nRF52832定时器

1概述

定时器能够被配置为两种模式：定时模式和计数模式,nrf52832有五个定时器，timer0--timer4 。

2常用得函数

函数功能：初始化定时器
ret_code_t nrf_drv_timer_init	(
    nrf_drv_timer_t const *const 	p_instance,  //指向定时器驱动程序实例结构体的指针
    nrf_drv_timer_config_t const * 	p_config,  //初始化结构体，如果是NULL，使用默认配置参数
    nrf_timer_event_handler_t 	timer_event_handler   //事件句柄，不能为NULL
)

函数功能：毫秒转ticks函数

函数功能：Function for converting time in milliseconds to timer ticks.
__STATIC_INLINE uint32_t nrf_drv_timer_ms_to_ticks
(
    nrf_drv_timer_t const *const 	p_instance,  //指向定时器驱动程序实例结构体的指针
    uint32_t 	time_ms   //毫秒数
)

函数功能：拓展比较模式下设置Timer通道
void nrf_drv_timer_extended_compare	(
    nrf_drv_timer_t const *const 	p_instance,  //指向定时器驱动程序实例结构体的指针
    nrf_timer_cc_channel_t 	cc_channel,  //比较通道编号
    uint32_t 	cc_value,  //比较值
    nrf_timer_short_mask_t 	timer_short_mask,  //该通道上的比较事件和Timer任务
    bool 	enable_int   //开启或关闭比较通道的中断
)

函数功能：开启定时器
void nrf_drv_timer_enable	(	nrf_drv_timer_t const *const 	p_instance	)
函数参数：[in]	p_instance	Pointer to the driver instance structure.  //指向定时器驱动程序实例结构体指针

DEMO

1 裸机下定时器

const nrf_drv_timer_t mytimer = NRF_DRV_TIMER_INSTANCE(0);  //定义驱动程序实例

void timer_led_handler(nrf_timer_event_t event_type, void* p_context)  //定时时间到回调函数
{
	switch(event_type)
	{
		case NRF_TIMER_EVENT_COMPARE0:
		   //LED翻转
			nrf_gpio_pin_toggle(LED_2);
		    break;
		default:break;
	}

}

int main(void)
{
    uint32_t time_ms = 500; //Time(in miliseconds) between consecutive compare events.
    uint32_t time_ticks;
    uint32_t err_code = NRF_SUCCESS;

    LEDS_CONFIGURE(LEDS_MASK);//配置开发板上驱动LED的管脚为输出
    LEDS_OFF(LEDS_MASK);

    //Configure TIMER_LED for generating simple light effect - leds on board will invert his state one after the other.
    err_code = nrf_drv_timer_init(&TIMER_LED, NULL, timer_led_event_handler);
    APP_ERROR_CHECK(err_code);
    //定时时间ms转为ticks
    time_ticks = nrf_drv_timer_ms_to_ticks(&TIMER_LED, time_ms);
    //设置定时时间捕获/比较通道及该通道的比较值，使能通道的比较中断
    nrf_drv_timer_extended_compare(
         &TIMER_LED, NRF_TIMER_CC_CHANNEL0, time_ticks, NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK, true);
    //启动定时器
    nrf_drv_timer_enable(&TIMER_LED);

    while(1)
    {
        __WFI();//进入睡眠，等待中断
    }
}

2 蓝牙协议栈下，定时器和PPI配合SAADC多通道采样

/***********************************************************
例程说明：
SAADC采样开发板上电位器，光敏电阻和芯片电压，并通过BLE串口透传的方式将电压发送到APP端
时间：2018/8/10
************************************************************/
#include <stdbool.h>
#include <stdint.h>
#include <string.h>

#include "nordic_common.h"
#include "nrf.h"
#include "app_error.h"
#include "ble.h"
#include "ble_hci.h"
#include "ble_srv_common.h"
#include "ble_advdata.h"
#include "ble_advertising.h"
#include "ble_conn_params.h"
#include "boards.h"
#include "softdevice_handler.h"
#include "app_timer.h"
#include "fstorage.h"
#include "fds.h"
#include "peer_manager.h"

#include "bsp.h"
#include "bsp_btn_ble.h"
#include "sensorsim.h"
#include "nrf_gpio.h"
#include "ble_hci.h"
#include "ble_advdata.h"
#include "ble_advertising.h"
#include "ble_conn_state.h"

#define NRF_LOG_MODULE_NAME "APP"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"

/******自己定义的宏或添加的头文件*****************/
#include "app_uart.h"
#include "ble_nus_demo.h"
#include "nrf_drv_saadc.h"
#include "nrf_drv_ppi.h"
#include "nrf_drv_timer.h"

#define SAMPLES_IN_BUFFER 3  //定义SAADC采样缓存数组大小

#define UART_TX_BUF_SIZE                256    //定义缓存的大小
#define UART_RX_BUF_SIZE                256
#define BLE_NUS_MAX_DATA_LEN            20

static ble_nus_t                       m_nus;
static nrf_saadc_value_t m_buffer_pool[SAMPLES_IN_BUFFER];  //定义SAADC采样缓存数组
APP_TIMER_DEF(m_adc_sampling_timer_id);  //定义指向定时器的ID
//#define ADC_SAMPLING_INTERVAL  APP_TIMER_TICKS(1000, APP_TIMER_PRESCALER)/* ADC采样应用定时器定时时间：1秒 */
nrf_ppi_channel_t my_ppi_channel;  //ppi通道号
static const nrf_drv_timer_t    m_timer = NRF_DRV_TIMER_INSTANCE(2); //定义Timer2的驱动程序实例
/************************************************/

#define IS_SRVC_CHANGED_CHARACT_PRESENT 1                                           /**< Include or not the service_changed characteristic. if not enabled, the server's database cannot be changed for the lifetime of the device*/

#if (NRF_SD_BLE_API_VERSION == 3)
#define NRF_BLE_MAX_MTU_SIZE            GATT_MTU_SIZE_DEFAULT                       /**< MTU size used in the softdevice enabling and to reply to a BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST event. */
#endif

#define APP_FEATURE_NOT_SUPPORTED       BLE_GATT_STATUS_ATTERR_APP_BEGIN + 2        /**< Reply when unsupported features are requested. */

#define CENTRAL_LINK_COUNT              0                                           /**< Number of central links used by the application. When changing this number remember to adjust the RAM settings*/
#define PERIPHERAL_LINK_COUNT           1                                           /**< Number of peripheral links used by the application. When changing this number remember to adjust the RAM settings*/

#define DEVICE_NAME                     "Nordic_Template"                           /**< Name of device. Will be included in the advertising data. */
#define MANUFACTURER_NAME               "NordicSemiconductor"                       /**< Manufacturer. Will be passed to Device Information Service. */
#define APP_ADV_INTERVAL                300                                         /**< The advertising interval (in units of 0.625 ms. This value corresponds to 187.5 ms). */
#define APP_ADV_TIMEOUT_IN_SECONDS      180                                         /**< The advertising timeout in units of seconds. */

#define APP_TIMER_PRESCALER             0                                           /**< Value of the RTC1 PRESCALER register. */
#define APP_TIMER_OP_QUEUE_SIZE         4                                           /**< Size of timer operation queues. */

#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(100, UNIT_1_25_MS)            /**< Minimum acceptable connection interval (0.1 seconds). */
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(200, UNIT_1_25_MS)            /**< Maximum acceptable connection interval (0.2 second). */
#define SLAVE_LATENCY                   0                                           /**< Slave latency. */
#define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)             /**< Connection supervisory timeout (4 seconds). */

#define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000, APP_TIMER_PRESCALER)  /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(30000, APP_TIMER_PRESCALER) /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT    3                                           /**< Number of attempts before giving up the connection parameter negotiation. */

#define SEC_PARAM_BOND                  1                                           /**< Perform bonding. */
#define SEC_PARAM_MITM                  0                                           /**< Man In The Middle protection not required. */
#define SEC_PARAM_LESC                  0                                           /**< LE Secure Connections not enabled. */
#define SEC_PARAM_KEYPRESS              0                                           /**< Keypress notifications not enabled. */
#define SEC_PARAM_IO_CAPABILITIES       BLE_GAP_IO_CAPS_NONE                        /**< No I/O capabilities. */
#define SEC_PARAM_OOB                   0                                           /**< Out Of Band data not available. */
#define SEC_PARAM_MIN_KEY_SIZE          7                                           /**< Minimum encryption key size. */
#define SEC_PARAM_MAX_KEY_SIZE          16                                          /**< Maximum encryption key size. */

#define DEAD_BEEF                       0xDEADBEEF                                  /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */

static uint16_t m_conn_handle = BLE_CONN_HANDLE_INVALID;                            /**< Handle of the current connection. */

/* YOUR_JOB: Declare all services structure your application is using
   static ble_xx_service_t                     m_xxs;
   static ble_yy_service_t                     m_yys;
 */

// YOUR_JOB: Use UUIDs for service(s) used in your application.
static ble_uuid_t m_adv_uuids[] = {{BLE_UUID_DEVICE_INFORMATION_SERVICE, BLE_UUID_TYPE_BLE}}; /**< Universally unique service identifiers. */

static void advertising_start(void);

/**@brief Callback function for asserts in the SoftDevice.
 *
 * @details This function will be called in case of an assert in the SoftDevice.
 *
 * @warning This handler is an example only and does not fit a final product. You need to analyze
 *          how your product is supposed to react in case of Assert.
 * @warning On assert from the SoftDevice, the system can only recover on reset.
 *
 * @param[in] line_num   Line number of the failing ASSERT call.
 * @param[in] file_name  File name of the failing ASSERT call.
 */
void assert_nrf_callback(uint16_t line_num, const uint8_t * p_file_name)
{
    app_error_handler(DEAD_BEEF, line_num, p_file_name);
}

/**@brief Function for handling Peer Manager events.
 *
 * @param[in] p_evt  Peer Manager event.
 */
static void pm_evt_handler(pm_evt_t const * p_evt)
{
    ret_code_t err_code;

    switch (p_evt->evt_id)
    {
        case PM_EVT_BONDED_PEER_CONNECTED:
        {
            NRF_LOG_INFO("Connected to a previously bonded device.\r\n");
        } break;

        case PM_EVT_CONN_SEC_SUCCEEDED:
        {
            NRF_LOG_INFO("Connection secured. Role: %d. conn_handle: %d, Procedure: %d\r\n",
                         ble_conn_state_role(p_evt->conn_handle),
                         p_evt->conn_handle,
                         p_evt->params.conn_sec_succeeded.procedure);
        } break;

        case PM_EVT_CONN_SEC_FAILED:
        {
            /* Often, when securing fails, it shouldn't be restarted, for security reasons.
             * Other times, it can be restarted directly.
             * Sometimes it can be restarted, but only after changing some Security Parameters.
             * Sometimes, it cannot be restarted until the link is disconnected and reconnected.
             * Sometimes it is impossible, to secure the link, or the peer device does not support it.
             * How to handle this error is highly application dependent. */
        } break;

        case PM_EVT_CONN_SEC_CONFIG_REQ:
        {
            // Reject pairing request from an already bonded peer.
            pm_conn_sec_config_t conn_sec_config = {.allow_repairing = false};
            pm_conn_sec_config_reply(p_evt->conn_handle, &conn_sec_config);
        } break;

        case PM_EVT_STORAGE_FULL:
        {
            // Run garbage collection on the flash.
            err_code = fds_gc();
            if (err_code == FDS_ERR_BUSY || err_code == FDS_ERR_NO_SPACE_IN_QUEUES)
            {
                // Retry.
            }
            else
            {
                APP_ERROR_CHECK(err_code);
            }
        } break;

        case PM_EVT_PEERS_DELETE_SUCCEEDED:
        {
            advertising_start();
        } break;

        case PM_EVT_LOCAL_DB_CACHE_APPLY_FAILED:
        {
            // The local database has likely changed, send service changed indications.
            pm_local_database_has_changed();
        } break;

        case PM_EVT_PEER_DATA_UPDATE_FAILED:
        {
            // Assert.
            APP_ERROR_CHECK(p_evt->params.peer_data_update_failed.error);
        } break;

        case PM_EVT_PEER_DELETE_FAILED:
        {
            // Assert.
            APP_ERROR_CHECK(p_evt->params.peer_delete_failed.error);
        } break;

        case PM_EVT_PEERS_DELETE_FAILED:
        {
            // Assert.
            APP_ERROR_CHECK(p_evt->params.peers_delete_failed_evt.error);
        } break;

        case PM_EVT_ERROR_UNEXPECTED:
        {
            // Assert.
            APP_ERROR_CHECK(p_evt->params.error_unexpected.error);
        } break;

        case PM_EVT_CONN_SEC_START:
        case PM_EVT_PEER_DATA_UPDATE_SUCCEEDED:
        case PM_EVT_PEER_DELETE_SUCCEEDED:
        case PM_EVT_LOCAL_DB_CACHE_APPLIED:
        case PM_EVT_SERVICE_CHANGED_IND_SENT:
        case PM_EVT_SERVICE_CHANGED_IND_CONFIRMED:
        default:
            break;
    }
}

//定时器回调函数，在回调函数中重新开始ADC采样
static void saadc_sampling_timeout_handler(void * p_context)
{
    /*
	  定时时间到后，PPI触发采样任务，因此定时器的回调函数中并不做什么处理。
	  但函数初始化要求必须添加一个回调函数。
	  */
//    UNUSED_PARAMETER(p_context);
//	  printf("saadc_sampling_timeout_handler\r\n");
		//启动一次ADC采样。
//		nrf_drv_saadc_sample();
//    printf("time out\r\n");
}
/**@brief Function for the Timer initialization.
 *
 * @details Initializes the timer module. This creates and starts application timers.
 */
static void timers_init(void)
{
    uint32_t timer_err_code;
    // Initialize timer module.
    APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_OP_QUEUE_SIZE, false);

    //创建应用定时器
//    timer_err_code=app_timer_create(&m_adc_sampling_timer_id,
//	                   APP_TIMER_MODE_REPEATED,
//	                   saadc_sampling_timeout_handler);
//	  APP_ERROR_CHECK(timer_err_code);
}

/**@brief Function for the GAP initialization.
 *
 * @details This function sets up all the necessary GAP (Generic Access Profile) parameters of the
 *          device including the device name, appearance, and the preferred connection parameters.
 */
static void gap_params_init(void)
{
    uint32_t                err_code;
    ble_gap_conn_params_t   gap_conn_params;
    ble_gap_conn_sec_mode_t sec_mode;

    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode);

    err_code = sd_ble_gap_device_name_set(&sec_mode,
                                          (const uint8_t *)DEVICE_NAME,
                                          strlen(DEVICE_NAME));
    APP_ERROR_CHECK(err_code);

    /* YOUR_JOB: Use an appearance value matching the application's use case.
       err_code = sd_ble_gap_appearance_set(BLE_APPEARANCE_);
       APP_ERROR_CHECK(err_code); */

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

    gap_conn_params.min_conn_interval = MIN_CONN_INTERVAL;
    gap_conn_params.max_conn_interval = MAX_CONN_INTERVAL;
    gap_conn_params.slave_latency     = SLAVE_LATENCY;
    gap_conn_params.conn_sup_timeout  = CONN_SUP_TIMEOUT;

    err_code = sd_ble_gap_ppcp_set(&gap_conn_params);
    APP_ERROR_CHECK(err_code);
}

/**@brief Function for handling the YYY Service events.
 * YOUR_JOB implement a service handler function depending on the event the service you are using can generate
 *
 * @details This function will be called for all YY Service events which are passed to
 *          the application.
 *
 * @param[in]   p_yy_service   YY Service structure.
 * @param[in]   p_evt          Event received from the YY Service.
 *
 *
   static void on_yys_evt(ble_yy_service_t     * p_yy_service,
                       ble_yy_service_evt_t * p_evt)
   {
    switch (p_evt->evt_type)
    {
        case BLE_YY_NAME_EVT_WRITE:
            APPL_LOG("[APPL]: charact written with value %s. \r\n", p_evt->params.char_xx.value.p_str);
            break;

        default:
            // No implementation needed.
            break;
    }
   }*/
//串口打印nus收到的数据，也就是APP端传给单片机的数据
static void nus_data_handler(ble_nus_t * p_nus, uint8_t * p_data, uint16_t length)
{
    //串口打印nus接收到的数据
	  for(uint32_t i=0;i<length;i++)
		{
		    while(app_uart_put(p_data[i]) != NRF_SUCCESS);
		}

		//串口打印回车换行符
		while(app_uart_put('\r') != NRF_SUCCESS);
		while(app_uart_put('\n') != NRF_SUCCESS);

}

/**@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; //定义一个服务初始化结构体

	  memset(&nus_init,0,sizeof(nus_init));//先清零化结构体

    nus_init.data_handler=nus_data_handler;  //结构体变量赋值，串口接收数据处理回调函数

	  //调用串口服务初始化函数，初始化服务，初始化成功后，协议栈返回的信息存放在m_nus中
	  err_code=ble_nus_init(&m_nus,&nus_init);

	  APP_ERROR_CHECK(err_code);

}

/**@brief Function for handling the Connection Parameters Module.
 *
 * @details This function will be called for all events in the Connection Parameters Module which
 *          are passed to the application.
 *          @note All this function does is to disconnect. This could have been done by simply
 *                setting the disconnect_on_fail config parameter, but instead we use the event
 *                handler mechanism to demonstrate its use.
 *
 * @param[in] p_evt  Event received from the Connection Parameters Module.
 */
static void on_conn_params_evt(ble_conn_params_evt_t * p_evt)
{
    uint32_t err_code;

    if (p_evt->evt_type == BLE_CONN_PARAMS_EVT_FAILED)
    {
        err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE);
        APP_ERROR_CHECK(err_code);
    }
}

/**@brief Function for handling a Connection Parameters error.
 *
 * @param[in] nrf_error  Error code containing information about what went wrong.
 */
static void conn_params_error_handler(uint32_t nrf_error)
{
    APP_ERROR_HANDLER(nrf_error);
}

/**@brief Function for initializing the Connection Parameters module.
 */
static void conn_params_init(void)
{
    uint32_t               err_code;
    ble_conn_params_init_t cp_init;

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

    cp_init.p_conn_params                  = NULL;
    cp_init.first_conn_params_update_delay = FIRST_CONN_PARAMS_UPDATE_DELAY;
    cp_init.next_conn_params_update_delay  = NEXT_CONN_PARAMS_UPDATE_DELAY;
    cp_init.max_conn_params_update_count   = MAX_CONN_PARAMS_UPDATE_COUNT;
    cp_init.start_on_notify_cccd_handle    = BLE_GATT_HANDLE_INVALID;
    cp_init.disconnect_on_fail             = false;
    cp_init.evt_handler                    = on_conn_params_evt;
    cp_init.error_handler                  = conn_params_error_handler;

    err_code = ble_conn_params_init(&cp_init);
    APP_ERROR_CHECK(err_code);
}

/**@brief Function for starting timers.
 */
static void application_timers_start(void)
{
    /* YOUR_JOB: Start your timers. below is an example of how to start a timer.
       uint32_t err_code;
       err_code = app_timer_start(m_app_timer_id, TIMER_INTERVAL, NULL);
       APP_ERROR_CHECK(err_code); */
//    uint32_t err_code=app_timer_start(m_adc_sampling_timer_id,
//	                                    ADC_SAMPLING_INTERVAL,
//	                                    NULL);
//	  APP_ERROR_CHECK(err_code);
}

/**@brief Function for putting the chip into sleep mode.
 *
 * @note This function will not return.
 */
static void sleep_mode_enter(void)
{
    uint32_t err_code = bsp_indication_set(BSP_INDICATE_IDLE);

    APP_ERROR_CHECK(err_code);

    // Prepare wakeup buttons.
    err_code = bsp_btn_ble_sleep_mode_prepare();
    APP_ERROR_CHECK(err_code);

    // Go to system-off mode (this function will not return; wakeup will cause a reset).
    err_code = sd_power_system_off();
    APP_ERROR_CHECK(err_code);
}

/**@brief Function for handling advertising events.
 *
 * @details This function will be called for advertising events which are passed to the application.
 *
 * @param[in] ble_adv_evt  Advertising event.
 */
static void on_adv_evt(ble_adv_evt_t ble_adv_evt)
{
    uint32_t err_code;

    switch (ble_adv_evt)
    {
        case BLE_ADV_EVT_FAST:
            NRF_LOG_INFO("Fast advertising\r\n");
            err_code = bsp_indication_set(BSP_INDICATE_ADVERTISING);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_ADV_EVT_IDLE:
            sleep_mode_enter();
            break;

        default:
            break;
    }
}

/**@brief Function for handling the Application's BLE Stack events.
 *
 * @param[in] p_ble_evt  Bluetooth stack event.
 */
static void on_ble_evt(ble_evt_t * p_ble_evt)
{
    uint32_t err_code = NRF_SUCCESS;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_DISCONNECTED:
            NRF_LOG_INFO("Disconnected.\r\n");
            err_code = bsp_indication_set(BSP_INDICATE_IDLE);
            APP_ERROR_CHECK(err_code);
            break; // BLE_GAP_EVT_DISCONNECTED

        case BLE_GAP_EVT_CONNECTED:
            NRF_LOG_INFO("Connected.\r\n");
            err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
            APP_ERROR_CHECK(err_code);
            m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
            break; // BLE_GAP_EVT_CONNECTED

        case BLE_GATTC_EVT_TIMEOUT:
            // Disconnect on GATT Client timeout event.
            NRF_LOG_DEBUG("GATT Client Timeout.\r\n");
            err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gattc_evt.conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            APP_ERROR_CHECK(err_code);
            break; // BLE_GATTC_EVT_TIMEOUT

        case BLE_GATTS_EVT_TIMEOUT:
            // Disconnect on GATT Server timeout event.
            NRF_LOG_DEBUG("GATT Server Timeout.\r\n");
            err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            APP_ERROR_CHECK(err_code);
            break; // BLE_GATTS_EVT_TIMEOUT

        case BLE_EVT_USER_MEM_REQUEST:
            err_code = sd_ble_user_mem_reply(p_ble_evt->evt.gattc_evt.conn_handle, NULL);
            APP_ERROR_CHECK(err_code);
            break; // BLE_EVT_USER_MEM_REQUEST

        case BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST:
        {
            ble_gatts_evt_rw_authorize_request_t  req;
            ble_gatts_rw_authorize_reply_params_t auth_reply;

            req = p_ble_evt->evt.gatts_evt.params.authorize_request;

            if (req.type != BLE_GATTS_AUTHORIZE_TYPE_INVALID)
            {
                if ((req.request.write.op == BLE_GATTS_OP_PREP_WRITE_REQ)     ||
                    (req.request.write.op == BLE_GATTS_OP_EXEC_WRITE_REQ_NOW) ||
                    (req.request.write.op == BLE_GATTS_OP_EXEC_WRITE_REQ_CANCEL))
                {
                    if (req.type == BLE_GATTS_AUTHORIZE_TYPE_WRITE)
                    {
                        auth_reply.type = BLE_GATTS_AUTHORIZE_TYPE_WRITE;
                    }
                    else
                    {
                        auth_reply.type = BLE_GATTS_AUTHORIZE_TYPE_READ;
                    }
                    auth_reply.params.write.gatt_status = APP_FEATURE_NOT_SUPPORTED;
                    err_code = sd_ble_gatts_rw_authorize_reply(p_ble_evt->evt.gatts_evt.conn_handle,
                                                               &auth_reply);
                    APP_ERROR_CHECK(err_code);
                }
            }
        } break; // BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST

#if (NRF_SD_BLE_API_VERSION == 3)
        case BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST:
            err_code = sd_ble_gatts_exchange_mtu_reply(p_ble_evt->evt.gatts_evt.conn_handle,
                                                       NRF_BLE_MAX_MTU_SIZE);
            APP_ERROR_CHECK(err_code);
            break; // BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST
#endif

        default:
            // No implementation needed.
            break;
    }
}

/**@brief Function for dispatching a BLE stack event to all modules with a BLE stack event handler.
 *
 * @details This function is called from the BLE Stack event interrupt handler after a BLE stack
 *          event has been received.
 *
 * @param[in] p_ble_evt  Bluetooth stack event.
 */
static void ble_evt_dispatch(ble_evt_t * p_ble_evt)
{
    /** The Connection state module has to be fed BLE events in order to function correctly
     * Remember to call ble_conn_state_on_ble_evt before calling any ble_conns_state_* functions. */
    ble_conn_state_on_ble_evt(p_ble_evt);
    pm_on_ble_evt(p_ble_evt);
    ble_conn_params_on_ble_evt(p_ble_evt);
    bsp_btn_ble_on_ble_evt(p_ble_evt);
    on_ble_evt(p_ble_evt);
    ble_advertising_on_ble_evt(p_ble_evt);
	  ble_nus_on_ble_evt(&m_nus,p_ble_evt);  //nus事件处理
    /*YOUR_JOB add calls to _on_ble_evt functions from each service your application is using
       ble_xxs_on_ble_evt(&m_xxs, p_ble_evt);
       ble_yys_on_ble_evt(&m_yys, p_ble_evt);
     */
}

/**@brief Function for dispatching a system event to interested modules.
 *
 * @details This function is called from the System event interrupt handler after a system
 *          event has been received.
 *
 * @param[in] sys_evt  System stack event.
 */
static void sys_evt_dispatch(uint32_t sys_evt)
{
    // Dispatch the system event to the fstorage module, where it will be
    // dispatched to the Flash Data Storage (FDS) module.
    fs_sys_event_handler(sys_evt);

    // Dispatch to the Advertising module last, since it will check if there are any
    // pending flash operations in fstorage. Let fstorage process system events first,
    // so that it can report correctly to the Advertising module.
    ble_advertising_on_sys_evt(sys_evt);
}

/**@brief Function for initializing the BLE stack.
 *
 * @details Initializes the SoftDevice and the BLE event interrupt.
 */
static void ble_stack_init(void)
{

    uint32_t err_code;
/*************************初始化协议栈处理模块**************************************/
    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);
/*************************使能协议栈***********************************/
    // Check the ram settings against the used number of links
    CHECK_RAM_START_ADDR(CENTRAL_LINK_COUNT, PERIPHERAL_LINK_COUNT);

    // Enable BLE stack.
#if (NRF_SD_BLE_API_VERSION == 3)
    ble_enable_params.gatt_enable_params.att_mtu = NRF_BLE_MAX_MTU_SIZE;
#endif
    err_code = softdevice_enable(&ble_enable_params);
    APP_ERROR_CHECK(err_code);
/****************************注册派发函数**************************************/
    // 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);
}

/**@brief Function for the Peer Manager initialization.
 *
 * @param[in] erase_bonds  Indicates whether bonding information should be cleared from
 *                         persistent storage during initialization of the Peer Manager.
 */
static void peer_manager_init(bool erase_bonds)
{
    ble_gap_sec_params_t sec_param;
    ret_code_t           err_code;

    err_code = pm_init();
    APP_ERROR_CHECK(err_code);

    if (erase_bonds)
    {
        err_code = pm_peers_delete();
        APP_ERROR_CHECK(err_code);
    }

    memset(&sec_param, 0, sizeof(ble_gap_sec_params_t));

    // Security parameters to be used for all security procedures.
    sec_param.bond           = SEC_PARAM_BOND;
    sec_param.mitm           = SEC_PARAM_MITM;
    sec_param.lesc           = SEC_PARAM_LESC;
    sec_param.keypress       = SEC_PARAM_KEYPRESS;
    sec_param.io_caps        = SEC_PARAM_IO_CAPABILITIES;
    sec_param.oob            = SEC_PARAM_OOB;
    sec_param.min_key_size   = SEC_PARAM_MIN_KEY_SIZE;
    sec_param.max_key_size   = SEC_PARAM_MAX_KEY_SIZE;
    sec_param.kdist_own.enc  = 1;
    sec_param.kdist_own.id   = 1;
    sec_param.kdist_peer.enc = 1;
    sec_param.kdist_peer.id  = 1;

    err_code = pm_sec_params_set(&sec_param);
    APP_ERROR_CHECK(err_code);

    err_code = pm_register(pm_evt_handler);
    APP_ERROR_CHECK(err_code);
}

/**@brief Function for handling events from the BSP module.
 *
 * @param[in]   event   Event generated when button is pressed.
 */
static void bsp_event_handler(bsp_event_t event)
{
    uint32_t err_code;
    //判断不同的事件类型,不同的事件类型执行不同的操作
    switch (event)
    {
        case BSP_EVENT_SLEEP:
            sleep_mode_enter();
            break; // BSP_EVENT_SLEEP

        case BSP_EVENT_DISCONNECT:
            err_code = sd_ble_gap_disconnect(m_conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            if (err_code != NRF_ERROR_INVALID_STATE)
            {
                APP_ERROR_CHECK(err_code);
            }
            break; // BSP_EVENT_DISCONNECT

				//移除广播白名单
        case BSP_EVENT_WHITELIST_OFF:
            if (m_conn_handle == BLE_CONN_HANDLE_INVALID)
            {
                err_code = ble_advertising_restart_without_whitelist();
                if (err_code != NRF_ERROR_INVALID_STATE)
                {
                    APP_ERROR_CHECK(err_code);
                }
            }
            break; // BSP_EVENT_KEY_0

        default:
            break;
    }
}

/**@brief Function for initializing the Advertising functionality.
 */
static void advertising_init(void)
{
    uint32_t               err_code;
    ble_advdata_t          advdata;
    ble_adv_modes_config_t options;

    // Build advertising data struct to pass into @ref ble_advertising_init.
    memset(&advdata, 0, sizeof(advdata));

    advdata.name_type               = BLE_ADVDATA_FULL_NAME;
    advdata.include_appearance      = true;
    advdata.flags                   = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;
    advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    advdata.uuids_complete.p_uuids  = m_adv_uuids;

    memset(&options, 0, sizeof(options));
    options.ble_adv_fast_enabled  = true;
    options.ble_adv_fast_interval = APP_ADV_INTERVAL;
    options.ble_adv_fast_timeout  = APP_ADV_TIMEOUT_IN_SECONDS;

    err_code = ble_advertising_init(&advdata, NULL, &options, on_adv_evt, NULL);
    APP_ERROR_CHECK(err_code);
}

/**@brief Function for initializing buttons and leds.
 *
 * @param[out] p_erase_bonds  Will be true if the clear bonding button was pressed to wake the application up.
 */
static void buttons_leds_init(bool * p_erase_bonds)
{
    bsp_event_t startup_event;

    uint32_t err_code = bsp_init(BSP_INIT_LED | BSP_INIT_BUTTONS,
                                 APP_TIMER_TICKS(100, APP_TIMER_PRESCALER),
                                 bsp_event_handler);

    APP_ERROR_CHECK(err_code);

    err_code = bsp_btn_ble_init(NULL, &startup_event);
    APP_ERROR_CHECK(err_code);

    *p_erase_bonds = (startup_event == BSP_EVENT_CLEAR_BONDING_DATA);
}

/**@brief Function for the Power manager.
 */
static void power_manage(void)
{
    uint32_t err_code = sd_app_evt_wait();

    APP_ERROR_CHECK(err_code);
}
//十六进制转字符
uint8_t HexToChar(uint8_t temp)
{
    uint8_t dst;
    if (temp < 10)
		{
        dst = temp + '0';
    }else
		{
        dst = temp -10 +'A';
    }
    return dst;
}
//16进制数组转换为字符串数组
void HexToString(uint8_t *pbDest, uint8_t *pbSrc, uint16_t nLen)
{
    uint16_t i;  

    for (i=0; i<nLen; i++)
    {
        pbDest[i*2] = HexToChar(pbSrc[i] / 16);
        pbDest[i*2+1] = HexToChar(pbSrc[i] % 16);
    }
}
//saadc回调函数
void saadc_callback(nrf_drv_saadc_evt_t const *p_event)
{
	  ret_code_t err_code;
	  uint8_t adc_result[SAMPLES_IN_BUFFER*2],adc_string[SAMPLES_IN_BUFFER*4];
	  if(p_event->type == NRF_DRV_SAADC_EVT_DONE)
		{
		    //设置好缓存，为下一次采样做准备
			  err_code=nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer,
			                                        SAMPLES_IN_BUFFER);
			   APP_ERROR_CHECK(err_code);
			   //读取采样结果，使用串口发送
			   for(uint32_t i=0;i<p_event->data.done.size;i++)
			   {
            adc_result[(i*2)] = p_event->data.done.p_buffer[i] >> 8;
            adc_result[(i*2)+1] = p_event->data.done.p_buffer[i];
			   }
				 				//将采样结果转换为字符串数组，这么做的目的是为了让nRF CONNECT应用能显示出数据，否则直接发送16进制数据的话，显示的是乱码
				HexToString(adc_string,adc_result,SAMPLES_IN_BUFFER*2);
        //BLE传输的数据长度不能超过20个字节
				if(SAMPLES_IN_BUFFER <= 5)
        {
            //发送数据
					  ble_nus_string_send(&m_nus, &adc_string[0], SAMPLES_IN_BUFFER*4);
        }
		 }
}
//SAADC初始化函数
void saadc_init(void)
{
	ret_code_t err_code;
	//定义SAADC采样通道0初始化配置结构体变量,并用默认参数初始化
	nrf_saadc_channel_config_t channel_0_config=
	    NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN2);
	channel_0_config.gain=NRF_SAADC_GAIN1_6;
	channel_0_config.reference=NRF_SAADC_REFERENCE_INTERNAL;  //使用内部的0.6V作为参考电压

	//定义SAADC采样通道1初始化配置结构体，并用默认参数初始化
		nrf_saadc_channel_config_t channel_1_config=
	    NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN0);
	channel_1_config.gain=NRF_SAADC_GAIN1_6;
	channel_1_config.reference=NRF_SAADC_REFERENCE_INTERNAL;  //使用内部的0.6V作为参考电压

	//定义SAADC采样通道2初始化配置结构体
	nrf_saadc_channel_config_t channel_2_config=
	    NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(SAADC_CH_PSELP_PSELP_VDD);

	channel_2_config.gain=NRF_SAADC_GAIN1_6;
	channel_2_config.reference=NRF_SAADC_REFERENCE_INTERNAL;  //使用内部的0.6V作为参考电压

	//初始化SAADC
	err_code=nrf_drv_saadc_init(NULL,saadc_callback);
  APP_ERROR_CHECK(err_code);

	//初始化SAADC的通道0
	err_code = nrf_drv_saadc_channel_init(0, &channel_0_config);
  APP_ERROR_CHECK(err_code);

  err_code = nrf_drv_saadc_channel_init(1, &channel_1_config);
  APP_ERROR_CHECK(err_code);

  err_code = nrf_drv_saadc_channel_init(2, &channel_2_config);
  APP_ERROR_CHECK(err_code);

	//使用双缓存
	//设置好第一个缓存
	err_code=nrf_drv_saadc_buffer_convert(m_buffer_pool,SAMPLES_IN_BUFFER);
	APP_ERROR_CHECK(err_code);
//	//设置好第二个缓存
//	err_code=nrf_drv_saadc_buffer_convert(m_buffer_pool[1],SAMPLES_IN_BUFFER);
//	APP_ERROR_CHECK(err_code);
}
/**@brief Function for starting advertising.
 */
static void advertising_start(void)
{
    uint32_t err_code = ble_advertising_start(BLE_ADV_MODE_FAST);

    APP_ERROR_CHECK(err_code);
}
//串口事件回调函数
void uart_event_handle(app_uart_evt_t * p_event)
{
    static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
    static uint8_t index = 0;
    uint32_t       err_code;

    switch (p_event->evt_type)
    {
        case APP_UART_DATA_READY:  //串口数据接收事件
            UNUSED_VARIABLE(app_uart_get(&data_array[index]));
            index++;
				    printf("receive data\r\n");
				    //判断数据是否接收完成，这里接收完成的标志是"\n"或者字节数大于20
            if ((data_array[index - 1] == '\n') || (index >= (BLE_NUS_MAX_DATA_LEN)))
            {

							  err_code = ble_nus_string_send(&m_nus, data_array, index);

							  if (err_code != NRF_ERROR_INVALID_STATE)
                {
                    APP_ERROR_CHECK(err_code);
                }

                index = 0;
            }
            break;

        case APP_UART_COMMUNICATION_ERROR:  //通讯错误事件
            APP_ERROR_HANDLER(p_event->data.error_communication);
            break;

        case APP_UART_FIFO_ERROR:  //FIFO错误事件
            APP_ERROR_HANDLER(p_event->data.error_code);
            break;

        default:
            break;
    }
}

//串口初始化程序
static void uart_init()
{
    uint32_t                     err_code;
    const app_uart_comm_params_t comm_params =
    {
        RX_PIN_NUMBER,
        TX_PIN_NUMBER,
        RTS_PIN_NUMBER,
        CTS_PIN_NUMBER,
        APP_UART_FLOW_CONTROL_DISABLED,
        false,
        UART_BAUDRATE_BAUDRATE_Baud115200
    };

    APP_UART_FIFO_INIT( &comm_params,
                       UART_RX_BUF_SIZE,
                       UART_TX_BUF_SIZE,
                       uart_event_handle,
                       APP_IRQ_PRIORITY_LOWEST,
                       err_code);
    APP_ERROR_CHECK(err_code);
}

//定时器2初始化函数
static void timers2_init()
{
	  uint32_t time_ms=1000;
	  uint32_t time_ticks=0;
    uint32_t err_code=NRF_SUCCESS;

	  //定义定时器配置结构体，并使用默认配置参数初始化结构体
	  nrf_drv_timer_config_t timer_cfg=NRF_DRV_TIMER_DEFAULT_CONFIG;
	  timer_cfg.frequency = NRF_TIMER_FREQ_31250Hz;
	  //初始化定时器，初始化时会注册事件回调函数
	  err_code=nrf_drv_timer_init(&m_timer,&timer_cfg,saadc_sampling_timeout_handler);
	  APP_ERROR_CHECK(err_code);
	  //定时时间ms转化为ticks
	  time_ticks=nrf_drv_timer_ms_to_ticks(&m_timer,time_ms);
	  //设置定时器捕获/比较通道及该通道的比较值，使能通道的比较中断
	  nrf_drv_timer_extended_compare(&m_timer,NRF_TIMER_CC_CHANNEL0,time_ticks,
	                                 NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK,true);
	  //启动定时器
	  nrf_drv_timer_enable(&m_timer);
}
//PPI初始化函数
void ppi_config(void)
{
    uint32_t err_code=NRF_SUCCESS;

	  //初始化PPI程序模块
	  err_code=nrf_drv_ppi_init();
	  APP_ERROR_CHECK(err_code);

	  //分配PPI通道，注意PPI的通道分配是驱动函数完成的，分配的通道号保存到my_ppi_channel
	  err_code=nrf_drv_ppi_channel_alloc(&my_ppi_channel);
    APP_ERROR_CHECK(err_code);

	  //分配PPI通道的EEP和TEP
	  err_code=nrf_drv_ppi_channel_assign(my_ppi_channel,
           nrf_drv_timer_compare_event_address_get(&m_timer, NRF_TIMER_CC_CHANNEL0),
	         nrf_drv_saadc_sample_task_get());
	  APP_ERROR_CHECK(err_code);

	  //使能PPI通道
	  err_code=nrf_drv_ppi_channel_enable(my_ppi_channel);
	  APP_ERROR_CHECK(err_code);

}
/**@brief Function for application main entry.
 */
int main(void)
{
    uint32_t err_code;
    bool     erase_bonds;

    // Initialize.
    err_code = NRF_LOG_INIT(NULL);
    APP_ERROR_CHECK(err_code);

	  uart_init();  //串口初始化程序
    timers_init();//定时器初始化
	  timers2_init();  //定时器2初始化

	  buttons_leds_init(&erase_bonds);//板卡外设的初始化
    ble_stack_init();
    peer_manager_init(erase_bonds);//配对管理器
    if (erase_bonds == true)
    {
        NRF_LOG_INFO("Bonds erased!\r\n");
    }
    gap_params_init();  //GAP层初始化
    advertising_init();  //广播配置
    services_init();
    conn_params_init();

    // Start execution.
    NRF_LOG_INFO("Template started\r\n");
    saadc_init();  //SAADC初始化函数
		application_timers_start();  //开始定时器
    err_code = ble_advertising_start(BLE_ADV_MODE_FAST);
    APP_ERROR_CHECK(err_code);
    ppi_config();

    // Enter main loop.
    for (;;)
    {
        if (NRF_LOG_PROCESS() == false)
        {
            power_manage();
        }
    }
}

/**
 * @}
 */

注意

1 设置的定时时间不要超过定时器的最大定时时间，如果超过最大定时时间，可以修改定时器的频率，如下这行语句修改了定时器的频率

timer_cfg.frequency = NRF_TIMER_FREQ_31250Hz;

2 定时器初始化时

	  nrf_drv_timer_config_t timer_cfg=NRF_DRV_TIMER_DEFAULT_CONFIG;
	  timer_cfg.frequency=NRF_TIMER_FREQ_31250Hz;

其中NRF_DRV_TIMER_DEFAULT_CONFIG宏用来初始化定时器，可以查看一下该宏的定义

#define NRF_DRV_TIMER_DEFAULT_CONFIG \
{                                                                               \
    .frequency          = (nrf_timer_frequency_t)TIMER_DEFAULT_CONFIG_FREQUENCY,\
    .mode               = (nrf_timer_mode_t)TIMER_DEFAULT_CONFIG_MODE,          \
    .bit_width          = (nrf_timer_bit_width_t)TIMER_DEFAULT_CONFIG_BIT_WIDTH,\
    .interrupt_priority = TIMER_DEFAULT_CONFIG_IRQ_PRIORITY,                    \
    .p_context          = NULL                                                  \
}

在NRF_DRV_TIMER_DEFAULT_CONFIG宏中初始化了Timer的时钟频率，Timer的工作模式(定时或计数)，Timer的位宽，Timer的中断优先级等。以位宽为例，TIMER_DEFAULT_CONFIG_BIT_WIDTH的定义可以在sdk_config.h中查看到。

// <o> TIMER_DEFAULT_CONFIG_BIT_WIDTH  - Timer counter bit width

// <0=> 16 bit
// <1=> 8 bit
// <2=> 24 bit
// <3=> 32 bit 

#ifndef TIMER_DEFAULT_CONFIG_BIT_WIDTH
#define TIMER_DEFAULT_CONFIG_BIT_WIDTH 0
#endif

Timer的位宽可以设置为16bit，8bit，24bit，32bit。

参考资料

1 nRF52832 API

2 艾克姆科技资料