[蓝牙] 6、基于nRF51822的蓝牙心率计工程消息流Log分析（详细）

 1 000001:                                          main                                                        ..main.c
 2 000002:                                   timers_init                                                        ..main.c
 3 000003:                                   gpiote_init                                                        ..main.c
 4 000004:                                  buttons_init                                                        ..main.c
 5 000005:                                ble_stack_init                                                        ..main.c
 6 000006:                             bond_manager_init                                                        ..main.c
 7 000007:                               gap_params_init                                                        ..main.c
 8 000008:                              advertising_init                                                        ..main.c
 9 000009:                                 services_init                                                        ..main.c
10 000010:                                  ble_hrs_init                 ..........Sourcelele_servicesle_hrs.c
11 000011:               heart_rate_measurement_char_add                 ..........Sourcelele_servicesle_hrs.c
12 000012:                                    hrm_encode                 ..........Sourcelele_servicesle_hrs.c
13 000013:                 body_sensor_location_char_add                 ..........Sourcelele_servicesle_hrs.c
14 000014:                                  ble_bas_init                 ..........Sourcelele_servicesle_bas.c
15 000015:                        battery_level_char_add                 ..........Sourcelele_servicesle_bas.c
16 000016:                                  ble_dis_init                 ..........Sourcelele_servicesle_dis.c
17 000017:                                      char_add                 ..........Sourcelele_servicesle_dis.c
18 000018:                              conn_params_init                                                        ..main.c
19 000019:                               sec_params_init                                                        ..main.c
20 000020:                             advertising_start                                                        ..main.c
21 000021:                                     led_start                                                         ..led.c
22 000022:                                      ppi_init                                                         ..led.c
23 000023:                                   timer1_init                                                         ..led.c
24 000024:                                   gpiote_init                                                         ..led.c

 1 uint32_t ble_hrs_init(ble_hrs_t * p_hrs, const ble_hrs_init_t * p_hrs_init)
 2 {
 3     LOG(__FUNCTION__);
 4     uint32_t   err_code;
 5     ble_uuid_t ble_uuid;
 6 
 7     // Initialize service structure
 8     p_hrs->evt_handler                 = p_hrs_init->evt_handler;
 9     p_hrs->is_sensor_contact_supported = p_hrs_init->is_sensor_contact_supported;
10     p_hrs->conn_handle                 = BLE_CONN_HANDLE_INVALID;
11     p_hrs->is_sensor_contact_detected  = false;
12     p_hrs->rr_interval_count           = 0;

这一部分主要是初始化p_hrs结构体，p_hrs_init的内容在server_init赋值的，如下：

其中第433行设置hrs的事件句柄，这样可以在其中监听hrs的相关事件，如下：
这个和ble_evt_dispatch传送BLE协议栈事件给hrs模块的ble_hrs_on_ble_evt函数稍有不同
在on_xxxx中主要处理on_connect、disconnect和write事件
注：其中case的两个事件类型是自定义的枚举型

上面437~443是设置hrs的attribute的可读可写等属性的
其中hrs_hrm_attr_md是Initial security level for heart rate service measurement attribute
其中hrs_bsl_attr_md是Initial security level for body sensor location attribute

上面89、90行的红色部分的结构体为：
可见，cccd比无cccd的多了个cccd_write_perm
这里的cccd为：客户端特性配置描述符(Client Characteristic Configuration Descriptor，CCCD)
这个带cccd的结构体在SDK描述如下：
   Security settings structure.
   This structure contains the security options needed during initialization of the service. It can be used when the charecteristics contains cccd. 
我的理解是attribute中的属性有两种：属性值或描述符。如果想支持通知或指示notify，那么就得选用cccd的这种~
注：关于BLE的一些名词[1] profileservicecharacteristicuuid关系[2]

综上：HRS服务配置了两个characteristic,他们分别是heart rate measurement characteristic（简称HRMC）和body sensor location characteristic。其中HRMC具有notify功能，不具有读写功能，即：他的值不能被其他蓝牙设备请求读写，只能主动发送给设备（称为notify，类似于web中的推送~）

14     // Add service
15     BLE_UUID_BLE_ASSIGN(ble_uuid, BLE_UUID_HEART_RATE_SERVICE);
16
17     err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY, &ble_uuid, &p_hrs->service_handle);
18     if (err_code != NRF_SUCCESS)
19     {
20         return err_code;
21     }

其中BLE_UUID_BLE_ASSIGN是一个给uuid初始赋值的宏定义：

而sd_ble_gatts_service_add负责：Add a service declaration to the local server ATT table.

谈到sd_ble_gatts_service_add，就必须谈一下Function packet format：

综上：上面14~21行代码就实现了将BLE_UUID_HEART_RATE_SERVICE加入到蓝牙协议栈中~

23     // Add heart rate measurement characteristic
24     err_code = heart_rate_measurement_char_add(p_hrs, p_hrs_init);
25     if (err_code != NRF_SUCCESS)
26     {
27         return err_code;
28     }

这里heart_rate_measurement_char_add是向上面添加的服务中添加characteristic的，非API函数，具体拆分讲解如下：
该函数前面都是一些赋值操作，最后调用了一个API函数：

如下，该API实现将一个属性声明，一个属性值声明和一个可选属性描述符声明添加进ATT表。
这个添加的属性会添加进最近添加的服务中，当然perminssions需要统一等情况要注意~
该函数的参数情况如下：
· 第一个service_handle指向该属性所在的服务
· 第二个p_char_md是属性的原数据
· 第三个p_attr_char_value是指向attribute结构体所对应的属性值
· 第四个p_handles是指向指定句柄所存储的结构体

在调用上面API之前，首先对p_char_md属性原数据进行配置attribute

接着配置p_attr_char_value进行配置：

其实经过前面的这些配置之后，再调用API函数sd_ble_gatts_characteristic_add就会形成一个下面格式的包：
注：sd_ble_gatts_characteristic_add 功能的包格式[3]

30     if (p_hrs_init->p_body_sensor_location != NULL)
31     {
32         // Add body sensor location characteristic
33         err_code = body_sensor_location_char_add(p_hrs, p_hrs_init);
34         if (err_code != NRF_SUCCESS)
35         {
36             return err_code;
37         }
38     }

最后判断是否要把body sensor location characteristic加入到hrs服务中~

40     return NRF_SUCCESS;
41 }

 1 000025:                              ble_evt_dispatch                                                        ..main.c
 2 000026:                            ble_hrs_on_ble_evt                 ..........Sourcelele_servicesle_hrs.c
 3 000027:                                    on_connect                 ..........Sourcelele_servicesle_hrs.c
 4 000028:                            ble_bas_on_ble_evt                 ..........Sourcelele_servicesle_bas.c
 5 000029:                                    on_connect                 ..........Sourcelele_servicesle_bas.c
 6 000030:                                    on_ble_evt                                                        ..main.c
 7 000031:                                      led_stop                                                         ..led.c
 8 000032:                      application_timers_start                                                        ..main.c
 9 000033:               heart_rate_meas_timeout_handler                                                        ..main.c
10 000034:           ble_hrs_heart_rate_measurement_send                 ..........Sourcelele_servicesle_hrs.c
11 000035:                                    hrm_encode                 ..........Sourcelele_servicesle_hrs.c
12 000036:               heart_rate_meas_timeout_handler                                                        ..main.c
13 000037:           ble_hrs_heart_rate_measurement_send                 ..........Sourcelele_servicesle_hrs.c
14 000038:                                    hrm_encode                 ..........Sourcelele_servicesle_hrs.c
15 000039:            battery_level_meas_timeout_handler                                                        ..main.c
16 000040:                                 battery_start                                                     ..attery.c
17 000041:                                ADC_IRQHandler                                                     ..attery.c
18 000042:                  ble_bas_battery_level_update                 ..........Sourcelele_servicesle_bas.c
19 000043:               heart_rate_meas_timeout_handler                                                        ..main.c
20 000044:           ble_hrs_heart_rate_measurement_send                 ..........Sourcelele_servicesle_hrs.c
21 000045:                                    hrm_encode                 ..........Sourcelele_servicesle_hrs.c
22 000046:               heart_rate_meas_timeout_handler                                                        ..main.c
23 000047:           ble_hrs_heart_rate_measurement_send                 ..........Sourcelele_servicesle_hrs.c
the same...

 1 /**@brief Function for dispatching a BLE stack event to all modules with a BLE stack event handler.
 2  *
 3  * @details This function is called from the BLE Stack event interrupt handler after a BLE stack
 4  *          event has been received.
 5  *
 6  * @param[in]   p_ble_evt   Bluetooth stack event.
 7  */
 8 static void ble_evt_dispatch(ble_evt_t * p_ble_evt)
 9 {
10     LOG(__FUNCTION__);
11     ble_bondmngr_on_ble_evt(p_ble_evt);
12     ble_hrs_on_ble_evt(&m_hrs, p_ble_evt);

先进入ble_hrs_on_ble_evt，进而解析事件执行on_connect,如下：eto

13     ble_bas_on_ble_evt(&bas, p_ble_evt);
14     ble_conn_params_on_ble_evt(p_ble_evt);
15     on_ble_evt(p_ble_evt);

在on_ble_evt中当检测到connected事件，
则关闭标志广播进行中的灯的定时器，
start在timer初始化中设置的hrs和bas定时器，也因此在Log中接着会轮流周期性触发hrs和bas的timeout句柄

16 }

1 002044:                              ble_evt_dispatch                                                        ..main.c
2 002045:                            ble_hrs_on_ble_evt                 ..........Sourcelele_servicesle_hrs.c
3 002046:                                      on_write                 ..........Sourcelele_servicesle_hrs.c
4 002047:                             on_hrm_cccd_write                 ..........Sourcelele_servicesle_hrs.c
5 002048:                             hrs_event_handler                                                        ..main.c
6 002049:                            ble_bas_on_ble_evt                 ..........Sourcelele_servicesle_bas.c
7 002050:                                      on_write                 ..........Sourcelele_servicesle_bas.c

 1 000895:               heart_rate_meas_timeout_handler                                                        ..main.c
 2 000896:           ble_hrs_heart_rate_measurement_send                 ..........Sourcelele_servicesle_hrs.c
 3 000897:                                    hrm_encode                 ..........Sourcelele_servicesle_hrs.c
 4 000898:                              ble_evt_dispatch                                                        ..main.c
 5 000899:                            ble_hrs_on_ble_evt                 ..........Sourcelele_servicesle_hrs.c
 6 000900:                            ble_bas_on_ble_evt                 ..........Sourcelele_servicesle_bas.c
 7 000901:                                    on_ble_evt                                                        ..main.c
 8 000902:               heart_rate_meas_timeout_handler                                                        ..main.c
 9 000903:           ble_hrs_heart_rate_measurement_send                 ..........Sourcelele_servicesle_hrs.c
10 000904:                                    hrm_encode                 ..........Sourcelele_servicesle_hrs.c
11 000905:            battery_level_meas_timeout_handler                                                        ..main.c
12 000906:                                 battery_start                                                     ..attery.c
13 000907:                                ADC_IRQHandler                                                     ..attery.c
14 000908:                  ble_bas_battery_level_update                 ..........Sourcelele_servicesle_bas.c
15 000909:                              ble_evt_dispatch                                                        ..main.c
16 000910:                            ble_hrs_on_ble_evt                 ..........Sourcelele_servicesle_hrs.c
17 000911:                            ble_bas_on_ble_evt                 ..........Sourcelele_servicesle_bas.c
18 000912:                                    on_ble_evt                                                        ..main.c

1 008913:                              ble_evt_dispatch                                                        ..main.c
2 008914:                            ble_hrs_on_ble_evt                 ..........Sourcelele_servicesle_hrs.c
3 008915:                                 on_disconnect                 ..........Sourcelele_servicesle_hrs.c
4 008916:                            ble_bas_on_ble_evt                 ..........Sourcelele_servicesle_bas.c
5 008917:                                 on_disconnect                 ..........Sourcelele_servicesle_bas.c
6 008918:                                    on_ble_evt                                                        ..main.c
7 008919:                         system_off_mode_enter                                                        ..main.c

2、Operation Code = 0xA2 (162) for sd_ble_gatts_characteristic_add, see BLE_GATTS_SVCS.

3、The parameters provided as input to sd_ble_gatts_characteristic_add are encoded in the following order