About BLE server profile

BLE server profile

Steven lin
Steven.lin08@gmail.com

About BLE,BT Explanation
 BLE, it is important to understand that all the profile and

service support is entirely in the application space.
 This means that with BLE, there isn't really a need for a
serial port service to transmit custom data, since you can
easily make your custom service, that is specially tailored
for the data your application needs to transfer.

 This avoids the need for cramming all kinds of data into

serial packages, and most often this leads to much cleaner
data handling strategies and hence applications.

About BLE,BT create custom profile
 To create a custom service, you should try to follow the

general flow of the existing services, and mor or less
copy them. The battery service (ble_bas.c/ble_bas.h) is
probably the simplest one, and should provde a good
starting point.
 If you look at it, you can see that the init function first
adds a service, using the sd_ble_gatts_service_add()
function, then calls an internal function to add a
characteristic. This internal functions sets up a lot of
parameter structures, that in different ways affect the
characteristic added.

 Most services also needs to know what happens on run-

time, so you need to create a event handler to handle
events coming from the stack. This should be named
service_name_on_ble_evt(), and be called from the
applications main.c-file's ble_evt_dispatch() method.
Finally, most services also need some API function to
actually do something useful, for example the battery
service's method to update the measured battery value.

Builder custom profile
 Start ble_app_template project.

 File structure :( reference Keil C Interger develop suit)

 Client v.s Server
 Client is no have data(information).
 Client can send Request, Command and Confirmation
 Server is have data .(information,so the device usually is

server)
 Server can send Response, Notification and Indication

Nordic BLE Framework
 The Software Structure
 It have three parts: AP,GAP and GATTS.
 The SVC and ble event is the Software interrupt.

 The Software Structure
 SVC
 Event

 GAP : Advertiser , GAP Service(device ,appearance ..),

Connection and Security。

 GAP API: GAP SVC

 GAP API: GAP Event
 The GAP Events association with GATT Events.

 GAP With Center:

 GAP module:

 GATT Structure:

 GATT API:

 GATT Events:

 GATT module:

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1.main loop( have to sure the order function caller)
int main(void)
{
ble_stack_init(); //Encodes the required advertising data and passes it to the stack
bond_manager_init();//if it have .
gap_params_init();
//GAP initialization, setup all the necessary GAP,set device name
//permissions and appearance,reference appearance device
advertising_init(); //adverrising the service (profile),advertising data to stack
services_init(); //** advertising data and passes it to the stack
conn_params_init();//Connection Parameters module
sec_params_init();//security parameters
radio_notification_init();//Radio Notification event handler
// Start execution
application_timers_start();
advertising_start();
}

 Static void services_init(void)
 init function first adds a service, using the

sd_ble_gatts_service_add() function, then calls an internal
function to add a characteristic. This internal functions sets
up a lot of parameter structures, that in different ways affect
the characteristic added.
 what happens on run-time, so you need to create a event
handler to handle events coming from the stack. This should
be named service_name_on_ble_evt(), and be called from
the applications main.c-file's ble_evt_dispatch() method.
 1.caller sd_ble_gatts_service_add() then add char,last

register the event handler


https://www.bluetooth.org/en-us/specification/adopted-specifications


https://developer.bluetooth.org/gatt/services/Pages/ServiceViewer.aspx?u=or
g.bluetooth.service.battery_service.xml

 Profile , service , Characteristic ,descriptor and declare.

 Battery service :
 實作，提供value 及notify
 Service , 0x180F
 Characteristics, 0x2A19
 Descriptors(Client Characteristic Configuration), 0x2902

https://developer.bluetooth.org/gatt/descriptors/Pages/DescriptorsHomePage.aspx

 File structure:
 C:KeilARMDeviceNordicnrf51822Includebleble_servicesble_bas.h
 C:KeilARMDeviceNordicnrf51822Sourcebleble_servicesble_bas.c

 Data structure:
 Struct:
1. ble_bas_evt_t//Battery Service event
2. ble_bas_init_t//Battery Service init structure
3. ble_bas_t//Battery Service structure

 Functioin:
1. uint32_t ble_bas_init(ble_bas_t * p_bas, const ble_bas_init_t *
p_bas_init);
2. void ble_bas_on_ble_evt(ble_bas_t * p_bas, ble_evt_t * p_ble_evt);
3. uint32_t ble_bas_battery_level_update(ble_bas_t * p_bas, uint8_t
battery_level);

 /**@brief Battery Service event handler type. */
1. typedef void (*ble_bas_evt_handler_t) (ble_bas_t * p_bas,
ble_bas_evt_t * p_evt);

 /**@brief Battery Service event type. */
 typedef enum

 {

BLE_BAS_EVT_NOTIFICATION_ENABLED,
value notification enabled event. */

BLE_BAS_EVT_NOTIFICATION_DISABLED
value notification disabled event. */
 } ble_bas_evt_type_t;


/**< Battery
/**< Battery

 /**@brief Battery Service event. */
 typedef struct
 {

ble_bas_evt_type_t evt_type;
 } ble_bas_evt_t;


/**< Type of event. */

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/**@brief Battery Service init structure. This contains all options and data needed for
*
initialization of the service.*/
typedef struct
{
ble_bas_evt_handler_t
evt_handler;
/**< Event handler to be called for
handling events in the Battery Service. */
bool
support_notification;
/**< TRUE if notification of Battery
Level measurement is supported. */
ble_srv_report_ref_t *
p_report_ref;
/**< If not NULL, a Report Reference
descriptor with the specified value will be added to the Battery Level characteristic */
uint8_t
initial_batt_level;
/**< Initial battery level */
ble_srv_cccd_security_mode_t battery_level_char_attr_md; /**< Initial security level for
battery characteristics attribute */
ble_gap_conn_sec_mode_t
battery_level_report_read_perm; /**< Initial security level
for battery report read attribute */
} ble_bas_init_t;
//for pc

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/**@brief Battery Service structure. This contains various status information for the service. */
typedef struct ble_bas_s
{
ble_bas_evt_handler_t
evt_handler;
/**< Event handler to be called for
handling events in the Battery Service. */
uint16_t
service_handle;
/**< Handle of Battery Service (as
provided by the BLE stack). */
ble_gatts_char_handles_t
battery_level_handles;
/**< Handles related to the
Battery Level characteristic. */
uint16_t
report_ref_handle;
/**< Handle of the Report Reference
descriptor. */
uint8_t
battery_level_last;
/**< Last Battery Level measurement
passed to the Battery Service. */
uint16_t
conn_handle;
/**< Handle of the current connection (as
provided by the BLE stack, is BLE_CONN_HANDLE_INVALID if not in a connection). */
bool
is_notification_supported;
/**< TRUE if notification of Battery
Level is supported. */
} ble_bas_t;

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// Initialize Battery Service
memset(&bas_init, 0, sizeof(bas_init));

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// Here the sec level for the Battery Service can be changed/increased.
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&bas_init.battery_level_char_attr_md.cccd_write_perm);
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&bas_init.battery_level_char_attr_md.read_perm);
BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&bas_init.battery_level_char_attr_md.write_perm);

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BLE_GAP_CONN_SEC_MODE_SET_OPEN(&bas_init.battery_level_report_read_perm);

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bas_init.evt_handler
= NULL;
bas_init.support_notification = true;
bas_init.p_report_ref
= NULL;
bas_init.initial_batt_level = 100;

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err_code = ble_bas_init(&m_bas, &bas_init);
APP_ERROR_CHECK(err_code);

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uint32_t ble_bas_init(ble_bas_t * p_bas, const ble_bas_init_t * p_bas_init)
{
uint32_t err_code;
ble_uuid_t ble_uuid;
// Initialize service structure
p_bas->evt_handler
= p_bas_init->evt_handler;
p_bas->conn_handle
= BLE_CONN_HANDLE_INVALID;
p_bas->is_notification_supported = p_bas_init->support_notification;
p_bas->battery_level_last
= INVALID_BATTERY_LEVEL;
// Add service
BLE_UUID_BLE_ASSIGN(ble_uuid, BLE_UUID_BATTERY_SERVICE);
err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY, &ble_uuid, &p_bas->service_handle);
if (err_code != NRF_SUCCESS)
{
return err_code;
}
// Add battery level characteristic
return battery_level_char_add(p_bas, p_bas_init);
}

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/**@brief Add Battery Level characteristic.
*
* @param[in] p_bas
Battery Service structure.
* @param[in] p_bas_init Information needed to initialize the service.
*
* @return
NRF_SUCCESS on success, otherwise an error code.
*/
static uint32_t battery_level_char_add(ble_bas_t * p_bas, const ble_bas_init_t * p_bas_init)
{
uint32_t
err_code;
ble_gatts_char_md_t char_md;
ble_gatts_attr_md_t cccd_md;
ble_gatts_attr_t attr_char_value;
ble_uuid_t
ble_uuid;
ble_gatts_attr_md_t attr_md;
uint8_t
initial_battery_level;
uint8_t
encoded_report_ref[BLE_SRV_ENCODED_REPORT_REF_LEN];
uint8_t
init_len;

 以battery service 中,由上可知有一個characteristics/及

一個CCCD .而每一個characteristics由上到下:
1. ble_gatts_char_md_t char_md;//GATT Characteristic metadata
Characteristic Properties, user description descriptor, Pointer to a
presentation format structure and Attribute metadata for the
Client(server) Characteristic Configuration Descriptor.

ble_gatts_attr_md_t attr_md;//Attribute metadata

A.
A.

Read(write) permissions, Variable length, Value location and
Read(write) Authorization on every read(write) operation

ble_gatts_attr_md_t cccd_md //Attribute metadata

B.
A.

Read(write) permissions, Variable length, Value location and
Read(write) Authorization

2.

ble_gatts_attr_t

attr_char_value;//GATT Attribute

 Pointer to the attribute UUID, Pointer to the attribute metadata

structure, attribute value length in bytes and Pointer to the attribute
data if the @ref BLE_GATTS_VLOC_USER value location is
selected in the attribute metadata, this will have to point to a buffer

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/**@brief GATT Characteristic metadata. */
typedef struct
{
ble_gatt_char_props_t
char_props;
/**< Characteristic Properties. */
ble_gatt_char_ext_props_t char_ext_props;
/**< Characteristic Extended Properties. */
uint8_t*
p_char_user_desc;
/**< Pointer to a UTF-8, NULL if the descriptor is not
required. */
uint16_t
char_user_desc_max_size; /**< The maximum size in bytes of the user description
descriptor. */
uint16_t
char_user_desc_size;
/**< The size of the user description, must be smaller or
equal to char_user_desc_max_size. */
ble_gatts_char_pf_t*
p_char_pf;
/**< Pointer to a presentation format structure or NULL if
the descriptor is not required. */
ble_gatts_attr_md_t*
p_user_desc_md;
/**< Attribute metadata for the User Description
descriptor, or NULL for default values. */
p_cccd_md;
/**< Attribute metadata for the Client Characteristic
Configuration Descriptor, or NULL for default values. */
p_sccd_md;
/**< Attribute metadata for the Server Characteristic
Configuration Descriptor, or NULL for default values. */
} ble_gatts_char_md_t;

 /**@brief GATT Characteristic Properties. */
 typedef struct

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/* Standard properties */
uint8_t broadcast
:1; /**< Broadcasting of value permitted. */
uint8_t read
:1; /**< Reading value permitted. */
uint8_t write_wo_resp :1; /**< Writing value with Write Command permitted. */
uint8_t write
:1; /**< Writing value with Write Request permitted. */
uint8_t notify
:1; /**< Notications of value permitted. */
uint8_t indicate
:1; /**< Indications of value permitted. */
uint8_t auth_signed_wr :1; /**< Writing value with Signed Write Command
permitted. */
} ble_gatt_char_props_t;

 /**@brief Attribute metadata. */
 typedef struct
 {
 ble_gap_conn_sec_mode_t read_perm;
/**< Read permissions. */
 ble_gap_conn_sec_mode_t write_perm;
/**< Write permissions. */
 uint8_t
vlen
:1; /**< Variable length attribute. */
 uint8_t
vloc
:2; /**< Value location, see @ref

BLE_GATTS_VLOCS.*/
 uint8_t
rd_auth :1; /**< Read Authorization and value will
be requested from the application on every read operation. */
 uint8_t
wr_auth :1; /**< Write Authorization will be
requested from the application on every Write Request operation (but not
Write Command). */
 } ble_gatts_attr_md_t;

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/**@brief GATT Attribute. */
typedef struct
{
ble_uuid_t*
p_uuid;
/**< Pointer to the attribute UUID. */
ble_gatts_attr_md_t* p_attr_md;
/**< Pointer to the attribute metadata structure. */
uint16_t
init_len;
/**< Initial attribute value length in bytes. */
uint16_t
init_offs;
/**< Initial attribute value offset in bytes. If different from zero, the first
init_offs bytes of the attribute value will be left uninitialized. */
uint16_t
max_len;
/**< Maximum attribute value length in bytes, see @ref
BLE_GATTS_ATTR_LENS_MAX for maximum values. */
uint8_t*
p_value;
/**< Pointer to the attribute data. Please note that if the @ref
BLE_GATTS_VLOC_USER value location is selected in the attribute metadata, this will have to point to a
buffer
that remains valid through the lifetime of the attribute. This excludes usage
of automatic variables that may go out of scope or any other temporary location.
The stack may access that memory directly without the application's
knowledge. */
} ble_gatts_attr_t;

 設定

 1.cccd_md,//notify
 2. char_md
 3.BLE_UUID_BLE_ASSIGN

 4. attr_md
 5. attr_char_value
 6. sd_ble_gatts_characteristic_add

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// Add Battery Level characteristic
if (p_bas->is_notification_supported)
{
memset(&cccd_md, 0, sizeof(cccd_md));

// According to BAS_SPEC_V10, the read operation on cccd should
be possible without
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// authentication.
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BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
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cccd_md.write_perm = p_bas_init>battery_level_char_attr_md.cccd_write_perm;
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cccd_md.vloc = BLE_GATTS_VLOC_STACK;
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}

 memset(&char_md, 0, sizeof(char_md));
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char_md.char_props.read = 1;
char_md.char_props.notify = (p_bas>is_notification_supported) ? 1 : 0;
char_md.p_char_user_desc = NULL;
char_md.p_char_pf
= NULL;
char_md.p_user_desc_md = NULL;
char_md.p_cccd_md
= (p_bas>is_notification_supported) ? &cccd_md : NULL;
char_md.p_sccd_md
= NULL;

 BLE_UUID_BLE_ASSIGN(ble_uuid,

BLE_UUID_BATTERY_LEVEL_CHAR);

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memset(&attr_md, 0, sizeof(attr_md));
attr_md.read_perm = p_bas_init>battery_level_char_attr_md.read_perm;
attr_md.write_perm = p_bas_init>battery_level_char_attr_md.write_perm;
attr_md.vloc
= BLE_GATTS_VLOC_STACK;
attr_md.rd_auth = 0;
attr_md.wr_auth = 0;
attr_md.vlen
= 0;

 initial_battery_level = p_bas_init->initial_batt_level;

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memset(&attr_char_value, 0, sizeof(attr_char_value));

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attr_char_value.p_uuid
attr_char_value.p_attr_md
attr_char_value.init_len
attr_char_value.init_offs
attr_char_value.max_len
attr_char_value.p_value

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= &ble_uuid;
= &attr_md;
= sizeof(uint8_t);
= 0;
= sizeof(uint8_t);
= &initial_battery_level;

 err_code = sd_ble_gatts_characteristic_add(p_bas-

>service_handle, &char_md,
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&attr_char_value,
&p_bas>battery_level_handles);
{
return err_code;
}

if (p_bas_init->p_report_ref != NULL)
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{
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// Add Report Reference descriptor
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BLE_UUID_BLE_ASSIGN(ble_uuid, BLE_UUID_REPORT_REF_DESCR);
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memset(&attr_md, 0, sizeof(attr_md));

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attr_md.read_perm = p_bas_init->battery_level_report_read_perm;
BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&attr_md.write_perm);

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attr_md.vloc
= BLE_GATTS_VLOC_STACK;
attr_md.rd_auth = 0;
attr_md.wr_auth = 0;
attr_md.vlen
= 0;

 init_len = ble_srv_report_ref_encode(encoded_report_ref,

p_bas_init->p_report_ref);
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memset(&attr_char_value, 0, sizeof(attr_char_value));

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attr_char_value.p_uuid
attr_char_value.p_attr_md
attr_char_value.init_len
attr_char_value.init_offs
attr_char_value.max_len
attr_char_value.p_value

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= &ble_uuid;
= &attr_md;
= init_len;
= 0;
= attr_char_value.init_len;
= encoded_report_ref;

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err_code = sd_ble_gatts_descriptor_add(p_bas->battery_level_handles.value_handle,
&attr_char_value,
&p_bas->report_ref_handle);
{
return err_code;
}
}
else
{
p_bas->report_ref_handle = BLE_GATT_HANDLE_INVALID;
}

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return NRF_SUCCESS;

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}

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/**@brief Disconnect event handler.
*
* @param[in] p_bas
* @param[in] p_ble_evt Event received from the BLE
stack.
*/
static void on_disconnect(ble_bas_t * p_bas, ble_evt_t *
p_ble_evt)
{
UNUSED_PARAMETER(p_ble_evt);
p_bas->conn_handle = BLE_CONN_HANDLE_INVALID;
}

 /**@brief Connect event handler.
 *
 * @param[in] p_bas
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* @param[in] p_ble_evt Event received from the BLE
stack.
*/
static void on_connect(ble_bas_t * p_bas, ble_evt_t *
p_ble_evt)
{
p_bas->conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
}

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void ble_bas_on_ble_evt(ble_bas_t * p_bas, ble_evt_t * p_ble_evt)
{
switch (p_ble_evt->header.evt_id)
{
case BLE_GAP_EVT_CONNECTED:
on_connect(p_bas, p_ble_evt);
break;

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case BLE_GAP_EVT_DISCONNECTED:
on_disconnect(p_bas, p_ble_evt);
break;

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case BLE_GATTS_EVT_WRITE:
on_write(p_bas, p_ble_evt);
break;

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default:
break;

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}

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}

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/**@brief Write event handler.
*
* @param[in] p_bas
* @param[in] p_ble_evt Event received from the BLE stack.
*/
static void on_write(ble_bas_t * p_bas, ble_evt_t * p_ble_evt)
{
if (p_bas->is_notification_supported)
{
ble_gatts_evt_write_t * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;

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if (
(p_evt_write->handle == p_bas->battery_level_handles.cccd_handle)
&&
(p_evt_write->len == 2)
)

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{
// CCCD written, call application event handler
if (p_bas->evt_handler != NULL)
{
ble_bas_evt_t evt;

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if (ble_srv_is_notification_enabled(p_evt_write->data))
{
evt.evt_type = BLE_BAS_EVT_NOTIFICATION_ENABLED;
}
else
{
evt.evt_type = BLE_BAS_EVT_NOTIFICATION_DISABLED;
}

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p_bas->evt_handler(p_bas, &evt);

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}

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}

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}

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}

Nordic FrameWork support service
 Alert Notification Service Client,ble_ans_c

 Energon bank Service module, ble_band
 Battery Service module,ble_bas
 Blood Pressure Service module. ble_bps

 Cycling Speed and Cadence Service, ble_cscs
 Device Information Service, ble_dis
 Glucose Service module. ble_gls
 Glucose Database Service. ble_gls_db
 Human Interface Device Service, ble_hids

Nordic FrameWork support service
 Heart Rate Service ,ble_hrs

 Health Thermometer Service ,ble_hts
 Immediate Alert Service,ble_ias
 Immediate Alert Service Client,ble_ias_c

 Link Loss Service,ble_lls
 Running Speed and Cadence Service,ble_rscs
 TX Power Service,ble_tps

Reference
 Battery Service (BAS)
 http://developer.bluetooth.org/TechnologyOverview/Pages/B

AS.aspx


The external appearance of this
https://developer.bluetooth.org/gatt/characteristics/Pa
ges/CharacteristicViewer.aspx?u=org.bluetooth.characte
ristic.gap.appearance.xml

About BLE server profile

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