Hi,
I have developed firmware on nRF52840 as a peripheral.
Now I have to develop firmware on nRF52832(beacon) as central which scans the first device and connects and sends data on characteristics. How can I do this? I have checked central_blinky example and am able to connect but how can I sned data?
Thanks!
Hi,
For central, you can find example ble_app_uart_c with the NUS service. For comparison, the peripheral associated example is ble_app_uart.
ble_nus_c_string_send is the function that sends the data in ble_nus_c.
A beacon as a central isn't a conventional method. Take care to the consumption during scan.
Victor
This is exactly what is done by the ble_app_uart_c example. It checks the name of the peripheral in the scan report and if it matches "Nordic_Blinky" it sends a connection request. Try flashing the peripheral with the unmodified ble_app_uart example and see if it connects.
hi @Jared
I have uploaded the mentioned project but it's not scanning and I am also unable to see how central is scanning by name in the main code.
C:\Nordic2\SDK\nRF5SDK1702d674dde\nRF5_SDK_17.0.2_d674dde\examples\ble_central\ble_app_uart_c
/**
* Copyright (c) 2016 - 2020, 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.
*
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* 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 <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"
#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 1 /**< Echo the UART data that is received over the Nordic UART Service (NUS) back to the sender. */
BLE_NUS_C_DEF(m_ble_nus_c); /**< BLE Nordic UART Service (NUS) client instance. */
NRF_BLE_GATT_DEF(m_gatt); /**< GATT module instance. */
BLE_DB_DISCOVERY_DEF(m_db_disc); /**< 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. */
/**@brief NUS UUID. */
static ble_uuid_t const m_nus_uuid =
{
.uuid = BLE_UUID_NUS_SERVICE,
.type = NUS_SERVICE_UUID_TYPE
};
/**@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);
}
/**@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);
}
/**@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);
} break;
case NRF_BLE_SCAN_EVT_CONNECTED:
{
ble_gap_evt_connected_t const * p_connected =
p_scan_evt->params.connected.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]
);
} break;
case NRF_BLE_SCAN_EVT_SCAN_TIMEOUT:
{
NRF_LOG_INFO("Scan timed out.");
scan_start();
} break;
default:
break;
}
}
/**@brief Function for initializing the scanning and setting the filters.
*/
static void scan_init(void)
{
ret_code_t err_code;
nrf_ble_scan_init_t init_scan;
memset(&init_scan, 0, sizeof(init_scan));
init_scan.connect_if_match = true;
init_scan.conn_cfg_tag = APP_BLE_CONN_CFG_TAG;
err_code = nrf_ble_scan_init(&m_scan, &init_scan, scan_evt_handler);
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);
}
/**@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)
{
ret_code_t ret_val;
NRF_LOG_DEBUG("Receiving data.");
NRF_LOG_HEXDUMP_DEBUG(p_data, 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 (p_data[data_len-1] == '\r')
{
while (app_uart_put('\n') == 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)
{
static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
static uint16_t index = 0;
uint32_t ret_val;
switch (p_event->evt_type)
{
/**@snippet [Handling data from UART] */
case APP_UART_DATA_READY:
UNUSED_VARIABLE(app_uart_get(&data_array[index]));
index++;
if ((data_array[index - 1] == '\n') ||
(data_array[index - 1] == '\r') ||
(index >= (m_ble_nus_max_data_len)))
{
NRF_LOG_DEBUG("Ready to send data over BLE NUS");
NRF_LOG_HEXDUMP_DEBUG(data_array, index);
do
{
ret_val = ble_nus_c_string_send(&m_ble_nus_c, data_array, index);
if ( (ret_val != NRF_ERROR_INVALID_STATE) && (ret_val != NRF_ERROR_RESOURCES) )
{
APP_ERROR_CHECK(ret_val);
}
} while (ret_val == NRF_ERROR_RESOURCES);
index = 0;
}
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:
ble_nus_chars_received_uart_print(p_ble_nus_evt->p_data, p_ble_nus_evt->data_len);
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:
err_code = ble_nus_c_handles_assign(&m_ble_nus_c, p_ble_evt->evt.gap_evt.conn_handle, NULL);
APP_ERROR_CHECK(err_code);
err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
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_ble_evt->evt.gap_evt.conn_handle);
APP_ERROR_CHECK(err_code);
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);
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.");
}
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 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);
}
/**@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;
err_code = ble_nus_c_init(&m_ble_nus_c, &init);
APP_ERROR_CHECK(err_code);
}
/**@brief Function for initializing buttons and leds. */
static void buttons_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();
}
}
int main(void)
{
// Initialize.
log_init();
timer_init();
uart_init();
buttons_leds_init();
db_discovery_init();
power_management_init();
ble_stack_init();
gatt_init();
nus_c_init();
scan_init();
// Start execution.
printf("BLE UART central example started.\r\n");
NRF_LOG_INFO("BLE UART central example started.");
scan_start();
// Enter main loop.
for (;;)
{
idle_state_handle();
}
}
However I have checked ble_app_blinky_c which scans and connects with the given device name.. can I use this example code and send and receive data with the peripheral device?