How to set Service UUID for central and peripheral

RE: How to set Service UUID for central and peripheral

roger.k — Tue, 28 Feb 2017 01:28:20 GMT

Thank you so much for your help. It's very helpful. I solved it with your answer.

RE: How to set Service UUID for central and peripheral

Jørgen Holmefjord — Mon, 27 Feb 2017 12:17:49 GMT

If you add multiple BASE_UUIDs to the stack using sd_ble_uuid_vs_add(), you have to set the UUID type to the correct number.

In ble_app_uart example, the UUID type is set to BLE_UUID_TYPE_VENDOR_BEGIN, as there is only one vendor specific base UUID added to the stack. If you add multiple base UUIDs, you will have to set the UUID type in the order the base UUIDs are added to the stack:

If you have two vendor specific services that you want to advertise, defined like this:

#define NUS_BASE_UUID					{{0x9E, 0xCA, 0xDC, 0x24, 0x0E, 0xE5, 0xA9, 0xE0, 0x93, 0xF3, 0xA3, 0xB5, 0x00, 0x00, 0x40, 0x6E}}
#define LBS_UUID_BASE        			{{0x23, 0xD1, 0xBC, 0xEA, 0x5F, 0x78, 0x23, 0x15, 0xDE, 0xEF, 0x12, 0x12, 0x00, 0x00, 0x00, 0x00}}

#define BLE_UUID_NUS_SERVICE 			0x0001
#define LBS_UUID_SERVICE				0x1523

Your UUID types should be:

#define NUS_SERVICE_UUID_TYPE      		BLE_UUID_TYPE_VENDOR_BEGIN
#define LBS_SERVICE_UUID_TYPE			BLE_UUID_TYPE_VENDOR_BEGIN + 1

And you should add the base UUIDs to the stack in this order:

sd_ble_uuid_vs_add(NUS_BASE_UUID)
sd_ble_uuid_vs_add(LBS_UUID_BASE)

You can then add the two UUIDs, with different base UUIDs, to the advertising/scan response packet:

static ble_uuid_t                       m_adv_uuids[] = {{BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE},{LBS_UUID_SERVICE, LBS_SERVICE_UUID_TYPE}};

advdata.uuids_more_available.uuid_cnt = 1;
advdata.uuids_more_available.p_uuids  = &m_adv_uuids[0];

scanrsp.uuids_more_available.uuid_cnt = 1;
scanrsp.uuids_more_available.p_uuids  = &m_adv_uuids[1];

RE: How to set Service UUID for central and peripheral

roger.k — Mon, 27 Feb 2017 00:04:41 GMT

I want to use nRF51822 as Central and Peripheral as well. Please refer to my question at the top. I made init code for Central using "lbs_base_uuid" and then made init code for Peripheral using "p_base_uuid". Central function is working well, but Peripheral is not working well. I'm sure that I added all the code what you let me know. But it still advertises "lbs_base_uuid" not "p_base_uuid". When I remove Central init code, it advertises "p_base_uuid". I don't know why does it advertise central UUID? That's what i'm asking.

I need your help.

RE: How to set Service UUID for central and peripheral

Jørgen Holmefjord — Thu, 23 Feb 2017 13:37:00 GMT

You need to add the base UUID to the stack using sd_ble_uuid_vs_add(). This function is described in this answer. You then need to add the characteristics to the GATT table with the new base UUID. Why do you want to change the base UUID outside initialization?

RE: How to set Service UUID for central and peripheral

roger.k — Wed, 22 Feb 2017 23:38:49 GMT

If i want to use 2 different Base UUID, how can I change them? I want to change them whenever I want.

I need your help.

RE: How to set Service UUID for central and peripheral

Jørgen Holmefjord — Wed, 22 Feb 2017 14:39:12 GMT

The Nordic UART Service is a 128-bit vendor-specific UUID, as described in example documentation in the infocenter. The base UUID, NUS_BASE_UUID, is defined in ble_nus.c. This is added to the stack in services_init() with a call to sd_ble_uuid_vs_add(). When the UUID is added to the advertising data, the NUS_SERVICE_UUID_TYPE is used to get the base UUID from the stack.

RE: How to set Service UUID for central and peripheral

roger.k — Wed, 22 Feb 2017 08:08:54 GMT

How can it be 128bit? BLE_UUID_NUS_SERVICE is 16bit as below.

#define BLE_UUID_NUS_SERVICE 0x0001

I still need your help.

RE: How to set Service UUID for central and peripheral

Jørgen Holmefjord — Wed, 22 Feb 2017 07:57:02 GMT

The advdata struct can take 128-bit UUIDs, you just needs to specify the correct UUID type. You should use the type BLE_UUID_TYPE_VENDOR_BEGIN for 128-bit UUIDs.

This is how a 128-bit UUID is added to the scan response package in the ble_app_uart example:

#define NUS_SERVICE_UUID_TYPE           BLE_UUID_TYPE_VENDOR_BEGIN  
static ble_uuid_t                       m_adv_uuids[] = {{BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE}};

And in advertising_init():

scanrsp.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
scanrsp.uuids_complete.p_uuids  = m_adv_uuids;

RE: How to set Service UUID for central and peripheral

roger.k — Wed, 22 Feb 2017 05:17:23 GMT

Thank you very much for your reply. In "advertising_init" function, I can make custom advertising data as below.

static void advertising_init(void) { uint32_t err_code; ble_advdata_t advdata; ble_advdata_t scanrsp;

// Build advertising data struct to pass into @ref ble_advertising_init.
memset(&advdata, 0, sizeof(advdata));
advdata.name_type          = BLE_ADVDATA_NO_NAME;
advdata.include_appearance = false;
advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;
advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
advdata.uuids_complete.p_uuids  = m_adv_uuids;

...... }

In advdata structure, I can't see "Complete list of 128-bit UUIDs available". I think "advdata.uuids_complete" supports just 16-bit UUID. How can I send "Complete list of 128-bit UUIDs" in advertising data?

I need your help.

RE: How to set Service UUID for central and peripheral

Jørgen Holmefjord — Tue, 21 Feb 2017 09:01:19 GMT

Hi,

The function sd_ble_uuid_vs_add() is described in the infocenter. The UUIDs in the stack is not put into the advertising data by default, you have to add it yourself.

If you application advertise the LBS UUID and you are using one of the examples from the SDK (ble_app_blinky?), it is most likely added to the advertising data in advertising_init() function. You can have a look at the ble_app_uart example, as this shows how to advertise a custom UUID.

If you connect to your peripheral and perform a service discovery, do you see your custom service?

Best regards,

Jørgen