低功耗蓝牙4.0BLE编程-nrf51822开发(11)-蓝牙串口代码分析

代码实例：Board/pca100001/06 s110/experimental/ble_app_uart。

实现的功能是从uart口发送数据至另一个蓝牙串口，或是从蓝牙读取数据通过uart打印出数据。

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int main(void)

{

// Initialize

leds_init();

timers_init();

buttons_init();

uart_init();

ble_stack_init();

gap_params_init();

services_init();

advertising_init();

conn_params_init();

sec_params_init();

simple_uart_putstring(START_STRING);

advertising_start();

// Enter main loop

for (;;)

{

power_manage();

}

}

uart_init初始化uart的硬件。

当uart有数据时会进入uart中断处理：

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/**@brief Function for handling UART interrupts.

*

* @details This function will receive a single character from the UART and append it to a string.

* The string will be be sent over BLE when the last character received was a 'new line'

* i.e '\n' (hex 0x0D) or if the string has reached a length of @ref NUS_MAX_DATA_LENGTH.

*/

void UART0_IRQHandler(void)

{

static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];

static uint8_t index = 0;

uint32_t err_code;

/**@snippet [Handling the data received over UART] */

data_array[index] = simple_uart_get();

index++;

if ((data_array[index - 1] == '\n') || (index >= (BLE_NUS_MAX_DATA_LEN - 1)))

{

err_code = ble_nus_send_string(&m_nus, data_array, index + 1);

if (err_code != NRF_ERROR_INVALID_STATE)

{

APP_ERROR_CHECK(err_code);

}

index = 0;

}

/**@snippet [Handling the data received over UART] */

}

data_array是数据缓冲区，当一个接收到换行符时认为是输入结束，或是达到缓冲区的最大字节数。

ble_nus_send_string函数即是把uart输入的数据通过蓝牙发送。

此实例中建立了一个服务：

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/**@brief Function for initializing services that will be used by the application.

*/

static void services_init(void)

{

uint32_t err_code;

ble_nus_init_t nus_init;

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

nus_init.data_handler = nus_data_handler;

err_code = ble_nus_init(&m_nus, &nus_init);

APP_ERROR_CHECK(err_code);

}

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uint32_t ble_nus_init(ble_nus_t * p_nus, const ble_nus_init_t * p_nus_init)

{

uint32_t err_code;

ble_uuid_t ble_uuid;

ble_uuid128_t nus_base_uuid = {0x9E, 0xCA, 0xDC, 0x24, 0x0E, 0xE5, 0xA9, 0xE0,

0x93, 0xF3, 0xA3, 0xB5, 0x00, 0x00, 0x40, 0x6E};

if ((p_nus == NULL) || (p_nus_init == NULL))

{

return NRF_ERROR_NULL;

}

// Initialize service structure.

p_nus->conn_handle = BLE_CONN_HANDLE_INVALID;

p_nus->data_handler = p_nus_init->data_handler;

p_nus->is_notification_enabled = false;

/**@snippet [Adding proprietary Service to S110 SoftDevice] */

// Add custom base UUID.

err_code = sd_ble_uuid_vs_add(&nus_base_uuid, &p_nus->uuid_type);

if (err_code != NRF_SUCCESS)

{

return err_code;

}

ble_uuid.type = p_nus->uuid_type;

ble_uuid.uuid = BLE_UUID_NUS_SERVICE;

// Add service.

err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,

&ble_uuid,

&p_nus->service_handle);

/**@snippet [Adding proprietary Service to S110 SoftDevice] */

if (err_code != NRF_SUCCESS)

{

return err_code;

}

// Add RX Characteristic.

err_code = rx_char_add(p_nus, p_nus_init);

if (err_code != NRF_SUCCESS)

{

return err_code;

}

// Add TX Characteristic.

err_code = tx_char_add(p_nus, p_nus_init);

if (err_code != NRF_SUCCESS)

{

return err_code;

}

return NRF_SUCCESS;

}

rx_char_add()添加了接收特性，tx_char_add()添加了发送特性。

当从蓝牙接收到数据时，通过串口将数据打印出来：

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/**@brief Function for handling the @ref BLE_GATTS_EVT_WRITE event from the S110 SoftDevice.

*

* @param[in] p_dfu Nordic UART Service structure.

* @param[in] p_ble_evt Pointer to the event received from BLE stack.

*/

static void on_write(ble_nus_t * p_nus, ble_evt_t * p_ble_evt)

{

ble_gatts_evt_write_t * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;

if (

(p_evt_write->handle == p_nus->rx_handles.cccd_handle)

&&

(p_evt_write->len == 2)

)

{

if (ble_srv_is_notification_enabled(p_evt_write->data))

{

p_nus->is_notification_enabled = true;

}

else

{

p_nus->is_notification_enabled = false;

}

}

else if (

(p_evt_write->handle == p_nus->tx_handles.value_handle)

&&

(p_nus->data_handler != NULL)

)

{

p_nus->data_handler(p_nus, p_evt_write->data, p_evt_write->len);

}

else

{

// Do Nothing. This event is not relevant to this service.

}

}