app_usbd_cdc_acm_write multiple write

[kleanthise]

Hello i am using an nrf52840 s140 and i am trying to write a specific event when takes place to the usb port. I am using the usbd_uart example. 

It works fine for the first write command but when i am trying to write for a second time it just writes random stuff.

i am basically updating the value of a characteristic using a counter and i would like that value of the counter to be transferred over to usb virtual port

Looking forward for your help on this

#include "sdk_common.h"
#if NRF_MODULE_ENABLED(BLE_NUS)
#include "ble.h"
#include "ble_nus_custom.h"
#include "ble_srv_common.h"

#define NRF_LOG_MODULE_NAME ble_nus
#if BLE_NUS_CONFIG_LOG_ENABLED
#define NRF_LOG_LEVEL BLE_NUS_CONFIG_LOG_LEVEL
#define NRF_LOG_INFO_COLOR BLE_NUS_CONFIG_INFO_COLOR
#define NRF_LOG_DEBUG_COLOR BLE_NUS_CONFIG_DEBUG_COLOR
#else // BLE_NUS_CONFIG_LOG_ENABLED
#define NRF_LOG_LEVEL 0
#endif // BLE_NUS_CONFIG_LOG_ENABLED
#include "nrf_log.h"
NRF_LOG_MODULE_REGISTER();

#define BLE_UUID_NUS_TX_CHARACTERISTIC 0x0003 /**< The UUID of the TX Characteristic. */
#define BLE_UUID_NUS_RX_CHARACTERISTIC 0x0002 /**< The UUID of the RX Characteristic. */
#define PROGRESS_VALUE_CHAR_UUID 0x0004	      /**< The UUID for Progress Characteristic */
#define RESULTS_VALUE_CHAR_UUID 0x0005	      /**< The UUID for Results Characteristic */

#define BLE_NUS_MAX_RX_CHAR_LEN BLE_NUS_MAX_DATA_LEN /**< Maximum length of the RX Characteristic (in bytes). */
#define BLE_NUS_MAX_TX_CHAR_LEN BLE_NUS_MAX_DATA_LEN /**< Maximum length of the TX Characteristic (in bytes). */

#define NUS_BASE_UUID                                                                                                  \
	{                                                                                                              \
		{                                                                                                      \
			0x9E, 0xCA, 0xDC, 0x24, 0x0E, 0xE5, 0xA9, 0xE0, 0x93, 0xF3, 0xA3, 0xB5, 0x00, 0x00, 0x40, 0x6E \
		}                                                                                                      \
	} /**< Used vendor specific UUID. */

/**@brief Function for handling the @ref BLE_GAP_EVT_CONNECTED event from the SoftDevice.
 *
 * @param[in] p_nus     Nordic UART Service structure.
 * @param[in] p_ble_evt Pointer to the event received from BLE stack.
 */
static void on_connect(ble_nus_t *p_nus, ble_evt_t const *p_ble_evt)
{
	ret_code_t err_code;
	ble_nus_evt_t evt;
	ble_gatts_value_t gatts_val;
	uint8_t cccd_value[2];
	ble_nus_client_context_t *p_client = NULL;

	err_code = blcm_link_ctx_get(p_nus->p_link_ctx_storage,
	    p_ble_evt->evt.gap_evt.conn_handle,
	    (void *)&p_client);
	if (err_code != NRF_SUCCESS) {
		NRF_LOG_ERROR("Link context for 0x%02X connection handle could not be fetched.",
		    p_ble_evt->evt.gap_evt.conn_handle);
	}

	/* Check the hosts CCCD value to inform of readiness to send data using the RX characteristic */
	memset(&gatts_val, 0, sizeof(ble_gatts_value_t));
	gatts_val.p_value = cccd_value;
	gatts_val.len = sizeof(cccd_value);
	gatts_val.offset = 0;

	err_code = sd_ble_gatts_value_get(p_ble_evt->evt.gap_evt.conn_handle,
	    p_nus->tx_handles.cccd_handle,
	    &gatts_val);

	if ((err_code == NRF_SUCCESS) &&
	    (p_nus->data_handler != NULL) &&
	    ble_srv_is_notification_enabled(gatts_val.p_value)) {
		if (p_client != NULL) {
			p_client->is_notification_enabled = true;
		}

		memset(&evt, 0, sizeof(ble_nus_evt_t));
		evt.type = BLE_NUS_EVT_COMM_STARTED;
		evt.p_nus = p_nus;
		evt.conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
		evt.p_link_ctx = p_client;

		p_nus->data_handler(&evt);
	}
}

/**@brief Function for handling the @ref BLE_GATTS_EVT_WRITE event from the SoftDevice.
 *
 * @param[in] p_nus     Nordic UART Service structure.
 * @param[in] p_ble_evt Pointer to the event received from BLE stack.
 */
static void on_write(ble_nus_t *p_nus, ble_evt_t const *p_ble_evt)
{
	ret_code_t err_code;
	ble_nus_evt_t evt;
	ble_nus_client_context_t *p_client;
	ble_gatts_evt_write_t const *p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;

	err_code = blcm_link_ctx_get(p_nus->p_link_ctx_storage,
	    p_ble_evt->evt.gatts_evt.conn_handle,
	    (void *)&p_client);
	if (err_code != NRF_SUCCESS) {
		NRF_LOG_ERROR("Link context for 0x%02X connection handle could not be fetched.",
		    p_ble_evt->evt.gatts_evt.conn_handle);
	}

	memset(&evt, 0, sizeof(ble_nus_evt_t));
	evt.p_nus = p_nus;
	evt.conn_handle = p_ble_evt->evt.gatts_evt.conn_handle;
	evt.p_link_ctx = p_client;

	if ((p_evt_write->handle == p_nus->tx_handles.cccd_handle) &&
	    (p_evt_write->len == 2)) {
		if (p_client != NULL) {
			if (ble_srv_is_notification_enabled(p_evt_write->data)) {
				p_client->is_notification_enabled = true;
				evt.type = BLE_NUS_EVT_COMM_STARTED;
			} else {
				p_client->is_notification_enabled = false;
				evt.type = BLE_NUS_EVT_COMM_STOPPED;
			}

			if (p_nus->data_handler != NULL) {
				p_nus->data_handler(&evt);
			}
		}
	} else if ((p_evt_write->handle == p_nus->rx_handles.value_handle) &&
		   (p_nus->data_handler != NULL)) {
		evt.type = BLE_NUS_EVT_RX_DATA;
		evt.params.rx_data.p_data = p_evt_write->data;
		evt.params.rx_data.length = p_evt_write->len;

		p_nus->data_handler(&evt);
	} else {
		// Do Nothing. This event is not relevant for this service.
	}
}

/**@brief Function for handling the @ref BLE_GATTS_EVT_HVN_TX_COMPLETE event from the SoftDevice.
 *
 * @param[in] p_nus     Nordic UART Service structure.
 * @param[in] p_ble_evt Pointer to the event received from BLE stack.
 */
static void on_hvx_tx_complete(ble_nus_t *p_nus, ble_evt_t const *p_ble_evt)
{
	ret_code_t err_code;
	ble_nus_evt_t evt;
	ble_nus_client_context_t *p_client;

	err_code = blcm_link_ctx_get(p_nus->p_link_ctx_storage,
	    p_ble_evt->evt.gatts_evt.conn_handle,
	    (void *)&p_client);
	if (err_code != NRF_SUCCESS) {
		NRF_LOG_ERROR("Link context for 0x%02X connection handle could not be fetched.",
		    p_ble_evt->evt.gatts_evt.conn_handle);
		return;
	}

	if ((p_client->is_notification_enabled) && (p_nus->data_handler != NULL)) {
		memset(&evt, 0, sizeof(ble_nus_evt_t));
		evt.type = BLE_NUS_EVT_TX_RDY;
		evt.p_nus = p_nus;
		evt.conn_handle = p_ble_evt->evt.gatts_evt.conn_handle;
		evt.p_link_ctx = p_client;

		p_nus->data_handler(&evt);
	}
}

void ble_nus_on_ble_evt(ble_evt_t const *p_ble_evt, void *p_context)
{
	if ((p_context == NULL) || (p_ble_evt == NULL)) {
		return;
	}

	ble_nus_t *p_nus = (ble_nus_t *)p_context;

	switch (p_ble_evt->header.evt_id) {
	case BLE_GAP_EVT_CONNECTED:
		on_connect(p_nus, p_ble_evt);
		break;

	case BLE_GATTS_EVT_WRITE:
		on_write(p_nus, p_ble_evt);
		break;

	case BLE_GATTS_EVT_HVN_TX_COMPLETE:
		on_hvx_tx_complete(p_nus, p_ble_evt);
		break;

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

// Add the RX Characteristic.

static uint32_t rx_char_add(ble_nus_t *p_nus, const ble_nus_init_t *p_nus_init)
{
	uint32_t err_code;
	ble_gatts_char_md_t char_md;
	ble_gatts_attr_md_t cccd_md;
	ble_gatts_attr_md_t attr_md;
	ble_gatts_attr_t attr_char_value;
	ble_uuid_t ble_uuid;

	// Initiliaze the structures
	memset(&cccd_md, 0, sizeof(cccd_md));
	memset(&char_md, 0, sizeof(char_md));
	memset(&attr_md, 0, sizeof(attr_md));
	memset(&attr_char_value, 0, sizeof(attr_char_value));

	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);

	// Client Characteristic Configuration Descriptor metadata.
	cccd_md.vloc = BLE_GATTS_VLOC_STACK; // decide where to store the descriptor (the value of the CCCD), and once again we store it in the SoftDevice controlled part of memory (as we did with the characteristic)
	char_md.char_props.read = 0;	     // Enable read
	char_md.char_props.write = 1;	     // Enable write
	char_md.char_props.write_wo_resp = 1;
	char_md.char_props.notify = 0; // Enable notifications
	char_md.p_char_user_desc = NULL;
	char_md.p_char_pf = NULL;
	char_md.p_user_desc_md = NULL;
	char_md.p_cccd_md = &cccd_md;

	char_md.p_sccd_md = NULL;

	ble_uuid.type = p_nus->uuid_type;
	ble_uuid.uuid = BLE_UUID_NUS_RX_CHARACTERISTIC;

	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);

	attr_md.read_perm = p_nus_init->rx_char_attr_md.read_perm;
	attr_md.write_perm = p_nus_init->rx_char_attr_md.write_perm;
	attr_md.vloc = BLE_GATTS_VLOC_STACK; // BLE_GATTS_VLOC_STACK is the memory location (stack memory) to store the attributes (characteristic)
	attr_md.rd_auth = 0;
	attr_md.wr_auth = 0;
	attr_md.vlen = 0;

	attr_char_value.p_uuid = &ble_uuid;
	attr_char_value.p_attr_md = &attr_md;
	attr_char_value.init_len = sizeof(uint8_t); // sizeof(uint8_t);
	attr_char_value.init_offs = 0;
	attr_char_value.max_len = BLE_NUS_MAX_RX_CHAR_LEN; // sizeof(uint8_t);

	err_code = sd_ble_gatts_characteristic_add(p_nus->service_handle, &char_md, &attr_char_value, &p_nus->rx_handles);
	if (err_code != NRF_SUCCESS) {
		return err_code;
	}

	return NRF_SUCCESS;
}

// Add the TX Characteristic.

static uint32_t tx_char_add(ble_nus_t *p_nus, const ble_nus_init_t *p_nus_init)
{
	uint32_t err_code;
	ble_gatts_char_md_t char_md;
	ble_gatts_attr_md_t cccd_md;
	ble_gatts_attr_md_t attr_md;
	ble_gatts_attr_t attr_char_value;
	ble_uuid_t ble_uuid;

	// Initiliaze the structures
	memset(&cccd_md, 0, sizeof(cccd_md));
	memset(&char_md, 0, sizeof(char_md));
	memset(&attr_md, 0, sizeof(attr_md));
	memset(&attr_char_value, 0, sizeof(attr_char_value));

	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);

	// Client Characteristic Configuration Descriptor metadata.
	cccd_md.vloc = BLE_GATTS_VLOC_STACK; // decide where to store the descriptor (the value of the CCCD), and once again we store it in the SoftDevice controlled part of memory (as we did with the characteristic)
	char_md.char_props.read = 1;	     // Enable read
	char_md.char_props.notify = 1;	     // Enable notifications
	char_md.p_char_user_desc = NULL;
	char_md.p_char_pf = NULL;
	char_md.p_user_desc_md = NULL;
	char_md.p_cccd_md = &cccd_md;

	char_md.p_sccd_md = NULL;

	ble_uuid.type = p_nus->uuid_type;
	ble_uuid.uuid = BLE_UUID_NUS_TX_CHARACTERISTIC;

	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);

	attr_md.read_perm = p_nus_init->tx_char_attr_md.read_perm;
	attr_md.write_perm = p_nus_init->tx_char_attr_md.write_perm;
	attr_md.vloc = BLE_GATTS_VLOC_STACK; // BLE_GATTS_VLOC_STACK is the memory location (stack memory) to store the attributes (characteristic)
	attr_md.rd_auth = 0;
	attr_md.wr_auth = 0;
	attr_md.vlen = 0;

	attr_char_value.p_uuid = &ble_uuid;
	attr_char_value.p_attr_md = &attr_md;
	attr_char_value.init_len = sizeof(uint8_t); // sizeof(uint8_t);
	attr_char_value.init_offs = 0;
	attr_char_value.max_len = BLE_NUS_MAX_TX_CHAR_LEN; // sizeof(uint8_t);

	err_code = sd_ble_gatts_characteristic_add(p_nus->service_handle, &char_md, &attr_char_value, &p_nus->tx_handles);
	if (err_code != NRF_SUCCESS) {
		return err_code;
	}

	return NRF_SUCCESS;
}

// Add the Progress Characteristic.

static uint32_t progress_char_add(ble_nus_t *p_nus, const ble_nus_init_t *p_nus_init)
{
	uint32_t err_code;
	ble_gatts_char_md_t char_md;
	ble_gatts_attr_md_t cccd_md;
	ble_gatts_attr_md_t attr_md;
	ble_gatts_attr_t attr_char_value;
	ble_uuid_t ble_uuid;

	// Initiliaze the structures
	memset(&cccd_md, 0, sizeof(cccd_md));
	memset(&char_md, 0, sizeof(char_md));
	memset(&attr_md, 0, sizeof(attr_md));
	memset(&attr_char_value, 0, sizeof(attr_char_value));

	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);

	// Client Characteristic Configuration Descriptor metadata.
	cccd_md.vloc = BLE_GATTS_VLOC_STACK; // decide where to store the descriptor (the value of the CCCD), and once again we store it in the SoftDevice controlled part of memory (as we did with the characteristic)
	char_md.char_props.read = 1;	     // Enable read
	char_md.char_props.notify = 1;	     // Enable notifications
	char_md.p_char_user_desc = NULL;
	char_md.p_char_pf = NULL;
	char_md.p_user_desc_md = NULL;
	char_md.p_cccd_md = &cccd_md;

	char_md.p_sccd_md = NULL;

	ble_uuid.type = p_nus->uuid_type;
	ble_uuid.uuid = PROGRESS_VALUE_CHAR_UUID;

	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);

	attr_md.read_perm = p_nus_init->progress_char_attr_md.read_perm;
	attr_md.write_perm = p_nus_init->progress_char_attr_md.write_perm;
	attr_md.vloc = BLE_GATTS_VLOC_STACK; // BLE_GATTS_VLOC_STACK is the memory location (stack memory) to store the attributes (characteristic)
	attr_md.rd_auth = 0;
	attr_md.wr_auth = 0;
	attr_md.vlen = 0;

	attr_char_value.p_uuid = &ble_uuid;
	attr_char_value.p_attr_md = &attr_md;
	attr_char_value.init_len = sizeof(uint8_t); // sizeof(uint8_t);
	attr_char_value.init_offs = 0;
	attr_char_value.max_len = sizeof(uint8_t); // sizeof(uint8_t);

	err_code = sd_ble_gatts_characteristic_add(p_nus->service_handle, &char_md, &attr_char_value, &p_nus->progress_handles);
	if (err_code != NRF_SUCCESS) {
		return err_code;
	}

	return NRF_SUCCESS;
}

// Add the Results Characteristic.

static uint32_t results_char_add(ble_nus_t *p_nus, const ble_nus_init_t *p_nus_init)
{
	uint32_t err_code;
	ble_gatts_char_md_t char_md;
	ble_gatts_attr_md_t cccd_md;
	ble_gatts_attr_md_t attr_md;
	ble_gatts_attr_t attr_char_value;
	ble_uuid_t ble_uuid;

	// Initiliaze the structures
	memset(&cccd_md, 0, sizeof(cccd_md));
	memset(&char_md, 0, sizeof(char_md));
	memset(&attr_md, 0, sizeof(attr_md));
	memset(&attr_char_value, 0, sizeof(attr_char_value));

	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);

	// Client Characteristic Configuration Descriptor metadata.
	cccd_md.vloc = BLE_GATTS_VLOC_STACK; // decide where to store the descriptor (the value of the CCCD), and once again we store it in the SoftDevice controlled part of memory (as we did with the characteristic)
	char_md.char_props.read = 1;	     // Enable read
	char_md.char_props.notify = 1;	     // Enable notifications
	char_md.p_char_user_desc = NULL;
	char_md.p_char_pf = NULL;
	char_md.p_user_desc_md = NULL;
	char_md.p_cccd_md = &cccd_md;

	char_md.p_sccd_md = NULL;

	ble_uuid.type = p_nus->uuid_type;
	ble_uuid.uuid = RESULTS_VALUE_CHAR_UUID;

	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);

	attr_md.read_perm = p_nus_init->results_char_attr_md.read_perm;
	attr_md.write_perm = p_nus_init->results_char_attr_md.write_perm;
	attr_md.vloc = BLE_GATTS_VLOC_STACK; // BLE_GATTS_VLOC_STACK is the memory location (stack memory) to store the attributes (characteristic)
	attr_md.rd_auth = 0;
	attr_md.wr_auth = 0;
	attr_md.vlen = 0;

	attr_char_value.p_uuid = &ble_uuid;
	attr_char_value.p_attr_md = &attr_md;
	attr_char_value.init_len = 8; // sizeof(uint8_t);
	attr_char_value.init_offs = 0;
	attr_char_value.max_len = 8; // sizeof(uint8_t);

	err_code = sd_ble_gatts_characteristic_add(p_nus->service_handle, &char_md, &attr_char_value, &p_nus->results_handles);
	if (err_code != NRF_SUCCESS) {
		return err_code;
	}

	return NRF_SUCCESS;
}

// This is where we will implement the notification
uint32_t ble_progress_update(ble_nus_t *p_nus, uint8_t custom_value)
{
	NRF_LOG_INFO("In ble_cus_custom_value_update. \r\n");
	if (p_nus == NULL) {
		return NRF_ERROR_NULL;
	}

	uint32_t err_code = NRF_SUCCESS;
	ble_gatts_value_t gatts_value;
	ble_nus_evt_t evt;

	// Initialize value struct.
	memset(&gatts_value, 0, sizeof(gatts_value));

	gatts_value.len = sizeof(custom_value);
	gatts_value.offset = 0;
	gatts_value.p_value = &custom_value;

	// Update database.
	err_code = sd_ble_gatts_value_set(p_nus->conn_handle,
	    p_nus->progress_handles.value_handle,
	    &gatts_value);
	if (err_code != NRF_SUCCESS) {
		return err_code;
	}

	// Send value if connected and notifying.
	if ((p_nus->conn_handle != BLE_CONN_HANDLE_INVALID)) {
		ble_gatts_hvx_params_t hvx_params;

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

		hvx_params.handle = p_nus->progress_handles.value_handle;
		hvx_params.type = BLE_GATT_HVX_NOTIFICATION;
		hvx_params.offset = gatts_value.offset;
		hvx_params.p_len = &gatts_value.len;
		hvx_params.p_data = gatts_value.p_value;

		err_code = sd_ble_gatts_hvx(p_nus->conn_handle, &hvx_params);
		// NRF_LOG_INFO("sd_ble_gatts_hvx result: %x. \r\n", err_code);
	} else {
		err_code = NRF_ERROR_INVALID_STATE;
		NRF_LOG_INFO("sd_ble_gatts_hvx result: NRF_ERROR_INVALID_STATE. \r\n");
	}
	evt.type = UART_RX_DATA;
	NRF_LOG_INFO("Event type: %d", evt.type);
	p_nus->data_handler(&evt);

	return err_code;
}

uint32_t ble_results_update(ble_nus_t *p_nus, uint8_t *results_value)
{
	NRF_LOG_INFO("In ble_cus_results_value_update. \r\n");
	if (p_nus == NULL) {
		return NRF_ERROR_NULL;
	}

	uint32_t err_code = NRF_SUCCESS;
	ble_gatts_value_t gatts_value;

	// Initialize value struct.
	memset(&gatts_value, 0, sizeof(gatts_value));

	gatts_value.len = sizeof(results_value);
	gatts_value.offset = 0;
	gatts_value.p_value = results_value;

	// Update database.
	err_code = sd_ble_gatts_value_set(p_nus->conn_handle,
	    p_nus->results_handles.value_handle,
	    &gatts_value);
	if (err_code != NRF_SUCCESS) {
		return err_code;
	}

	// Send value if connected and notifying.
	if ((p_nus->conn_handle != BLE_CONN_HANDLE_INVALID)) {
		ble_gatts_hvx_params_t hvx_params;

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

		hvx_params.handle = p_nus->results_handles.value_handle;
		hvx_params.type = BLE_GATT_HVX_NOTIFICATION;
		hvx_params.offset = gatts_value.offset;
		hvx_params.p_len = &gatts_value.len;
		hvx_params.p_data = gatts_value.p_value;

		err_code = sd_ble_gatts_hvx(p_nus->conn_handle, &hvx_params);
		NRF_LOG_INFO("sd_ble_gatts_hvx result: %x. \r\n", err_code);
	} else {
		err_code = NRF_ERROR_INVALID_STATE;
		NRF_LOG_INFO("sd_ble_gatts_hvx result: NRF_ERROR_INVALID_STATE. \r\n");
	}

	return err_code;
}

uint32_t ble_nus_init(ble_nus_t *p_nus, ble_nus_init_t const *p_nus_init)
{
	ret_code_t err_code;
	ble_uuid_t ble_uuid;
	ble_uuid128_t nus_base_uuid = NUS_BASE_UUID;
	ble_add_char_params_t add_char_params;

	VERIFY_PARAM_NOT_NULL(p_nus);
	VERIFY_PARAM_NOT_NULL(p_nus_init);

	// Initialize the service structure.
	p_nus->data_handler = p_nus_init->data_handler;

	/**@snippet [Adding proprietary Service to the SoftDevice] */
	// Add a custom base UUID.
	err_code = sd_ble_uuid_vs_add(&nus_base_uuid, &p_nus->uuid_type);
	VERIFY_SUCCESS(err_code);

	ble_uuid.type = p_nus->uuid_type;
	ble_uuid.uuid = BLE_UUID_NUS_SERVICE;

	// Add the service.
	err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
	    &ble_uuid,
	    &p_nus->service_handle);
	/**@snippet [Adding proprietary Service to the SoftDevice] */
	VERIFY_SUCCESS(err_code);

	err_code = rx_char_add(p_nus, p_nus_init);
	if (err_code != NRF_SUCCESS) {
		return err_code;
	}

	err_code = tx_char_add(p_nus, p_nus_init);
	if (err_code != NRF_SUCCESS) {
		return err_code;
	}

	err_code = progress_char_add(p_nus, p_nus_init);
	if (err_code != NRF_SUCCESS) {
		return err_code;
	}

	err_code = results_char_add(p_nus, p_nus_init);
	if (err_code != NRF_SUCCESS) {
		return err_code;
	}
}

uint32_t ble_nus_data_send(ble_nus_t *p_nus,
    uint8_t *p_data,
    uint16_t *p_length,
    uint16_t conn_handle)
{
	ret_code_t err_code;
	ble_gatts_hvx_params_t hvx_params;
	ble_nus_client_context_t *p_client;

	VERIFY_PARAM_NOT_NULL(p_nus);

	err_code = blcm_link_ctx_get(p_nus->p_link_ctx_storage, conn_handle, (void *)&p_client);
	VERIFY_SUCCESS(err_code);

	if ((conn_handle == BLE_CONN_HANDLE_INVALID) || (p_client == NULL)) {
		return NRF_ERROR_NOT_FOUND;
	}

	if (!p_client->is_notification_enabled) {
		return NRF_ERROR_INVALID_STATE;
	}

	if (*p_length > BLE_NUS_MAX_DATA_LEN) {
		return NRF_ERROR_INVALID_PARAM;
	}

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

	hvx_params.handle = p_nus->tx_handles.value_handle;
	hvx_params.p_data = p_data;
	hvx_params.p_len = p_length;
	hvx_params.type = BLE_GATT_HVX_NOTIFICATION;

	return sd_ble_gatts_hvx(conn_handle, &hvx_params);
}

#endif // NRF_MODULE_ENABLED(BLE_NUS)

[Einar Thorsrud]

I am still not sure where you see the issue though. The UART terminal on your PC, is that observing the UART output of nRF (log output), or is it form NUS? In any case, there is something fishy here:

Your counter is a integer:

static int counter = 0;

And you print it as if it was a string, which is clearly wrong:

NRF_LOG_INFO("CDC ACM unavailable, data received: %s", counter);

Here you should use %d or %i instead of %s (which is for a string). This is just in the log when there is an error though, but it makes me wonder if you have other similar mistakes.

Along that line, I also don't understand your ble_progress_update(). Here you send the integer value (now an uint8) without converting it to ascii. As you take the size of it and handle it as if it was an array (which it is not, and as an uint8 the size is always 1) you are on to something, but it is only half-done. It is expectd that you get garbeled data as you are effectivly sending an uint8 (which is your counter stripped down to 8 bit) which is not a character, and that is all.

First of all, you need to convert your ocunter to a string,. You could do that in your ble_progress_update() or before, that is up to you. Secondly, I don't understand why you use the lower level sd_ble_gatts API for this, as you are using NUS. There are NUS functions for sending a string. Just look at the ble_app_uart sample. Essentially, convert your counter to a string (using for instance snprintf(counter_string, sizeof(counter_string)"%s", counter)), and send it with ble_nus_data_send(). No need to re-implement things that is already there. That is both a wast of time and error prone.

[kleanthise]

I think it is from NUS, for example when i am sending from the nrfconnect application the command 0x01 which i have set as the command for activating this counter, i can see that command on terminal.

I will try and convert the counter to string and run it again and see if that resolves this issue.

Thanks 

[kleanthise]

if (p_evt->type == UART_RX_DATA) {
		ret_code_t ret;
		//memcpy(&counter, p_evt->params.tx_data.p_data, p_evt->params.tx_data.length);
		// uint16_t length = p_evt->params.tx_data.length;

		NRF_LOG_INFO("UART_TX");

		static char buf[sizeof(counter)];
		int j = snprintf(buf, sizeof(buf), "%s", counter);
		uint16_t length = strlen(buf);
		ret = app_usbd_cdc_acm_write(&m_app_cdc_acm, &j, length);

		if (ret != NRF_SUCCESS) {
			NRF_LOG_INFO("CDC ACM unavailable, data received: %d", counter);
		}
	}

I have modified my code inside nus_data_handler . Now some data are passing over to terminal but again are wrong. Have i done the conversion from integer to string correct ?

Thanks
Kle

[Einar Thorsrud]

No, there are a number of issues here. Both what I pointed to before, and then from this snippet. Let's start with this line:

static char buf[sizeof(counter)];

Here you make the buffer sizeof(counter), and counter is an integer, so this is 4. And a string is 0 terminated, so this can hold 3 characters + the nullt ermination. So the largest number you can hav here as ASCII is "999". If that is OK, then it is fine. If not, make the buffer bigger.

Then the next line:

int j = snprintf(buf, sizeof(buf), "%s", counter);

This in itself looks good. Here the j that is returned from snprintf hold the actual length of the string (not including the null termination). It does not hold the string, which is in buf. So it makes no sense to pass the address to j where you should have passed the buffer in this line:

ret = app_usbd_cdc_acm_write(&m_app_cdc_acm, &j, length);

This should instead have been something like this:

ret = app_usbd_cdc_acm_write(&m_app_cdc_acm, buff, j);

(assuming you don't want to include the null termination. If you want it, it would be j+1 as the last parameter.

These are generic C programming issues (with handling pointers, arrays and C strings). So I suggest you look a bit into that before continuing with this.

[kleanthise]

Ok now makes more sense. thanks a lot for clarifying this.

The value of counter that should be incrementing from 1,2,3,4,5 is still not shown in the terminal. Instead i am looking at some values that i do not understand from where they are coming.

shouldnt the command int j = sprintf(buf, sizeof(buf), "s%" , counter) be printed on the terminal ? or maybe i am missing something ?