How to generate different UUID's for service and characteristics

RE: How to generate different UUID's for service and characteristics

Vegar Westerlund — Fri, 05 May 2017 19:28:06 GMT

Your problem is in the struct you send in to sd_ble_gatts_service_add. The call to sd_ble_uuid_vs_add will populate only the .type field of service_uuid, not .uuid. Instead, try this:

service_uuid.uuid = BLE_UUID_TEMPERATURE_SRV_UUID; // e.g. 0xaf22 or what ever...

err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
                                    &service_uuid,
                                    &m_temperature_service.service_handle);
APP_ERROR_CHECK(err_code);

You can then have BLE_UUID_TEMPERATURE_ATTR_UUID for the attribute and so on....

RE: How to generate different UUID's for service and characteristics

Jørgen Holmefjord — Fri, 24 Feb 2017 08:53:11 GMT

You say it "crashes", do you mean that you get an error code? Have you checked what the error code is using debugging? I checked your code (incorporated the relevant lines into one of the SDK examples, as I don't have your complete application), and I got two separate base UUIDs showing in nRF Connect.

RE: How to generate different UUID's for service and characteristics

Swapnil — Fri, 24 Feb 2017 08:45:59 GMT

The above code gives only one base UUID, but i need two separate base UUID's for service and characteristics. when I add separate base UUID for characteristics it get crashes. I am checking UUID's directly on mobile app nRF Connect.

RE: How to generate different UUID's for service and characteristics

Jørgen Holmefjord — Thu, 23 Feb 2017 10:29:47 GMT

It looks correct to me. How are you checking the UUIDs?

RE: How to generate different UUID's for service and characteristics

Swapnil — Wed, 22 Feb 2017 15:13:23 GMT

Thank you for your reply. This is my code: BLE stack init:

static void ble_stack_init(void)
{
	uint32_t err_code;

	nrf_clock_lf_cfg_t clock_lf_cfg = NRF_CLOCK_LFCLKSRC;

	// Initialize the SoftDevice handler module
	SOFTDEVICE_HANDLER_INIT(&clock_lf_cfg, NULL);

	ble_enable_params_t ble_enable_params;
	err_code = softdevice_enable_get_default_config(CENTRAL_LINK_COUNT,
													PERIPHERAL_LINK_COUNT,
													&ble_enable_params);
	APP_ERROR_CHECK(err_code);

	// Check the ram settings against the used number of links
	CHECK_RAM_START_ADDR(CENTRAL_LINK_COUNT, PERIPHERAL_LINK_COUNT);

	// Enable BLE stack
	ble_enable_params.gatts_enable_params.service_changed = IS_SRVC_CHANGED_CHARACT_PRESENT;
	err_code = softdevice_enable(&ble_enable_params);
	APP_ERROR_CHECK(err_code);

	// Register with the SoftDevice handler module for BLE events
	err_code = softdevice_ble_evt_handler_set(ble_evt_dispatch);
	APP_ERROR_CHECK(err_code);

	// Register with the SoftDevice handler module for BLE events
	err_code = softdevice_sys_evt_handler_set(sys_evt_dispatch);
	APP_ERROR_CHECK(err_code);

For service initialization:

void temperature_service_init()
{
    ble_uuid_t service_uuid;
    ble_uuid128_t base_uuid = BLE_UUID_TEMPERATURE_BASE_UUID;
    uint8_t i;
    uint32_t err_code;

    service_uuid.uuid = BLE_UUID_TEMPERATURE_SERVICE;
    err_code = sd_ble_uuid_vs_add(&base_uuid, &service_uuid.type);
    APP_ERROR_CHECK(err_code);

    m_temperature_service.conn_handle = BLE_CONN_HANDLE_INVALID;

    err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
                                        &service_uuid,
                                        &m_temperature_service.service_handle);
    APP_ERROR_CHECK(err_code);

    temperature_service_char_add(BLE_UUID_TEMPERATURE_CHAR_UUID, 0, true, false, true, 4);
}

temperature_service_char_add()-->

ble_uuid128_t base_uuid = {{0xa5, 0xa5, 0x00, 0x5b, 0x02, 0x00, 0x23, 0x9b, 0xe1, 0x11, 0x02, 0xd1, 0x00, 0x00, 0x34, 0x12}};
	ble_uuid_t char_uuid;
	ble_gatts_char_md_t char_md;
	ble_gatts_attr_md_t cccd_md;
	ble_gatts_attr_md_t attr_md;
	ble_gatts_attr_t attr_char_value;
	uint8_t value[20] = {0x12,0x34,0x56,0x78};
	uint32_t err_code = 0;

	char_uuid.uuid = uuid;
	char_uuid.type = BLE_UUID_TYPE_VENDOR_BEGIN;
	err_code = sd_ble_uuid_vs_add(&base_uuid, &char_uuid.type);
	APP_ERROR_CHECK(err_code);

	memset(&char_md, 0, sizeof(char_md));
	memset(&cccd_md, 0, sizeof(cccd_md));
	memset(&attr_md, 0, sizeof(attr_md));
	memset(&attr_char_value, 0, sizeof(attr_char_value));

	if(read_perm == true) {
		char_md.char_props.read = 1;
	} else {
		char_md.char_props.read = 0;
	}// if(read_perm == true)
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
	if(write_perm == true) {
		char_md.char_props.write = 1;
	} else {
		char_md.char_props.write = 0;
	}// if(write_perm == true)
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);

	cccd_md.vloc = BLE_GATTS_VLOC_STACK;
	char_md.p_cccd_md = &cccd_md;
	if(notify_status == true) {
		char_md.char_props.notify = 1;
	} else {
		char_md.char_props.notify = 0;
	}// if(notify_status == true)

	attr_md.vloc = BLE_GATTS_VLOC_STACK;

	attr_char_value.p_uuid = &char_uuid;
	attr_char_value.p_attr_md = &attr_md;
	attr_char_value.max_len = char_length;
	attr_char_value.init_len = char_length;
	attr_char_value.p_value = value;

	err_code = sd_ble_gatts_characteristic_add(m_temperature_service.service_handle,
									   &char_md,
									   &attr_char_value,
									   &m_temperature_service.char_handles[handle_num]);
	APP_ERROR_CHECK(err_code);

I want separate base UUID for service and for characteristics

RE: How to generate different UUID's for service and characteristics

Jørgen Holmefjord — Tue, 21 Feb 2017 10:01:25 GMT

Can you post some more detailed code about how you do this? How are you checking the new UUID? Also, see this thread.