SD GATT procedure (2) failed on connection handle 0 with error: 0x0000000D.

Hello, everyone
I used NRF52832 as the center and tried to connect to a peripheral, but after connecting for a fixed period of time, the center would actively disconnect from the peripheral. This problem is inevitable. This seems to be the result of an abnormal connector? And unfortunately, I couldn't fix the problem by modifying the peripheral configuration, only by modifying the center code.
The central application code is very simple, just a serial port passthrough service, and handles AT instructions from the serial port.
I provided the sniffer's log file, the center's main code file, and the Soc's log file.
Thank you

<info> app: result=AT+CONN, cmp_len=7, ok_count=7, leng=21, at_code=7

<debug> ble_scan: Filter set on address 0x

<debug> ble_scan:  B6 FF 93 37 1D CA      |...7..  

<debug> ble_scan: Scanning

<debug> ble_scan: Connecting

<debug> ble_scan: Connection status: 0

<debug> nrf_ble_gatt: Requesting to update ATT MTU to 247 bytes on connection 0x0.

<debug> nrf_ble_gatt: Updating data length to 251 on connection 0x0.

<info> app: Connecting to target B6FF93371DCA

<debug> nrf_ble_gq: Purging request queue with id: 0

<debug> nrf_ble_gq: Registering connection handle: 0x0000

<debug> ble_db_disc: Starting discovery of service with UUID 0xAE30 on connection handle 0x0.

<debug> nrf_ble_gq: Adding item to the request queue

<debug> nrf_ble_gq: GATTC Primary Services Discovery Request

<debug> nrf_ble_gq: SD is currently busy. The GATT request procedure will be attempted                       again later.

<debug> nrf_ble_gq: Processing the request queue...

<debug> nrf_ble_gq: GATTC Primary Service Discovery Request

<debug> nrf_ble_gq: SD is currently busy. The GATT request procedure will be attempted                           again later.

<debug> nrf_ble_gatt: Data length updated to 27 on connection 0x0.

<debug> nrf_ble_gatt: max_rx_octets: 27

<debug> nrf_ble_gatt: max_tx_octets: 27

<debug> nrf_ble_gatt: max_rx_time: 328

<debug> nrf_ble_gatt: max_tx_time: 328

<debug> nrf_ble_gq: Processing the request queue...

<debug> nrf_ble_gq: GATTC Primary Service Discovery Request

<error> nrf_ble_gq: SD GATT procedure (2) failed on connection handle 0 with error: 0x0000000D.

<debug> app: GATT Client Timeout.

<info> app: Disconnected.

<info> app: Disconnected. conn_handle: 0x0, reason: 0x16
<info> app: result=AT+CONN, cmp_len=7, ok_count=7, leng=21, at_code=7

<debug> ble_scan: Filter set on address 0x

<debug> ble_scan:  B6 FF 93 37 1D CA      |...7..  

<debug> ble_scan: Scanning

<debug> ble_scan: Connecting

<debug> ble_scan: Connection status: 0

<debug> nrf_ble_gatt: Requesting to update ATT MTU to 247 bytes on connection 0x0.

<debug> nrf_ble_gatt: Updating data length to 251 on connection 0x0.

<info> app: Connecting to target B6FF93371DCA

<debug> nrf_ble_gq: Purging request queue with id: 0

<debug> nrf_ble_gq: Registering connection handle: 0x0000

<debug> ble_db_disc: Starting discovery of service with UUID 0xAE30 on connection handle 0x0.

<debug> nrf_ble_gq: Adding item to the request queue

<debug> nrf_ble_gq: GATTC Primary Services Discovery Request

<debug> nrf_ble_gq: SD is currently busy. The GATT request procedure will be attempted                       again later.

<debug> nrf_ble_gq: Processing the request queue...

<debug> nrf_ble_gq: GATTC Primary Service Discovery Request

<debug> nrf_ble_gq: SD is currently busy. The GATT request procedure will be attempted                           again later.

<debug> nrf_ble_gatt: Data length updated to 27 on connection 0x0.

<debug> nrf_ble_gatt: max_rx_octets: 27

<debug> nrf_ble_gatt: max_tx_octets: 27

<debug> nrf_ble_gatt: max_rx_time: 328

<debug> nrf_ble_gatt: max_tx_time: 328

<debug> nrf_ble_gq: Processing the request queue...

<debug> nrf_ble_gq: GATTC Primary Service Discovery Request

<error> nrf_ble_gq: SD GATT procedure (2) failed on connection handle 0 with error: 0x0000000D.

<debug> app: GATT Client Timeout.

<info> app: Disconnected.

<info> app: Disconnected. conn_handle: 0x0, reason: 0x16
DW2AT-R.pcapng
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 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
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 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
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 *    Nordic Semiconductor ASA integrated circuit.
 *
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include "nordic_common.h"
#include "app_error.h"
#include "app_uart.h"
#include "ble_db_discovery.h"
#include "app_timer.h"
#include "app_util.h"
#include "bsp_btn_ble.h"
#include "ble.h"
#include "ble_gap.h"
#include "ble_hci.h"
#include "nrf_sdh.h"
#include "nrf_sdh_ble.h"
#include "nrf_sdh_soc.h"
#include "ble_nus_c.h"
#include "nrf_ble_gatt.h"
#include "nrf_pwr_mgmt.h"
#include "nrf_ble_scan.h"

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#include "ble_conn_state.h"

#include "at_cmd.h"


#define VERSION_STRING_APP	"ver:V1.0.0 build:"__DATE__" "__TIME__


static uint32_t find_adv_name(const ble_gap_evt_adv_report_t *p_adv_report, uint8_t *p_name);
static void AT_SCNT_Handler(uint8_t *p_data, uint16_t data_len);
static void AT_SCAN_Handler(uint8_t *p_data, uint16_t data_len);
static void AT_COMI_Handler(uint8_t *p_data, uint16_t data_len);
static void AT_COMA_Handler(uint8_t *p_data, uint16_t data_len);
static void AT_COLA_Handler(uint8_t *p_data, uint16_t data_len);
static void AT_COSU_Handler(uint8_t *p_data, uint16_t data_len);
static void AT_CONN_Handler(uint8_t *p_data, uint16_t data_len);
static void AT_CONC_Handler(uint8_t *p_data, uint16_t data_len);
static void AT_DISC_Handler(uint8_t *p_data, uint16_t data_len);
static void AT_DATA_Handler(uint8_t *p_data, uint16_t data_len);
static void AT_VERS_Handler(uint8_t *p_data, uint16_t data_len);
static void AT_TEST_Handler(uint8_t *p_data, uint16_t data_len);




#define APP_BLE_CONN_CFG_TAG    1                                       /**< Tag that refers to the BLE stack configuration set with @ref sd_ble_cfg_set. The default tag is @ref BLE_CONN_CFG_TAG_DEFAULT. */
#define APP_BLE_OBSERVER_PRIO   3                                       /**< BLE observer priority of the application. There is no need to modify this value. */

#define UART_TX_BUF_SIZE        256                                     /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE        256                                     /**< UART RX buffer size. */

#define NUS_SERVICE_UUID_TYPE   BLE_UUID_TYPE_VENDOR_BEGIN              /**< UUID type for the Nordic UART Service (vendor specific). */

#define ECHOBACK_BLE_UART_DATA  0                                       /**< Echo the UART data that is received over the Nordic UART Service (NUS) back to the sender. */


BLE_NUS_C_ARRAY_DEF(m_ble_nus_c, NRF_SDH_BLE_CENTRAL_LINK_COUNT);                                             /**< BLE Nordic UART Service (NUS) client instance. */
NRF_BLE_GATT_DEF(m_gatt);                                               /**< GATT module instance. */
BLE_DB_DISCOVERY_ARRAY_DEF(m_db_disc, NRF_SDH_BLE_CENTRAL_LINK_COUNT);                                        /**< Database discovery module instance. */
NRF_BLE_SCAN_DEF(m_scan);                                               /**< Scanning Module instance. */
NRF_BLE_GQ_DEF(m_ble_gatt_queue,                                        /**< BLE GATT Queue instance. */
               NRF_SDH_BLE_CENTRAL_LINK_COUNT,
               NRF_BLE_GQ_QUEUE_SIZE);

static uint16_t m_ble_nus_max_data_len = BLE_GATT_ATT_MTU_DEFAULT - OPCODE_LENGTH - HANDLE_LENGTH; /**< Maximum length of data (in bytes) that can be transmitted to the peer by the Nordic UART service module. */

#define SCAN_NAME_BUFFER_SIZE	(NRF_BLE_SCAN_NAME_MAX_LEN)	/*��ʱ�洢�㲥���֣�*/
#define SCAN_TIMEOUT_DEFAULT	(500)/**< Scan timeout in 10 ms units. @sa BLE_GAP_SCAN_TIMEOUT. */
static ble_gap_scan_params_t m_scan_param =
{
    .active        = 0x01,
    .interval      = NRF_BLE_SCAN_SCAN_INTERVAL,
    .window        = NRF_BLE_SCAN_SCAN_WINDOW,
    .filter_policy = BLE_GAP_SCAN_FP_ACCEPT_ALL,
    .timeout       = SCAN_TIMEOUT_DEFAULT,
    .scan_phys     = BLE_GAP_PHY_1MBPS,// 1 Mbps PHY
};
static ble_gap_conn_params_t m_conn_param =
{
  .min_conn_interval 	= (uint16_t)MSEC_TO_UNITS(NRF_BLE_SCAN_MIN_CONNECTION_INTERVAL, UNIT_1_25_MS),         /**< Minimum Connection Interval in 1.25 ms units, see @ref BLE_GAP_CP_LIMITS.*/
  .max_conn_interval 	= (uint16_t)MSEC_TO_UNITS(NRF_BLE_SCAN_MAX_CONNECTION_INTERVAL, UNIT_1_25_MS),         /**< Maximum Connection Interval in 1.25 ms units, see @ref BLE_GAP_CP_LIMITS.*/
  .slave_latency 		= (uint16_t)NRF_BLE_SCAN_SLAVE_LATENCY,             /**< Slave Latency in number of connection events, see @ref BLE_GAP_CP_LIMITS.*/
  .conn_sup_timeout 	= (uint16_t)MSEC_TO_UNITS(NRF_BLE_SCAN_SUPERVISION_TIMEOUT, UNIT_10_MS),          /**< Connection Supervision Timeout in 10 ms units, see @ref BLE_GAP_CP_LIMITS.*/
};




#define UART_TIMER_TIMEOUT (30)
APP_TIMER_DEF(m_uart_rx_tmr);

static uint8_t uart_rx_buf[BLE_NUS_MAX_DATA_LEN];
static uint8_t uart_rx_index = 0;
static uint16_t uart_rx_leng = 0;

/* at command define */
static volatile uint8_t at_received = 0;	//at data has received
static volatile at_code_typ at_process = AT_NULL;
at_member_str const at_member_array[] = {
	{AT_COMI, AT_COMI_CODE},
	{AT_COMA, AT_COMA_CODE},
	{AT_COLA, AT_COLA_CODE},
	{AT_COSU, AT_COSU_CODE},
	{AT_SCNT, AT_SCNT_CODE},
	{AT_SCAN, AT_SCAN_CODE},
	{AT_CONN, AT_CONN_CODE},
	{AT_CONC, AT_CONC_CODE},
	{AT_DISC, AT_DISC_CODE},
	{AT_DATA, AT_DATA_CODE},
	{AT_VERS, AT_VERS_CODE},
	{AT_TEST, AT_TEST_CODE},
	{NULL, AT_NULL}
};

/* current connection param define */
struct curr_conn_param_str {
	uint8_t channel;
	uint8_t filter_address[6];
} curr_conn_param = {0, 0, 0, 0, 0, 0, 0};

uint16_t conn_handle_array[2] = {BLE_CONN_HANDLE_INVALID,BLE_CONN_HANDLE_INVALID};

#define GET_CHANNEL_INDEX_BY_BLE_NUS_C(conn_handle_) (m_ble_nus_c[0].conn_handle == conn_handle_)?(0):(1)
#define GET_CHANNEL_INDEX_BY_CONN_HANDLE_ARR(conn_handle_) (conn_handle_array[0] == conn_handle_)?(0):(1)
#define GET_CHANNEL_ACTIVE(channel_) (m_ble_nus_c[channel_].conn_handle == BLE_CONN_HANDLE_INVALID)?(0):(1)


/**@brief NUS UUID. 
static ble_uuid_t const m_nus_uuid =
{
    .uuid = BLE_UUID_NUS_SERVICE,
    .type = NUS_SERVICE_UUID_TYPE
};*/
/*
static uint8_t const m_name[] = "OTC Clarity Units-R";
static uint8_t const m_address[] = {0x11, 0x00, 0x40, 0x37, 0x03, 0x80};
*/

/**@brief Function for handling asserts in the SoftDevice.
 *
 * @details This function is called in case of an assert in the SoftDevice.
 *
 * @warning This handler is only an example and is not meant for the 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] p_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(0xDEADBEEF, line_num, p_file_name);
}


/**@brief Function for handling the Nordic UART Service Client errors.
 *
 * @param[in]   nrf_error   Error code containing information about what went wrong.
 */
static void nus_error_handler(uint32_t nrf_error)
{
    APP_ERROR_HANDLER(nrf_error);
}
/*
static uint8_t const m_name_l[] = "OTC Clarity Units-L";
static uint8_t const m_address_l[] = {0x10, 0x00, 0x40, 0x37, 0x03, 0x80};
static void scan_reconfig(void)
{
	ret_code_t          err_code;
	
	nrf_ble_scan_stop();
	
	nrf_ble_scan_filters_disable(&m_scan);

	nrf_ble_scan_all_filter_remove(&m_scan);

    err_code = nrf_ble_scan_filter_set(&m_scan, SCAN_NAME_FILTER, m_name_l);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_NAME_FILTER, false);
    APP_ERROR_CHECK(err_code);	
	
	
    err_code = nrf_ble_scan_filter_set(&m_scan, SCAN_ADDR_FILTER, m_address_l);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_ADDR_FILTER, false);
    APP_ERROR_CHECK(err_code);	
}
*/

/**@brief Function to start scanning. */
static void scan_start(void)
{
    ret_code_t ret;

    ret = nrf_ble_scan_start(&m_scan);
    APP_ERROR_CHECK(ret);

//    ret = bsp_indication_set(BSP_INDICATE_SCANNING);
//    APP_ERROR_CHECK(ret);
}

//�����豸��ַ
void device_stor(ble_nus_c_t * p_ble_nus_c,ble_gap_evt_connected_t const * p_addr)
{
	p_ble_nus_c->addr.addr[0] = p_addr->peer_addr.addr[0];
	p_ble_nus_c->addr.addr[1] = p_addr->peer_addr.addr[1];
	p_ble_nus_c->addr.addr[2] = p_addr->peer_addr.addr[2];
	p_ble_nus_c->addr.addr[3] = p_addr->peer_addr.addr[3];
	p_ble_nus_c->addr.addr[4] = p_addr->peer_addr.addr[4];
	p_ble_nus_c->addr.addr[5] = p_addr->peer_addr.addr[5];
}
/**@brief Function for handling Scanning Module events.
 */
static void scan_evt_handler(scan_evt_t const * p_scan_evt)
{
    ret_code_t err_code;

    switch(p_scan_evt->scan_evt_id)
    {
         case NRF_BLE_SCAN_EVT_CONNECTING_ERROR:
         {
              err_code = p_scan_evt->params.connecting_err.err_code;
              APP_ERROR_CHECK(err_code);
				if (at_process == AT_CONN_CODE)
				{
					printf("OK+CONNE\r\n");
					at_process = AT_NULL;			 	
				}	              
         } break;

         case NRF_BLE_SCAN_EVT_CONNECTED:
         {
              ble_gap_evt_connected_t const * p_connected =
                               p_scan_evt->params.connected.p_connected;
			  //device_stor(&m_ble_nus_c[p_scan_evt->params.connected.conn_handle],p_connected);
			  device_stor(&m_ble_nus_c[curr_conn_param.channel],p_connected);
             // Scan is automatically stopped by the connection.
             NRF_LOG_INFO("Connecting to target %02x%02x%02x%02x%02x%02x",
                      p_connected->peer_addr.addr[0],
                      p_connected->peer_addr.addr[1],
                      p_connected->peer_addr.addr[2],
                      p_connected->peer_addr.addr[3],
                      p_connected->peer_addr.addr[4],
                      p_connected->peer_addr.addr[5]
                      );

            if (at_process == AT_CONN_CODE)
            {
            	printf("OK+CONN%dS\r\n", curr_conn_param.channel);
            	at_process = AT_NULL;
            }
         } break;

         case NRF_BLE_SCAN_EVT_SCAN_TIMEOUT:
         {
             NRF_LOG_INFO("Scan timed out.");
             if (at_process == AT_SCAN_CODE)
			 {
				if ((GET_CHANNEL_ACTIVE(0)) || (GET_CHANNEL_ACTIVE(1)))
				{
					if (GET_CHANNEL_ACTIVE(0))
					{
						bsp_indication_set(BSP_INDICATE_USER_SCANNER_END_ONLY_1);
					}
					else
					{
						bsp_indication_set(BSP_INDICATE_USER_SCANNER_END_ONLY_0);
					}
				}
				else
				{
					bsp_indication_set(BSP_INDICATE_USER_SCANNER_END);
				}			 
				 printf("OK+SCANE\r\n");
				 at_process = AT_NULL;
			 }
			 if (at_process == AT_CONN_CODE)
			 {
				if (curr_conn_param.channel)
				{
					bsp_indication_set(BSP_INDICATE_USER_SCANNER_END_ONLY_1);
				}
				else
				{
					bsp_indication_set(BSP_INDICATE_USER_SCANNER_END_ONLY_0);
				}			 
            	printf("OK+CONNF\r\n");
            	at_process = AT_NULL;			 	
			 }			 
         } break;
		 case NRF_BLE_SCAN_EVT_NOT_FOUND:
			 if (at_process == AT_SCAN_CODE)
			 {
				 uint8_t name_buffer[SCAN_NAME_BUFFER_SIZE];
				 memset(name_buffer, 0, SCAN_NAME_BUFFER_SIZE);
				 ble_gap_evt_adv_report_t const * p_adv = p_scan_evt->params.p_not_found;					 
				 if(find_adv_name(p_adv, name_buffer) != NRF_SUCCESS)
				 {
					 memset(name_buffer, 0, SCAN_NAME_BUFFER_SIZE);
				 }
				 else
				 {
					 printf("OK+SCAN%02X%02X%02X%02X%02X%02X:%d:%s\r\n",
						p_adv->peer_addr.addr[0],
						p_adv->peer_addr.addr[1],
						p_adv->peer_addr.addr[2],
						p_adv->peer_addr.addr[3],
						p_adv->peer_addr.addr[4],
						p_adv->peer_addr.addr[5],
						p_adv->rssi,
						name_buffer
					 );
				 }
			 }
			 break;

         default:
             break;
    }
}


/**@brief Function for initializing the scanning and setting the filters.
 */
static void scan_init(bool use_filter)
{
    ret_code_t          err_code;
    nrf_ble_scan_init_t init_scan;

    memset(&init_scan, 0, sizeof(init_scan));
	
    init_scan.connect_if_match = use_filter;
    init_scan.conn_cfg_tag     = APP_BLE_CONN_CFG_TAG;
	init_scan.p_scan_param     = &m_scan_param;
	init_scan.p_conn_param     = &m_conn_param;

    err_code = nrf_ble_scan_init(&m_scan, &init_scan, scan_evt_handler);
    APP_ERROR_CHECK(err_code);
	
	if (use_filter)
	{
		err_code = nrf_ble_scan_filter_set(&m_scan, SCAN_ADDR_FILTER, curr_conn_param.filter_address);
		APP_ERROR_CHECK(err_code);

		err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_ADDR_FILTER, false);
		APP_ERROR_CHECK(err_code);		
	}
	else
	{
		err_code = nrf_ble_scan_filters_disable(&m_scan);
		APP_ERROR_CHECK(err_code);
		
		err_code = nrf_ble_scan_all_filter_remove(&m_scan);
		APP_ERROR_CHECK(err_code);
	}
/*
    err_code = nrf_ble_scan_filter_set(&m_scan, SCAN_NAME_FILTER, m_name);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_NAME_FILTER, false);
    APP_ERROR_CHECK(err_code);	
	
	
    err_code = nrf_ble_scan_filter_set(&m_scan, SCAN_ADDR_FILTER, m_address);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_ADDR_FILTER, false);
    APP_ERROR_CHECK(err_code);
*/
	
	/*
    err_code = nrf_ble_scan_filter_set(&m_scan, SCAN_UUID_FILTER, &m_nus_uuid);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_scan_filters_enable(&m_scan, NRF_BLE_SCAN_UUID_FILTER, false);
    APP_ERROR_CHECK(err_code);
	*/
}


/**@brief Function for handling database discovery events.
 *
 * @details This function is a callback function to handle events from the database discovery module.
 *          Depending on the UUIDs that are discovered, this function forwards the events
 *          to their respective services.
 *
 * @param[in] p_event  Pointer to the database discovery event.
 */
static void db_disc_handler(ble_db_discovery_evt_t * p_evt)
{
    //ble_nus_c_on_db_disc_evt(&m_ble_nus_c[p_evt->conn_handle], p_evt);
    ble_nus_c_on_db_disc_evt(&m_ble_nus_c[GET_CHANNEL_INDEX_BY_BLE_NUS_C(p_evt->conn_handle)], p_evt);
}


/**@brief Function for handling characters received by the Nordic UART Service (NUS).
 *
 * @details This function takes a list of characters of length data_len and prints the characters out on UART.
 *          If @ref ECHOBACK_BLE_UART_DATA is set, the data is sent back to sender.
 */
static void ble_nus_chars_received_uart_print(uint8_t * p_data, uint16_t data_len, uint8_t channel)
{
    ret_code_t ret_val;

    NRF_LOG_DEBUG("Receiving data.");
    NRF_LOG_HEXDUMP_DEBUG(p_data, data_len);

    printf("OK+DATA%d:%d:", channel, data_len);
    for (uint32_t i = 0; i < data_len; i++)
    {
        do
        {
            ret_val = app_uart_put(p_data[i]);
            if ((ret_val != NRF_SUCCESS) && (ret_val != NRF_ERROR_BUSY))
            {
                NRF_LOG_ERROR("app_uart_put failed for index 0x%04x.", i);
                APP_ERROR_CHECK(ret_val);
            }
        } while (ret_val == NRF_ERROR_BUSY);
    }
    if (ECHOBACK_BLE_UART_DATA)
    {
		/*
        // Send data back to the peripheral.
        do
        {
            ret_val = ble_nus_c_string_send(&m_ble_nus_c, p_data, data_len);
            if ((ret_val != NRF_SUCCESS) && (ret_val != NRF_ERROR_BUSY))
            {
                NRF_LOG_ERROR("Failed sending NUS message. Error 0x%x. ", ret_val);
                APP_ERROR_CHECK(ret_val);
            }
        } while (ret_val == NRF_ERROR_BUSY);*/
    }
}


/**@brief   Function for handling app_uart events.
 *
 * @details This function receives a single character from the app_uart module and appends it to
 *          a string. The string is sent over BLE when the last character received is a
 *          'new line' '\n' (hex 0x0A) or if the string reaches the maximum data length.
 */
void uart_event_handle(app_uart_evt_t * p_event)
{
    switch (p_event->evt_type)
    {
        /**@snippet [Handling data from UART] */
        case APP_UART_DATA_READY:
			if ((at_process == AT_NULL) && (at_received == 0) && (uart_rx_index < sizeof(uart_rx_buf)))
			{
				UNUSED_VARIABLE(app_uart_get(&uart_rx_buf[uart_rx_index++]));
				APP_ERROR_CHECK(app_timer_start(m_uart_rx_tmr, APP_TIMER_TICKS(UART_TIMER_TIMEOUT), NULL));
			}
            break;

        /**@snippet [Handling data from UART] */
        case APP_UART_COMMUNICATION_ERROR:
            NRF_LOG_ERROR("Communication error occurred while handling UART.");
            APP_ERROR_HANDLER(p_event->data.error_communication);
            break;

        case APP_UART_FIFO_ERROR:
            NRF_LOG_ERROR("Error occurred in FIFO module used by UART.");
            APP_ERROR_HANDLER(p_event->data.error_code);
            break;

        default:
            break;
    }
}


/**@brief Callback handling Nordic UART Service (NUS) client events.
 *
 * @details This function is called to notify the application of NUS client events.
 *
 * @param[in]   p_ble_nus_c   NUS client handle. This identifies the NUS client.
 * @param[in]   p_ble_nus_evt Pointer to the NUS client event.
 */

/**@snippet [Handling events from the ble_nus_c module] */
static void ble_nus_c_evt_handler(ble_nus_c_t * p_ble_nus_c, ble_nus_c_evt_t const * p_ble_nus_evt)
{
    ret_code_t err_code;

    switch (p_ble_nus_evt->evt_type)
    {
        case BLE_NUS_C_EVT_DISCOVERY_COMPLETE:
            NRF_LOG_INFO("Discovery complete.");
            err_code = ble_nus_c_handles_assign(p_ble_nus_c, p_ble_nus_evt->conn_handle, &p_ble_nus_evt->handles);
            APP_ERROR_CHECK(err_code);

            err_code = ble_nus_c_tx_notif_enable(p_ble_nus_c);
            APP_ERROR_CHECK(err_code);
            NRF_LOG_INFO("Connected to device with Nordic UART Service.");
            break;

        case BLE_NUS_C_EVT_NUS_TX_EVT:
			NRF_LOG_INFO("receive data for mac: %02X %02X %02X %02X %02X %02X\r\n",
							p_ble_nus_c->addr.addr[0],
							p_ble_nus_c->addr.addr[1],
							p_ble_nus_c->addr.addr[2],
							p_ble_nus_c->addr.addr[3],
							p_ble_nus_c->addr.addr[4],
							p_ble_nus_c->addr.addr[5]
							);        
            ble_nus_chars_received_uart_print(p_ble_nus_evt->p_data, p_ble_nus_evt->data_len, GET_CHANNEL_INDEX_BY_BLE_NUS_C(p_ble_nus_c->conn_handle));
            break;

        case BLE_NUS_C_EVT_DISCONNECTED:
            NRF_LOG_INFO("Disconnected.");
           // scan_start();
            break;
    }
}
/**@snippet [Handling events from the ble_nus_c module] */


/**
 * @brief Function for handling shutdown events.
 *
 * @param[in]   event       Shutdown type.
 */
static bool shutdown_handler(nrf_pwr_mgmt_evt_t event)
{
    ret_code_t err_code;

    err_code = bsp_indication_set(BSP_INDICATE_IDLE);
    APP_ERROR_CHECK(err_code);

    switch (event)
    {
        case NRF_PWR_MGMT_EVT_PREPARE_WAKEUP:
            // Prepare wakeup buttons.
            err_code = bsp_btn_ble_sleep_mode_prepare();
            APP_ERROR_CHECK(err_code);
            break;

        default:
            break;
    }

    return true;
}

NRF_PWR_MGMT_HANDLER_REGISTER(shutdown_handler, APP_SHUTDOWN_HANDLER_PRIORITY);


/**@brief Function for handling BLE events.
 *
 * @param[in]   p_ble_evt   Bluetooth stack event.
 * @param[in]   p_context   Unused.
 */
static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
    ret_code_t            err_code;
    ble_gap_evt_t const * p_gap_evt = &p_ble_evt->evt.gap_evt;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:
        	APP_ERROR_CHECK_BOOL(p_gap_evt->conn_handle < NRF_SDH_BLE_CENTRAL_LINK_COUNT);

            //err_code = ble_nus_c_handles_assign(&m_ble_nus_c[p_gap_evt->conn_handle], p_ble_evt->evt.gap_evt.conn_handle, NULL);
            err_code = ble_nus_c_handles_assign(&m_ble_nus_c[curr_conn_param.channel], p_ble_evt->evt.gap_evt.conn_handle, NULL);
            APP_ERROR_CHECK(err_code);
            
            conn_handle_array[curr_conn_param.channel] = p_ble_evt->evt.gap_evt.conn_handle;

            err_code = bsp_indication_set((curr_conn_param.channel)?(BSP_INDICATE_USER_CHANNEL_1_ACTIVE):(BSP_INDICATE_USER_CHANNEL_0_ACTIVE));
            APP_ERROR_CHECK(err_code);

            // start discovery of services. The NUS Client waits for a discovery result
            //err_code = ble_db_discovery_start(&m_db_disc[p_gap_evt->conn_handle], p_ble_evt->evt.gap_evt.conn_handle);
            err_code = ble_db_discovery_start(&m_db_disc[curr_conn_param.channel], p_ble_evt->evt.gap_evt.conn_handle);
            APP_ERROR_CHECK(err_code);
/*
            if (ble_conn_state_central_conn_count() == NRF_SDH_BLE_CENTRAL_LINK_COUNT)
            {
            	NRF_LOG_INFO("central counter two!");
            }
            else
            {
//            	scan_reconfig();
//            	scan_start();
            }*/
            
            break;

        case BLE_GAP_EVT_DISCONNECTED:

            NRF_LOG_INFO("Disconnected. conn_handle: 0x%x, reason: 0x%x",
                         p_gap_evt->conn_handle,
                         p_gap_evt->params.disconnected.reason);
            printf("OK+LOST%d:%02X%02X%02X%02X%02X%02X\r\n", GET_CHANNEL_INDEX_BY_CONN_HANDLE_ARR(p_gap_evt->conn_handle), 
            													m_ble_nus_c[GET_CHANNEL_INDEX_BY_CONN_HANDLE_ARR(p_gap_evt->conn_handle)].addr.addr[0],
            													m_ble_nus_c[GET_CHANNEL_INDEX_BY_CONN_HANDLE_ARR(p_gap_evt->conn_handle)].addr.addr[1],
            													m_ble_nus_c[GET_CHANNEL_INDEX_BY_CONN_HANDLE_ARR(p_gap_evt->conn_handle)].addr.addr[2],
            													m_ble_nus_c[GET_CHANNEL_INDEX_BY_CONN_HANDLE_ARR(p_gap_evt->conn_handle)].addr.addr[3],
            													m_ble_nus_c[GET_CHANNEL_INDEX_BY_CONN_HANDLE_ARR(p_gap_evt->conn_handle)].addr.addr[4],
            													m_ble_nus_c[GET_CHANNEL_INDEX_BY_CONN_HANDLE_ARR(p_gap_evt->conn_handle)].addr.addr[5]
            													);
            err_code = bsp_indication_set(
            	(GET_CHANNEL_INDEX_BY_CONN_HANDLE_ARR(p_gap_evt->conn_handle))?
            	(BSP_INDICATE_USER_CHANNEL_1_INVALID):(BSP_INDICATE_USER_CHANNEL_0_INVALID));
            APP_ERROR_CHECK(err_code);            													

            conn_handle_array[GET_CHANNEL_INDEX_BY_CONN_HANDLE_ARR(p_gap_evt->conn_handle)] = BLE_CONN_HANDLE_INVALID;
            
            break;

        case BLE_GAP_EVT_TIMEOUT:
            if (p_gap_evt->params.timeout.src == BLE_GAP_TIMEOUT_SRC_CONN)
            {
                NRF_LOG_INFO("Connection Request timed out.");
            }
			 if (at_process == AT_CONN_CODE)
			 {
	        	printf("OK+CONNF\r\n");
	        	at_process = AT_NULL;			 	
			 }            
            break;

        case BLE_GAP_EVT_SEC_PARAMS_REQUEST:
            // Pairing not supported.
            err_code = sd_ble_gap_sec_params_reply(p_ble_evt->evt.gap_evt.conn_handle, BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP, NULL, NULL);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GAP_EVT_CONN_PARAM_UPDATE_REQUEST:
            // Accepting parameters requested by peer.
            err_code = sd_ble_gap_conn_param_update(p_gap_evt->conn_handle,
                                                    &p_gap_evt->params.conn_param_update_request.conn_params);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
        {
            NRF_LOG_DEBUG("PHY update request.");
            ble_gap_phys_t const phys =
            {
                .rx_phys = BLE_GAP_PHY_AUTO,
                .tx_phys = BLE_GAP_PHY_AUTO,
            };
            err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
            APP_ERROR_CHECK(err_code);
        } break;

        case BLE_GATTC_EVT_TIMEOUT:
            // Disconnect on GATT Client timeout event.
            NRF_LOG_DEBUG("GATT Client Timeout.");
            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;

        case BLE_GATTS_EVT_TIMEOUT:
            // Disconnect on GATT Server timeout event.
            NRF_LOG_DEBUG("GATT Server Timeout.");
            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;

        default:
            break;
    }
}


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

    err_code = nrf_sdh_enable_request();
    APP_ERROR_CHECK(err_code);

    // Configure the BLE stack using the default settings.
    // Fetch the start address of the application RAM.
    uint32_t ram_start = 0;
    err_code = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start);
    APP_ERROR_CHECK(err_code);

    // Enable BLE stack.
    err_code = nrf_sdh_ble_enable(&ram_start);
    APP_ERROR_CHECK(err_code);

    // Register a handler for BLE events.
    NRF_SDH_BLE_OBSERVER(m_ble_observer, APP_BLE_OBSERVER_PRIO, ble_evt_handler, NULL);
}


/**@brief Function for handling events from the GATT library. */
void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt)
{
    if (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED)
    {
        NRF_LOG_INFO("ATT MTU exchange completed.");

        m_ble_nus_max_data_len = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
        NRF_LOG_INFO("Ble NUS max data length set to 0x%X(%d)", m_ble_nus_max_data_len, m_ble_nus_max_data_len);
    }
}


/**@brief Function for initializing the GATT library. */
void gatt_init(void)
{
    ret_code_t err_code;

    err_code = nrf_ble_gatt_init(&m_gatt, gatt_evt_handler);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_gatt_att_mtu_central_set(&m_gatt, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling events from the BSP module.
 *
 * @param[in] event  Event generated by button press.
 */
void bsp_event_handler(bsp_event_t event)
{
  //  ret_code_t err_code;

    switch (event)
    {
        case BSP_EVENT_SLEEP:
            nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_GOTO_SYSOFF);
            break;

        case BSP_EVENT_DISCONNECT:
			/*
            err_code = sd_ble_gap_disconnect(m_ble_nus_c.conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            if (err_code != NRF_ERROR_INVALID_STATE)
            {
                APP_ERROR_CHECK(err_code);
            }
			*/
            break;

        default:
            break;
    }
}


/**@brief Handle events from leds timer.
 *
 * @note Timer handler does not support returning an error code.
 * Errors from bsp_led_indication() are not propagated.
 *
 * @param[in]   p_context   parameter registered in timer start function.
 */

static void uart_timer_handler(void * p_context)
{
    UNUSED_PARAMETER(p_context);

	uart_rx_leng = uart_rx_index;
	uart_rx_index = 0;
	at_received = 1;
}

/**@brief Function for initializing the UART. */
static void uart_init(void)
{
    ret_code_t err_code;

    app_uart_comm_params_t const comm_params =
    {
        .rx_pin_no    = RX_PIN_NUMBER,
        .tx_pin_no    = TX_PIN_NUMBER,
        .rts_pin_no   = RTS_PIN_NUMBER,
        .cts_pin_no   = CTS_PIN_NUMBER,
        .flow_control = APP_UART_FLOW_CONTROL_DISABLED,
        .use_parity   = false,
        .baud_rate    = 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);
	
	err_code = app_timer_create(&m_uart_rx_tmr, APP_TIMER_MODE_SINGLE_SHOT, uart_timer_handler);
	APP_ERROR_CHECK(err_code);	  
}

/**@brief Function for initializing the Nordic UART Service (NUS) client. */
static void nus_c_init(void)
{
    ret_code_t       err_code;
    ble_nus_c_init_t init;

    init.evt_handler   = ble_nus_c_evt_handler;
    init.error_handler = nus_error_handler;
    init.p_gatt_queue  = &m_ble_gatt_queue;

    for (uint32_t i = 0; i < NRF_SDH_BLE_CENTRAL_LINK_COUNT; i++)
    {
	    err_code = ble_nus_c_init(&m_ble_nus_c[i], &init);
	    APP_ERROR_CHECK(err_code);    	
    }
}


/**@brief Function for initializing leds. */
static void leds_init(void)
{
    ret_code_t err_code;
    //bsp_event_t startup_event;

    err_code = bsp_init(BSP_INIT_LEDS, bsp_event_handler);
    APP_ERROR_CHECK(err_code);

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


/**@brief Function for initializing the timer. */
static void timer_init(void)
{
    ret_code_t err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for initializing the nrf log module. */
static void log_init(void)
{
    ret_code_t err_code = NRF_LOG_INIT(NULL);
    APP_ERROR_CHECK(err_code);

    NRF_LOG_DEFAULT_BACKENDS_INIT();
}


/**@brief Function for initializing power management.
 */
static void power_management_init(void)
{
    ret_code_t err_code;
    err_code = nrf_pwr_mgmt_init();
    APP_ERROR_CHECK(err_code);
}


/** @brief Function for initializing the database discovery module. */
static void db_discovery_init(void)
{
    ble_db_discovery_init_t db_init;

    memset(&db_init, 0, sizeof(ble_db_discovery_init_t));

    db_init.evt_handler  = db_disc_handler;
    db_init.p_gatt_queue = &m_ble_gatt_queue;

    ret_code_t err_code = ble_db_discovery_init(&db_init);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling the idle state (main loop).
 *
 * @details Handles any pending log operations, then sleeps until the next event occurs.
 */
static void idle_state_handle(void)
{
    if (NRF_LOG_PROCESS() == false)
    {
        //nrf_pwr_mgmt_run();
    }
}


static at_code_typ at_get_code(void *param, uint16_t leng)
{
	at_code_typ code = AT_NULL;
	uint16_t ok_count;
	uint16_t cmp_leng;
	uint8_t *p_at_str;
	uint8_t *p_param;	
	if (at_received)
	{
		at_member_str *p_at_member = (at_member_str *)at_member_array;
		while (p_at_member->string != NULL)
		{
			ok_count = 0;
			cmp_leng = 0;
			p_at_str = (uint8_t *)p_at_member->string;
			p_param = (uint8_t *)param;
			while ((*p_at_str != '\0') && (cmp_leng < leng))
			{
				cmp_leng++;
				if (*p_at_str++ == *p_param++)
				{
					ok_count++;
				}
				else
				{
					break;
				}
			}
			if (ok_count == strlen((const char *)p_at_member->string))
			{
				code = p_at_member->code;
				NRF_LOG_INFO("result=%s, cmp_len=%d, ok_count=%d, leng=%d, at_code=%d", p_at_member->string, cmp_leng, ok_count, leng, code);
				break;				
			}

			p_at_member++;
		}
		
		at_received = 0;
	}
	
	return code;
}

static void uart_puts(uint8_t *p_data, uint16_t data_len)
{
	ret_code_t ret_val;

	for (uint32_t i = 0; i < data_len; i++)
	{
		do
		{
			ret_val = app_uart_put(p_data[i]);
			if ((ret_val != NRF_SUCCESS) && (ret_val != NRF_ERROR_BUSY))
			{
				NRF_LOG_ERROR("app_uart_put failed for index 0x%04x.", i);
				APP_ERROR_CHECK(ret_val);
			}
		} while (ret_val == NRF_ERROR_BUSY);
	}
}


static uint32_t find_adv_name(const ble_gap_evt_adv_report_t *p_adv_report, uint8_t *p_name)
{
	uint8_t i;
	uint32_t  index = 0;
	uint8_t * p_data;

	p_data = p_adv_report->data.p_data;

	while (index < p_adv_report->data.len)
	{
	  uint8_t field_length = p_data[index];
	  uint8_t field_type   = p_data[index + 1];

	  if ((field_type == BLE_GAP_AD_TYPE_COMPLETE_LOCAL_NAME) || (field_type == BLE_GAP_AD_TYPE_SHORT_LOCAL_NAME))
	  {
		  for(i=0;i<field_length-1;i++)
		  {
			  *p_name++ = p_data[index+2+i];
			  if (i >= SCAN_NAME_BUFFER_SIZE - 1)
				  break;
		  }
		  return NRF_SUCCESS;
	  }
	  index += field_length + 1;
	}
	return NRF_ERROR_NOT_FOUND;
}




int main(void)
{
    // Initialize.
    log_init();
    timer_init();
    uart_init();
    leds_init();
    db_discovery_init();
    power_management_init();
    ble_stack_init();
    gatt_init();
    nus_c_init();
    scan_init(false);

    // Start execution.
	
    printf("BLE UART central example started. zsl:%s\r\n", __TIME__);
    NRF_LOG_INFO("BLE UART central example started. zsl:%s", __TIME__);
    //scan_start();
	
	
    // Enter main loop.
    for (;;)
    {
        idle_state_handle();
		
		if (at_process == AT_NULL)
		{
			at_process = at_get_code(uart_rx_buf, uart_rx_leng);
			switch(at_process)
			{
				case AT_COMI_CODE:
					AT_COMI_Handler(uart_rx_buf, uart_rx_leng);
					break;
				case AT_COMA_CODE:
					AT_COMA_Handler(uart_rx_buf, uart_rx_leng);
					break;
				case AT_COLA_CODE:
					AT_COLA_Handler(uart_rx_buf, uart_rx_leng);
					break;
				case AT_COSU_CODE:
					AT_COSU_Handler(uart_rx_buf, uart_rx_leng);
					break;
				case AT_SCNT_CODE:
					AT_SCNT_Handler(uart_rx_buf, uart_rx_leng);
					break;
				case AT_SCAN_CODE:
					AT_SCAN_Handler(uart_rx_buf, uart_rx_leng);
					break;
				case AT_CONN_CODE:
					AT_CONN_Handler(uart_rx_buf, uart_rx_leng);
					break;
				case AT_CONC_CODE:
					AT_CONC_Handler(uart_rx_buf, uart_rx_leng);
					break;
				case AT_DISC_CODE:
					AT_DISC_Handler(uart_rx_buf, uart_rx_leng);
					break;
				case AT_DATA_CODE:
					AT_DATA_Handler(uart_rx_buf, uart_rx_leng);
					break;
				case AT_VERS_CODE:
					AT_VERS_Handler(uart_rx_buf, uart_rx_leng);
					break;
				case AT_TEST_CODE:
					AT_TEST_Handler(uart_rx_buf, uart_rx_leng);
					break;				
				default:break;
			}
		}

    }
}





/******************************
AT+SCNT[P]
P: [1~ 9] [?]
*****************************/
static void AT_SCNT_Handler(uint8_t *p_data, uint16_t data_len)
{
	uint8_t param = *(p_data + sizeof(AT_SCNT) - 1);
	
	if (data_len <= (sizeof(AT_SCNT) - 1))
	{
		at_process = AT_NULL;
		return;
	}
	
	if (param == '?')
	{
		printf("OK+Get:%d\r\n", m_scan_param.timeout/100);
	}
	else if ((param >= '1') && (param <= '9'))
	{
		m_scan_param.timeout = (param - '0')*100;
		nrf_ble_scan_stop();
		scan_init(false);
		printf("OK+Set:%d\r\n", m_scan_param.timeout/100);
	}
	
	at_process = AT_NULL;
}


static void AT_SCAN_Handler(uint8_t *p_data, uint16_t data_len)
{
	if ((GET_CHANNEL_ACTIVE(0)) && (GET_CHANNEL_ACTIVE(1)))
	{
		at_process = AT_NULL;
		return;		
	}
	
	printf("OK+SCANS\r\n");
	if ((GET_CHANNEL_ACTIVE(0)) || (GET_CHANNEL_ACTIVE(1)))
	{
		if (GET_CHANNEL_ACTIVE(0))
		{
			bsp_indication_set(BSP_INDICATE_USER_SCANNER_START_ONLY_1);
		}
		else
		{
			bsp_indication_set(BSP_INDICATE_USER_SCANNER_START_ONLY_0);
		}
	}
	else
	{
		bsp_indication_set(BSP_INDICATE_USER_SCANNER_START);
	}
	scan_init(false);
	scan_start();	
}


static void AT_COMI_Handler(uint8_t *p_data, uint16_t data_len)
{
	int8_t interval = 0;
	uint8_t param = *(p_data + sizeof(AT_COMI) - 1);
	
	if (data_len <= (sizeof(AT_SCNT) - 1))
	{
		at_process = AT_NULL;
		return;
	}
	
	if (param == '?')
	{
		switch (m_conn_param.min_conn_interval)
		{
			case (uint16_t)MSEC_TO_UNITS(7.5, UNIT_1_25_MS):interval = 0;break;
			case (uint16_t)MSEC_TO_UNITS(10, UNIT_1_25_MS):interval = 1;break;
			case (uint16_t)MSEC_TO_UNITS(15, UNIT_1_25_MS):interval = 2;break;
			case (uint16_t)MSEC_TO_UNITS(20, UNIT_1_25_MS):interval = 3;break;
			case (uint16_t)MSEC_TO_UNITS(25, UNIT_1_25_MS):interval = 4;break;
			case (uint16_t)MSEC_TO_UNITS(30, UNIT_1_25_MS):interval = 5;break;
			case (uint16_t)MSEC_TO_UNITS(35, UNIT_1_25_MS):interval = 6;break;
			case (uint16_t)MSEC_TO_UNITS(40, UNIT_1_25_MS):interval = 7;break;
			case (uint16_t)MSEC_TO_UNITS(45, UNIT_1_25_MS):interval = 8;break;
			case (uint16_t)MSEC_TO_UNITS(60, UNIT_1_25_MS):interval = 9;break;
			default:interval = -1;break;
		}
		printf("OK+Get:%d\r\n", interval);
	}
	else if ((param >= '0') && (param <= '9'))
	{
		switch (param)
		{
			case '0':m_conn_param.min_conn_interval = (uint16_t)MSEC_TO_UNITS(7.5, UNIT_1_25_MS);break;
			case '1':m_conn_param.min_conn_interval = (uint16_t)MSEC_TO_UNITS(10, UNIT_1_25_MS);break;
			case '2':m_conn_param.min_conn_interval = (uint16_t)MSEC_TO_UNITS(15, UNIT_1_25_MS);break;
			case '3':m_conn_param.min_conn_interval = (uint16_t)MSEC_TO_UNITS(20, UNIT_1_25_MS);break;
			case '4':m_conn_param.min_conn_interval = (uint16_t)MSEC_TO_UNITS(25, UNIT_1_25_MS);break;
			case '5':m_conn_param.min_conn_interval = (uint16_t)MSEC_TO_UNITS(30, UNIT_1_25_MS);break;
			case '6':m_conn_param.min_conn_interval = (uint16_t)MSEC_TO_UNITS(35, UNIT_1_25_MS);break;
			case '7':m_conn_param.min_conn_interval = (uint16_t)MSEC_TO_UNITS(40, UNIT_1_25_MS);break;
			case '8':m_conn_param.min_conn_interval = (uint16_t)MSEC_TO_UNITS(45, UNIT_1_25_MS);break;
			case '9':m_conn_param.min_conn_interval = (uint16_t)MSEC_TO_UNITS(60, UNIT_1_25_MS);break;
			default:
				m_conn_param.min_conn_interval = (uint16_t)MSEC_TO_UNITS(NRF_BLE_SCAN_MIN_CONNECTION_INTERVAL, UNIT_1_25_MS);
				break;
		}
		nrf_ble_scan_stop();
		scan_init(false);
		printf("OK+Set:%d\r\n", param-'0');		
	}
	
	at_process = AT_NULL;
}


static void AT_COMA_Handler(uint8_t *p_data, uint16_t data_len)
{
	int8_t interval = 0;
	uint8_t param = *(p_data + sizeof(AT_COMA) - 1);
	
	if (data_len <= (sizeof(AT_SCNT) - 1))
	{
		at_process = AT_NULL;
		return;
	}
	
	if (param == '?')
	{
		switch (m_conn_param.max_conn_interval)
		{
			case (uint16_t)MSEC_TO_UNITS(7.5, UNIT_1_25_MS):interval = 0;break;
			case (uint16_t)MSEC_TO_UNITS(10, UNIT_1_25_MS):interval = 1;break;
			case (uint16_t)MSEC_TO_UNITS(15, UNIT_1_25_MS):interval = 2;break;
			case (uint16_t)MSEC_TO_UNITS(20, UNIT_1_25_MS):interval = 3;break;
			case (uint16_t)MSEC_TO_UNITS(25, UNIT_1_25_MS):interval = 4;break;
			case (uint16_t)MSEC_TO_UNITS(30, UNIT_1_25_MS):interval = 5;break;
			case (uint16_t)MSEC_TO_UNITS(35, UNIT_1_25_MS):interval = 6;break;
			case (uint16_t)MSEC_TO_UNITS(40, UNIT_1_25_MS):interval = 7;break;
			case (uint16_t)MSEC_TO_UNITS(45, UNIT_1_25_MS):interval = 8;break;
			case (uint16_t)MSEC_TO_UNITS(60, UNIT_1_25_MS):interval = 9;break;
			default:interval = -1;break;
		}
		printf("OK+Get:%d\r\n", interval);
	}
	else if ((param >= '0') && (param <= '9'))
	{
		switch (param)
		{
			case '0':m_conn_param.max_conn_interval = (uint16_t)MSEC_TO_UNITS(7.5, UNIT_1_25_MS);break;
			case '1':m_conn_param.max_conn_interval = (uint16_t)MSEC_TO_UNITS(10, UNIT_1_25_MS);break;
			case '2':m_conn_param.max_conn_interval = (uint16_t)MSEC_TO_UNITS(15, UNIT_1_25_MS);break;
			case '3':m_conn_param.max_conn_interval = (uint16_t)MSEC_TO_UNITS(20, UNIT_1_25_MS);break;
			case '4':m_conn_param.max_conn_interval = (uint16_t)MSEC_TO_UNITS(25, UNIT_1_25_MS);break;
			case '5':m_conn_param.max_conn_interval = (uint16_t)MSEC_TO_UNITS(30, UNIT_1_25_MS);break;
			case '6':m_conn_param.max_conn_interval = (uint16_t)MSEC_TO_UNITS(35, UNIT_1_25_MS);break;
			case '7':m_conn_param.max_conn_interval = (uint16_t)MSEC_TO_UNITS(40, UNIT_1_25_MS);break;
			case '8':m_conn_param.max_conn_interval = (uint16_t)MSEC_TO_UNITS(45, UNIT_1_25_MS);break;
			case '9':m_conn_param.max_conn_interval = (uint16_t)MSEC_TO_UNITS(60, UNIT_1_25_MS);break;
			default:
				m_conn_param.max_conn_interval = (uint16_t)MSEC_TO_UNITS(NRF_BLE_SCAN_MAX_CONNECTION_INTERVAL, UNIT_1_25_MS);
				break;
		}
		nrf_ble_scan_stop();
		scan_init(false);
		printf("OK+Set:%d\r\n", param-'0');		
	}
	
	at_process = AT_NULL;
}


static void AT_COLA_Handler(uint8_t *p_data, uint16_t data_len)
{
	if (data_len <= (sizeof(AT_SCNT) - 1))
	{
		at_process = AT_NULL;
		return;
	}
	
	if (*(p_data + sizeof(AT_COLA) - 1) == '?')
	{
		printf("OK+Get:%d\r\n", m_conn_param.slave_latency);
	}
	else
	{
		uint32_t latency;
		int result;
		uint8_t buffer[4] = {0,0,0,0};

		memcpy(buffer, (p_data + sizeof(AT_COLA) - 1), data_len - sizeof(AT_COLA) + 1);
		
		result = sscanf((const char *)buffer, "%d", &latency);

		if ((latency <= BLE_GAP_CP_SLAVE_LATENCY_MAX) && (result == 1))
		{
			m_conn_param.slave_latency = latency;
			nrf_ble_scan_stop();
			scan_init(false);
			printf("OK+Set:%d\r\n", m_conn_param.slave_latency);			
		}
	}
	
	at_process = AT_NULL;	
}


static void AT_COSU_Handler(uint8_t *p_data, uint16_t data_len)
{
	int8_t timeout;
	uint8_t param = *(p_data + sizeof(AT_COSU) - 1);
	
	if (data_len <= (sizeof(AT_SCNT) - 1))
	{
		at_process = AT_NULL;
		return;
	}
	
	if (param == '?')
	{
		switch (m_conn_param.conn_sup_timeout)
		{
			case (uint16_t)MSEC_TO_UNITS(100, UNIT_10_MS):timeout = 0;break;
			case (uint16_t)MSEC_TO_UNITS(1000, UNIT_10_MS):timeout = 1;break;
			case (uint16_t)MSEC_TO_UNITS(2000, UNIT_10_MS):timeout = 2;break;
			case (uint16_t)MSEC_TO_UNITS(3000, UNIT_10_MS):timeout = 3;break;
			case (uint16_t)MSEC_TO_UNITS(4000, UNIT_10_MS):timeout = 4;break;
			case (uint16_t)MSEC_TO_UNITS(5000, UNIT_10_MS):timeout = 5;break;
			case (uint16_t)MSEC_TO_UNITS(6000, UNIT_10_MS):timeout = 6;break;
			default:timeout = -1;break;
		}
		printf("OK+Get:%d\r\n", timeout);
	}
	else if ((param >= '0') && (param <= '6'))
	{
		if (param == '0')
		{
			m_conn_param.conn_sup_timeout = (uint16_t)MSEC_TO_UNITS(100, UNIT_10_MS);
		}
		else if((param >= '1') && (param <= '6'))
		{
			m_conn_param.conn_sup_timeout = (uint16_t)MSEC_TO_UNITS((param-'0')*1000, UNIT_10_MS);
		}
		nrf_ble_scan_stop();
		scan_init(false);
		
		printf("OK+Set:%d\r\n", param - '0');
	}
	
	at_process = AT_NULL;	
}



static void AT_CONN_Handler(uint8_t *p_data, uint16_t data_len)
{
	uint32_t channel;
	uint32_t address[6];
	int result;
	
	if (data_len < (sizeof(AT_CONN"0:010203040506") - 1))
	{
		goto flag_error;
	}
	
	//extract
	result = sscanf((const char *)p_data, "AT+CONN%d:%02X%02X%02X%02X%02X%02X",
																&channel,
																&address[0],
																&address[1],
																&address[2],
																&address[3],
																&address[4],
																&address[5]);
	if (result != 7)
	{
		goto flag_error;
	}
	
	if (channel == 0)
	{
		curr_conn_param.channel = 0;
	}
	else if (channel == 1)
	{
		curr_conn_param.channel = 1;
	}
	else
	{
		goto flag_error;
	}

	curr_conn_param.filter_address[0] = address[0];
	curr_conn_param.filter_address[1] = address[1];
	curr_conn_param.filter_address[2] = address[2];
	curr_conn_param.filter_address[3] = address[3];
	curr_conn_param.filter_address[4] = address[4];
	curr_conn_param.filter_address[5] = address[5];
	
	if (m_ble_nus_c[curr_conn_param.channel].conn_handle != BLE_CONN_HANDLE_INVALID)
	{
		goto flag_error;
	}

	if (curr_conn_param.channel)
	{
		bsp_indication_set(BSP_INDICATE_USER_SCANNER_START_ONLY_1);
	}
	else
	{
		bsp_indication_set(BSP_INDICATE_USER_SCANNER_START_ONLY_0);
	}	

	// connecting target
	printf("OK+CONN%dA\r\n", curr_conn_param.channel); //report connecting
	scan_init(true);
	scan_start();
	return;
	flag_error:
	at_process = AT_NULL;
}



static void AT_CONC_Handler(uint8_t *p_data, uint16_t data_len)
{
	uint8_t channel;
	
	if (data_len < (sizeof(AT_CONC"0") - 1))
	{
		goto flag_error;
	}

	if (*(p_data + 7) == '0')
	{
		channel = 0;
	}
	else if(*(p_data + 7) == '1')
	{
		channel = 1;
	}
	else
	{
		goto flag_error;
	}

	if (m_ble_nus_c[channel].conn_handle == BLE_CONN_HANDLE_INVALID)
	{
		printf("OK+CON0\r\n");
	}
	else
	{
		printf("OK+CON1:%02X%02X%02X%02X%02X%02X\r\n",
			m_ble_nus_c[channel].addr.addr[0],
			m_ble_nus_c[channel].addr.addr[1],
			m_ble_nus_c[channel].addr.addr[2],
			m_ble_nus_c[channel].addr.addr[3],
			m_ble_nus_c[channel].addr.addr[4],
			m_ble_nus_c[channel].addr.addr[5]);
	}

	flag_error:
	at_process = AT_NULL;	
}


static void AT_DISC_Handler(uint8_t *p_data, uint16_t data_len)
{
	uint8_t channel;
	ret_code_t err_code;
	
	if (data_len < (sizeof(AT_DISC"0") - 1))
	{
		goto flag_error;
	}

	if (*(p_data + 7) == '0')
	{
		channel = 0;
	}
	else if(*(p_data + 7) == '1')
	{
		channel = 1;
	}
	else
	{
		goto flag_error;
	}

	if (m_ble_nus_c[channel].conn_handle == BLE_CONN_HANDLE_INVALID)
	{
		goto flag_error;
	}

	err_code = sd_ble_gap_disconnect(m_ble_nus_c[channel].conn_handle,
									 BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
	if (err_code != NRF_ERROR_INVALID_STATE)
	{
		APP_ERROR_CHECK(err_code);
		goto flag_error;
	}

	printf("OK+DISC%d\r\n", channel);

	flag_error:
	at_process = AT_NULL;
}



static void AT_DATA_Handler(uint8_t *p_data, uint16_t data_len)
{
	uint32_t channel;
	uint32_t length;
	int result;
	uint8_t *p_send_data;
	uint8_t counter = 0;
	uint32_t ret_val;
	
	if (data_len < (sizeof(AT_DATA"0:0:") - 1))
	{
		goto flag_error;
	}

	result = sscanf((const char *)p_data, "AT+DATA%d:%d:", &channel, &length);

	NRF_LOG_INFO("sscanf result:%d, channel:%d, length:%d\r\n", result, channel, length);

	p_send_data = p_data + sizeof("AT+DATA0:") - 1;

	
	while ((*p_send_data++ != ':') && (++counter <= length));

    do
    {
        ret_val = ble_nus_c_string_send(&m_ble_nus_c[channel], p_send_data, length);
        if ( (ret_val != NRF_ERROR_INVALID_STATE) && (ret_val != NRF_ERROR_RESOURCES) )
        {
            APP_ERROR_CHECK(ret_val);
        }
    } while (ret_val == NRF_ERROR_RESOURCES);

	flag_error:
	at_process = AT_NULL;
}


static void AT_VERS_Handler(uint8_t *p_data, uint16_t data_len)
{
	printf("OK+Get:%s\r\n", VERSION_STRING_APP);
	at_process = AT_NULL;
}


static void AT_TEST_Handler(uint8_t *p_data, uint16_t data_len)
{
	uart_puts("OK\r\n", sizeof("OK\r\n")-1);
	at_process = AT_NULL;
}

/**
 * Copyright (c) 2012 - 2021, Nordic Semiconductor ASA
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 *
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
 *
 * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "sdk_common.h"
#if NRF_MODULE_ENABLED(BLE_NUS_C)
#include <stdlib.h>

#include "ble.h"
#include "ble_nus_c.h"
#include "ble_gattc.h"
#include "ble_srv_common.h"
#include "app_error.h"

#define NRF_LOG_MODULE_NAME ble_nus_c
#include "nrf_log.h"
NRF_LOG_MODULE_REGISTER();


/**@brief Function for intercepting the errors of GATTC and the BLE GATT Queue.
 *
 * @param[in] nrf_error   Error code.
 * @param[in] p_ctx       Parameter from the event handler.
 * @param[in] conn_handle Connection handle.
 */
static void gatt_error_handler(uint32_t   nrf_error,
                               void     * p_ctx,
                               uint16_t   conn_handle)
{
    ble_nus_c_t * p_ble_nus_c = (ble_nus_c_t *)p_ctx;

    NRF_LOG_DEBUG("A GATT Client error has occurred on conn_handle: 0X%X", conn_handle);

    if (p_ble_nus_c->error_handler != NULL)
    {
        p_ble_nus_c->error_handler(nrf_error);
    }
}


void ble_nus_c_on_db_disc_evt(ble_nus_c_t * p_ble_nus_c, ble_db_discovery_evt_t * p_evt)
{
    ble_nus_c_evt_t nus_c_evt;
    memset(&nus_c_evt,0,sizeof(ble_nus_c_evt_t));

    ble_gatt_db_char_t * p_chars = p_evt->params.discovered_db.charateristics;

    // Check if the NUS was discovered.
    if (    (p_evt->evt_type == BLE_DB_DISCOVERY_COMPLETE)
        &&  (p_evt->params.discovered_db.srv_uuid.uuid == BLE_UUID_NUS_SERVICE)
        &&  (p_evt->params.discovered_db.srv_uuid.type == p_ble_nus_c->uuid_type))
    {
        for (uint32_t i = 0; i < p_evt->params.discovered_db.char_count; i++)
        {
            switch (p_chars[i].characteristic.uuid.uuid)
            {
                case BLE_UUID_NUS_RX_CHARACTERISTIC:
                    nus_c_evt.handles.nus_rx_handle = p_chars[i].characteristic.handle_value;        
                    p_ble_nus_c->write_cmd = p_chars[i].characteristic.char_props.write_wo_resp;
                    break;

                case BLE_UUID_NUS_TX_CHARACTERISTIC:
                    nus_c_evt.handles.nus_tx_handle = p_chars[i].characteristic.handle_value;
                    nus_c_evt.handles.nus_tx_cccd_handle = p_chars[i].cccd_handle;
                    break;

                default:
                    break;
            }
        }
        if (p_ble_nus_c->evt_handler != NULL)
        {
            nus_c_evt.conn_handle = p_evt->conn_handle;
            nus_c_evt.evt_type    = BLE_NUS_C_EVT_DISCOVERY_COMPLETE;
            p_ble_nus_c->evt_handler(p_ble_nus_c, &nus_c_evt);
        }
    }
}

/**@brief     Function for handling Handle Value Notification received from the SoftDevice.
 *
 * @details   This function uses the Handle Value Notification received from the SoftDevice
 *            and checks if it is a notification of the NUS TX characteristic from the peer.
 *            If it is, this function decodes the data and sends it to the application.
 *            
 * @param[in] p_ble_nus_c Pointer to the NUS Client structure.
 * @param[in] p_ble_evt   Pointer to the BLE event received.
 */
static void on_hvx(ble_nus_c_t * p_ble_nus_c, ble_evt_t const * p_ble_evt)
{
    // HVX can only occur from client sending.
    if (   (p_ble_nus_c->handles.nus_tx_handle != BLE_GATT_HANDLE_INVALID)
        && (p_ble_evt->evt.gattc_evt.params.hvx.handle == p_ble_nus_c->handles.nus_tx_handle)
        && (p_ble_nus_c->evt_handler != NULL))
    {
        ble_nus_c_evt_t ble_nus_c_evt;

        ble_nus_c_evt.evt_type = BLE_NUS_C_EVT_NUS_TX_EVT;
        ble_nus_c_evt.p_data   = (uint8_t *)p_ble_evt->evt.gattc_evt.params.hvx.data;
        ble_nus_c_evt.data_len = p_ble_evt->evt.gattc_evt.params.hvx.len;

        p_ble_nus_c->evt_handler(p_ble_nus_c, &ble_nus_c_evt);
        NRF_LOG_DEBUG("Client sending data.");
    }
}

uint32_t ble_nus_c_init(ble_nus_c_t * p_ble_nus_c, ble_nus_c_init_t * p_ble_nus_c_init)
{
    uint32_t      err_code;
    ble_uuid_t    uart_uuid;
    ble_uuid128_t nus_base_uuid = NUS_BASE_UUID;

    VERIFY_PARAM_NOT_NULL(p_ble_nus_c);
    VERIFY_PARAM_NOT_NULL(p_ble_nus_c_init);
    VERIFY_PARAM_NOT_NULL(p_ble_nus_c_init->p_gatt_queue);

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

    uart_uuid.type = p_ble_nus_c->uuid_type;
    uart_uuid.uuid = BLE_UUID_NUS_SERVICE;

    p_ble_nus_c->conn_handle           = BLE_CONN_HANDLE_INVALID;
    p_ble_nus_c->evt_handler           = p_ble_nus_c_init->evt_handler;
    p_ble_nus_c->error_handler         = p_ble_nus_c_init->error_handler;
    p_ble_nus_c->handles.nus_tx_handle = BLE_GATT_HANDLE_INVALID;
    p_ble_nus_c->handles.nus_rx_handle = BLE_GATT_HANDLE_INVALID;
    p_ble_nus_c->p_gatt_queue          = p_ble_nus_c_init->p_gatt_queue;

    return ble_db_discovery_evt_register(&uart_uuid);
}

void ble_nus_c_on_ble_evt(ble_evt_t const * p_ble_evt, void * p_context)
{
    ble_nus_c_t * p_ble_nus_c = (ble_nus_c_t *)p_context;

    if ((p_ble_nus_c == NULL) || (p_ble_evt == NULL))
    {
        return;
    }

    if ( (p_ble_nus_c->conn_handle == BLE_CONN_HANDLE_INVALID)
       ||(p_ble_nus_c->conn_handle != p_ble_evt->evt.gap_evt.conn_handle)
       )
    {
        return;
    }

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GATTC_EVT_HVX:
            on_hvx(p_ble_nus_c, p_ble_evt);
            break;

        case BLE_GAP_EVT_DISCONNECTED:
            if (p_ble_evt->evt.gap_evt.conn_handle == p_ble_nus_c->conn_handle
                    && p_ble_nus_c->evt_handler != NULL)
            {
                ble_nus_c_evt_t nus_c_evt;

                nus_c_evt.evt_type = BLE_NUS_C_EVT_DISCONNECTED;

                p_ble_nus_c->conn_handle = BLE_CONN_HANDLE_INVALID;
                p_ble_nus_c->evt_handler(p_ble_nus_c, &nus_c_evt);
            }
            break;

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

/**@brief Function for creating a message for writing to the CCCD. */
static uint32_t cccd_configure(ble_nus_c_t * p_ble_nus_c, bool notification_enable)
{
    nrf_ble_gq_req_t cccd_req;
    uint8_t          cccd[BLE_CCCD_VALUE_LEN];
    uint16_t         cccd_val = notification_enable ? BLE_GATT_HVX_NOTIFICATION : 0;

    memset(&cccd_req, 0, sizeof(nrf_ble_gq_req_t));

    cccd[0] = LSB_16(cccd_val);
    cccd[1] = MSB_16(cccd_val);

    cccd_req.type                        = NRF_BLE_GQ_REQ_GATTC_WRITE;
    cccd_req.error_handler.cb            = gatt_error_handler;
    cccd_req.error_handler.p_ctx         = p_ble_nus_c;
    cccd_req.params.gattc_write.handle   = p_ble_nus_c->handles.nus_tx_cccd_handle;
    cccd_req.params.gattc_write.len      = BLE_CCCD_VALUE_LEN;
    cccd_req.params.gattc_write.offset   = 0;
    cccd_req.params.gattc_write.p_value  = cccd;
    cccd_req.params.gattc_write.write_op = BLE_GATT_OP_WRITE_REQ;
    cccd_req.params.gattc_write.flags    = BLE_GATT_EXEC_WRITE_FLAG_PREPARED_WRITE;

    return nrf_ble_gq_item_add(p_ble_nus_c->p_gatt_queue, &cccd_req, p_ble_nus_c->conn_handle);
}


uint32_t ble_nus_c_tx_notif_enable(ble_nus_c_t * p_ble_nus_c)
{
    VERIFY_PARAM_NOT_NULL(p_ble_nus_c);

    if ( (p_ble_nus_c->conn_handle == BLE_CONN_HANDLE_INVALID)
       ||(p_ble_nus_c->handles.nus_tx_cccd_handle == BLE_GATT_HANDLE_INVALID)
       )
    {
        return NRF_ERROR_INVALID_STATE;
    }
    return cccd_configure(p_ble_nus_c, true);
}


uint32_t ble_nus_c_string_send(ble_nus_c_t * p_ble_nus_c, uint8_t * p_string, uint16_t length)
{
    VERIFY_PARAM_NOT_NULL(p_ble_nus_c);

    nrf_ble_gq_req_t write_req;

    memset(&write_req, 0, sizeof(nrf_ble_gq_req_t));

    if (length > BLE_NUS_MAX_DATA_LEN)
    {
        NRF_LOG_WARNING("Content too long.");
        return NRF_ERROR_INVALID_PARAM;
    }
    if (p_ble_nus_c->conn_handle == BLE_CONN_HANDLE_INVALID)
    {
        NRF_LOG_WARNING("Connection handle invalid.");
        return NRF_ERROR_INVALID_STATE;
    }

    write_req.type                        = NRF_BLE_GQ_REQ_GATTC_WRITE;
    write_req.error_handler.cb            = gatt_error_handler;
    write_req.error_handler.p_ctx         = p_ble_nus_c;
    write_req.params.gattc_write.handle   = p_ble_nus_c->handles.nus_rx_handle;
    write_req.params.gattc_write.len      = length;
    write_req.params.gattc_write.offset   = 0;
    write_req.params.gattc_write.p_value  = p_string;
    write_req.params.gattc_write.write_op = (p_ble_nus_c->write_cmd)?(BLE_GATT_OP_WRITE_CMD):(BLE_GATT_OP_WRITE_REQ);
    write_req.params.gattc_write.flags    = BLE_GATT_EXEC_WRITE_FLAG_PREPARED_WRITE;

    return nrf_ble_gq_item_add(p_ble_nus_c->p_gatt_queue, &write_req, p_ble_nus_c->conn_handle);
}


uint32_t ble_nus_c_handles_assign(ble_nus_c_t               * p_ble_nus,
                                  uint16_t                    conn_handle,
                                  ble_nus_c_handles_t const * p_peer_handles)
{
    VERIFY_PARAM_NOT_NULL(p_ble_nus);

    p_ble_nus->conn_handle = conn_handle;
    if (p_peer_handles != NULL)
    {
        p_ble_nus->handles.nus_tx_cccd_handle = p_peer_handles->nus_tx_cccd_handle;
        p_ble_nus->handles.nus_tx_handle      = p_peer_handles->nus_tx_handle;
        p_ble_nus->handles.nus_rx_handle      = p_peer_handles->nus_rx_handle;
    }
    return nrf_ble_gq_conn_handle_register(p_ble_nus->p_gatt_queue, conn_handle);
}
#endif // NRF_MODULE_ENABLED(BLE_NUS_C)

Parents
  • Hi,

    You are getting a ATT timeout, which we see both from the log and the error code (0xD = NRF_ERROR_TIMEOUT). This makes the nRF disconnect, which is why the disconnect reason is 0x16 = BLE_HCI_LOCAL_HOST_TERMINATED_CONNECTION.

    The sniffer trace shows a connection, then a LL_LENGTH_REQ from the central which gets a LL_UNKNOWN_RSP back, and then just empty packets with a high number of retransmits (odd but not directly related to the disconnect due to ATT timeout). The interesting part here though is the MTU request sent in #48, which is the only ATT transaction in the sniffer trace. The response never comes, and then the disconnect come sin #582, about 30 seconds after the MTU request, which matches the ATT timeout of 30 seconds. So the central disconnects because the peripheral does not respond.

    So everything here points to the issue being in the peripheral. If you are making that, then I would fix the issue in the peripheral. If not, then perhaps you can work around it by sending the MTU request, which you do by not configuring a higher ATT MTU. (Essentially remove the code in your main.c that initiates a MTU exchange and also ensure you don't have any SDK modules that do it, for instance by making sure NRF_BLE_GATT_MTU_EXCHANGE_INITIATION_ENABLED is set to 0 in your sdk_config.h).

  • Hi

    Afterwards, I made a similar attempt: setting up NRF_ BLE_ GATT_ MTU_ EXCHANGE_ INITIATION_ If ENABLED is 0, it will still disconnect (NRF-ERROR_TIMEOUT).
    After the connection was completed, the center immediately did two things: exchanging MTUs and enabling discovery services. After canceling the MTU exchange operation, the center first performed a discovery service after the connection was completed, but the peripheral still did not respond to the center's request. Similarly, due to no response, the center timed out and terminated the connection after a period of time.
    I have come to the conclusion that the first request made by the center immediately after the connection is completed will inevitably not receive a response from the periphery.

    Additionally, I found an interesting phenomenon: you can see from my code that the center can connect up to two peripherals. Amazingly, when this abnormal peripheral is connected as a second device, the peripheral will respond to the first request initiated by the center (MTU exchange or discovery service). When connected as the first device, it will not respond to the host's request. This phenomenon really confuses me.
    After multiple tests and observing the sniffer logs, I found that the host sends the same request packet but does not receive a response from the slave, and the DeltaTime is always less than the other one.
    Why is there such a difference when the second device of the same peripheral as the host is connected?

    List of Documents Attached:
    DW2AT-R-first.pcapng:            Sniffer log, peripheral connected as the first device by the center.
    DW2AT-R-second.pcapng:     Sniffer log, peripheral connected as the second device by the center.
    First_ Connection_ No_ Respond.png:    a screenshot of the file DW2AT-R-first.pcapng
    Second_ Connection_ Respond.png:       a screenshot of the file DW2AT-R-second.pcapng

    DW2AT-R-first.pcapngDW2AT-R-second.pcapng

  • I think this issue can already be focused on two points:
    >When the peripheral is connected to the center as the first device, there is no response to the first request sent by the center after completing the connection. Is this a peripheral issue or a center issue? (For example, because the DeltaTime time is too short, the peripheral cannot process it in a timely manner)
    >When the peripheral is connected to the center as the second device, why is the value difference of DeltaTime so large for the first request issued by the center after completing the connection?

Reply
  • I think this issue can already be focused on two points:
    >When the peripheral is connected to the center as the first device, there is no response to the first request sent by the center after completing the connection. Is this a peripheral issue or a center issue? (For example, because the DeltaTime time is too short, the peripheral cannot process it in a timely manner)
    >When the peripheral is connected to the center as the second device, why is the value difference of DeltaTime so large for the first request issued by the center after completing the connection?

Children
  • Hi

    Due to the summer vacation period we are currently understaffed, so delayed replies must be expected. I am sorry about any inconvenience this might cause. Einar is now out of office, so I will look into this case while he's away.

    As Einar said in his last reply, this seems to be an issue on the peripheral side, where it doesn't seem able to complete an MTU exchange. Are you able to debug to see if there are any error codes indicating what exactly goes wrong within the MTU exchange?

    1. The reason for this disconnect could be because the peripheral tries to call an MTU request when it connects, but the central starts scanning for a new device instead, which could trig a timeout like this.

    2. This is likely because the central has to maintain the connection to the first connected peripheral, so it needs some extra time to connect to the next peripheral.

    Best regards,

    Simon

  • Hi

    After these days of debugging, the main reason is that the peripheral inability to respond to any requests that are immediately initiated by the connection. So I made changes to the completion of the connection:

    >The mtu exchange request cancel (NRF_BLE_GATT_MTU_EXCHANGE_INITIATION_ENABLED set to 0)

    >The discovery service opens after the connection is completed two seconds later.

    Finally can you provide a sample code?? actively initiate the mtu exchange request in the center application.

    I want to actively send mtu exchange requests in the place and time I want in the central application code, but I haven't found the relevant sample code

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