开发环境
SDK版本：nRF5_SDK_15.0.0
芯片：nRF52832-QFAA
蓝牙iBeacon实现
iBeacon的核心就是广播，不需要进行连接，通过在广播包中插入信息然后广播出去。
广播数据包最多仅可以包含31字节数据，所以设计者必须慎重选择需要包含的数据。蓝牙SIG组织在Core Specification Supplement (CSS)文件中将这31个字节数据分成多个AD Type结构，每个AD Type都有相同的结构，分别为长度字节，类型字节以及数据域。
Beacon设备可以在一个或多个标准广播数据包中编码数据，传递信息。但是编码原理可能有所差异，即帧格式不同。目前主流的三种帧格式分别为苹果公司的iBeacon，Radius Networks公司的AltBeacon以及谷歌公司的Eddystone。
因此为了与不同的beacon设备进行交互，应用开发者在开发beacon应用时需要了解对应设备的帧格式。
iBeacon帧格式
AD Field Length 表示 advertisement data的长度，即广播包有用信息的总长度；
Type 广播类型
Company ID 厂商数据字段的数据域前2字节为公司识别码。由蓝牙SIG组织分配给各公司，指示后续数据的解码方式。在上图中，0x004C为苹果公司的ID。
0x02 指明该设备为“proximity beacon”，该值在iBeacon设备中均为0x02。
UUID指明拥有该beacon设备的机构。
Major 和 Minor 主次字段用来编码位置信息，通常主字段指明某个建筑，而次字段指明在这栋建筑中的特定位置。例如“伦敦中心商场，运动产品区”。
Tx Power 发送功率字段帮助应用进行距离估算。
有关iBeacon的详细内容可以参考Getting started with iBeacon
具体代码实现
#if (GNT_IBEACON_EN)
#define APP_BEACON_INFO_LENGTH 0x17 /**< Total length of information advertised by the Beacon. */
#define APP_ADV_DATA_LENGTH 0x15 /**< Length of manufacturer specific data in the advertisement. */
#define APP_DEVICE_TYPE 0x02 /**< 0x02 refers to Beacon. */
#define APP_MEASURED_RSSI 0xC3 /**< The Beacon's measured RSSI at 1 meter distance in dBm. */
#define APP_COMPANY_IDENTIFIER 0x0059 /**< Company identifier for Nordic Semiconductor ASA. as per www.bluetooth.org. */
#define APP_MAJOR_VALUE 0x01, 0x02 /**< Major value used to identify Beacons. */
#define APP_MINOR_VALUE 0x03, 0x04 /**< Minor value used to identify Beacons. */
#define APP_BEACON_UUID 0x01, 0x12, 0x23, 0x34, \
0x45, 0x56, 0x67, 0x78, \
0x89, 0x9a, 0xab, 0xbc, \
0xcd, 0xde, 0xef, 0xf0 /**< Proprietary UUID for Beacon. */
#define MAJ_VAL_OFFSET_IN_BEACON_INFO 18 /**< Position of the MSB of the Major Value in m_beacon_info array. */
#define UICR_ADDRESS 0x10001080 /**< Address of the UICR register used by this example. The major and minor versions to be encoded into the advertising data will be picked up from this location. */
static uint8_t m_beacon_info[APP_BEACON_INFO_LENGTH] = /**< Information advertised by the Beacon. */
{
APP_DEVICE_TYPE, // Manufacturer specific information. Specifies the device type in this
// implementation.
APP_ADV_DATA_LENGTH, // Manufacturer specific information. Specifies the length of the
// manufacturer specific data in this implementation.
APP_BEACON_UUID, // 128 bit UUID value.
APP_MAJOR_VALUE, // Major arbitrary value that can be used to distinguish between Beacons.
APP_MINOR_VALUE, // Minor arbitrary value that can be used to distinguish between Beacons.
APP_MEASURED_RSSI // Manufacturer specific information. The Beacon's measured TX power in
// this implementation.
};
#endif
/**@brief Function for initializing the Advertising functionality. */
static void advertising_init(void)
{
ret_code_t err_code;
ble_advertising_init_t init;
memset(&init, 0, sizeof(init));
// 使用iBeacon广播，由于广播包长度需要控制好，部分信息可放置到广播应答包中
#if (GNT_IBEACON_EN)
ble_advdata_manuf_data_t manuf_specific_data; //厂商自定义信息
manuf_specific_data.company_identifier = APP_COMPANY_IDENTIFIER; //厂商ID
uint16_t major_value = (uint16_t)((UICR_ADDRESS & 0xFFFF0000) >> 16);
uint16_t minor_value = (uint16_t)(UICR_ADDRESS & 0x0000FFFF);
uint8_t index = MAJ_VAL_OFFSET_IN_BEACON_INFO;
m_beacon_info[index++] = MSB_16(major_value);
m_beacon_info[index++] = LSB_16(major_value);
m_beacon_info[index++] = MSB_16(minor_value);
m_beacon_info[index++] = LSB_16(minor_value);
NRF_LOG_HEXDUMP_INFO(m_beacon_info, APP_BEACON_INFO_LENGTH);
manuf_specific_data.data.p_data = (uint8_t *) m_beacon_info;
manuf_specific_data.data.size = APP_BEACON_INFO_LENGTH;
init.advdata.p_manuf_specific_data = &manuf_specific_data;
#endif
//注意advdata长度不能超过 BLE_GAP_ADV_SET_DATA_SIZE_MAX （31）
init.advdata.name_type = BLE_ADVDATA_NO_NAME; //广播iBeacon信息，长度有限 --广播时的名称显示类型（全名）BLE_ADVDATA_FULL_NAME
// init.advdata.include_appearance = true; //是否需要图标
init.advdata.flags = BLE_GAP_ADV_FLAG_BR_EDR_NOT_SUPPORTED; //蓝牙设备普通发现模式 BLE_GAP_ADV_FLAG_BR_EDR_NOT_SUPPORTED BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE
// init.advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]); //广播UUID
// init.advdata.uuids_complete.p_uuids = m_adv_uuids;
// init.advdata.p_tx_power_level = &tx_power_level; //设置发射功率
init.srdata.name_type = BLE_ADVDATA_FULL_NAME;
init.config.ble_adv_fast_enabled = true; //快速广播使能
init.config.ble_adv_fast_interval = APP_FAST_ADV_INTERVAL; //快速广播间隔 30ms
init.config.ble_adv_fast_timeout = APP_FAST_ADV_DURATION; //默认快速广播超时 20s
init.config.ble_adv_slow_enabled = true; //慢速广播使能
init.config.ble_adv_slow_interval = APP_SLOW_ADV_INTERVAL; //慢速广播间隔 200ms
// init.config.ble_adv_slow_timeout = APP_SLOW_ADV_DURATION; //默认慢速广播超时 40s
if(nrf_gpio_pin_read(USBVIN_CHECK) == 1) //USB插入
{
gnt_led_indication_set(LED_USB_IN);
g_gnt_info.gnt_usbvin_flag = 1;
init.config.ble_adv_slow_timeout = 0;
}
else
{
gnt_led_indication_set(LED_USB_OUT);
g_gnt_info.gnt_usbvin_flag = 0;
init.config.ble_adv_slow_timeout = APP_SLOW_ADV_DURATION; //默认慢速广播超时 40s
}
init.evt_handler = on_adv_evt;
err_code = ble_advertising_init(&m_advertising, &init);
APP_ERROR_CHECK(err_code);
ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
}
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