAAAAAAA

ble_uuid_t uuidB = { .uuid = 0x6666 };
ble_uuid128_t uuidB_base = { 0xAB, 0xAA, 0xAA, 0xAA, 
										0xAA, 0xAA, 0x99, 0x99, 
										0x88, 0x88, 0x77, 0x77, 
										0x00, 0x00, 0x66, 0x66 };
sd_ble_uuid_vs_add(&uuidB_base, &uuidB.type);
// uuidB is now 66666666-7777-8888-9999-AAAAAAAAAAAB

...
ble_gatts_attr_t uuidA_gatts_attr;
...
ble_gatts_attr_t uuidB_gatts_attr;
...
uuidA_gatts_attr.p_uuid = &uuidA;
....
uuidB_gatts_attr.p_uuid = &uuidB;
...
sd_ble_gatts_characteristics_add(x, y, &uuidA_gatts_attr, z);
sd_ble_gatts_characteristics_add(x, y, &uuidB_gatts_attr, z);