I've been documenting this issue and asking questions here:
Intermittent device reset in modified ble_app_beacon example
Since I need to post a proprietary schematic, I made this private post to continue.
This project is a stripped down version of a product under development. It depends upon being able to change the contents of the advertising data whenever the board (a sensor) detects a new state. The code as shown generally works but eventually the device resets. This could happen after running for a few minutes or a few days or anywhere in between.
I've removed the schematic and am now making this post public.
At this point I am gaining confidence that the programmer was damaging the coin cells with the reverse current. I've appealed to Nordic to document this in the DK user guide and am converting this post to public in case they don't.
We did not find any issues with the schematic.
You can find a list over different reset sources here. https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/power.html?cp=2_1_0_17_5#unique_213661016
1) Do you see the reset issue if you power the devices with external supply, instead of using coin cell battery?
2) Have you measured the ripple on VDD?
3) Do you have this issue on all boards? or only some?
4) If you don't have this issue on all boards; then if you take the coin cell from a "good" device, and use it on a "bad" device, do you still see the issue on the "bad" device ?
Also note that a step increase in supply voltage of 300 mV or more, with rise time of 300 ms or less, within the valid supply range, may result in a system reset.
To keep track of how often the board rests, you can try this modified beacon example. You will need to add nrf_nvmc.c (found in SDK_15_2_folder/modules/nrfx / hal) to the ble_app_beacon example to test it. The major value keeps track of how many times the boards is reset, and the minor value shows the value of the RESETREAS register. You can use e.g. nRF Connect for mobile to show the major and minor values.
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* @defgroup ble_sdk_app_beacon_main main.c
* @ingroup ble_sdk_app_beacon
* @brief Beacon Transmitter Sample Application main file.
* This file contains the source code for an Beacon transmitter sample application.
#define APP_BLE_CONN_CFG_TAG 1 /**< A tag identifying the SoftDevice BLE configuration. */
#define NON_CONNECTABLE_ADV_INTERVAL MSEC_TO_UNITS(100, UNIT_0_625_MS) /**< The advertising interval for non-connectable advertisement (100 ms). This value can vary between 100ms to 10.24s). */
#define APP_BEACON_INFO_LENGTH 0x17 /**< Total length of information advertised by the Beacon. */
#define APP_ADV_DATA_LENGTH 0x15 /**< Length of manufacturer specific data in the advertisement. */
#define APP_DEVICE_TYPE 0x02 /**< 0x02 refers to Beacon. */
#define APP_MEASURED_RSSI 0xC3 /**< The Beacon's measured RSSI at 1 meter distance in dBm. */
#define APP_COMPANY_IDENTIFIER 0x0059 /**< Company identifier for Nordic Semiconductor ASA. as per www.bluetooth.org. */
#define APP_MAJOR_VALUE 0x01, 0x02 /**< Major value used to identify Beacons. */
#define APP_MINOR_VALUE 0x03, 0x04 /**< Minor value used to identify Beacons. */
#define APP_BEACON_UUID 0x01, 0x12, 0x23, 0x34, \
0x45, 0x56, 0x67, 0x78, \
0x89, 0x9a, 0xab, 0xbc, \
0xcd, 0xde, 0xef, 0xf0 /**< Proprietary UUID for Beacon. */
#define DEAD_BEEF 0xDEADBEEF /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */
#define MAJ_VAL_OFFSET_IN_BEACON_INFO 18 /**< Position of the MSB of the Major Value in m_beacon_info array. */
#define UICR_ADDRESS 0x10001080 /**< Address of the UICR register used by this example. The major and minor versions to be encoded into the advertising data will be picked up from this location. */
static ble_gap_adv_params_t m_adv_params; /**< Parameters to be passed to the stack when starting advertising. */
static uint8_t m_adv_handle = BLE_GAP_ADV_SET_HANDLE_NOT_SET; /**< Advertising handle used to identify an advertising set. */
static uint8_t m_enc_advdata[BLE_GAP_ADV_SET_DATA_SIZE_MAX]; /**< Buffer for storing an encoded advertising set. */
#define MY_ADDRESS 0x32000
static uint32_t number_of_resets;
static uint32_t reset_reason;
/**@brief Struct that contains pointers to the encoded advertising data. */
static ble_gap_adv_data_t m_adv_data =
.p_data = m_enc_advdata,
.len = BLE_GAP_ADV_SET_DATA_SIZE_MAX
.p_data = NULL,
.len = 0
static uint8_t m_beacon_info[APP_BEACON_INFO_LENGTH] = /**< Information advertised by the Beacon. */
APP_DEVICE_TYPE, // Manufacturer specific information. Specifies the device type in this
APP_ADV_DATA_LENGTH, // Manufacturer specific information. Specifies the length of the
// manufacturer specific data in this implementation.
APP_BEACON_UUID, // 128 bit UUID value.
APP_MAJOR_VALUE, // Major arbitrary value that can be used to distinguish between Beacons.
APP_MINOR_VALUE, // Minor arbitrary value that can be used to distinguish between Beacons.
APP_MEASURED_RSSI // Manufacturer specific information. The Beacon's measured TX power in
// this implementation.
/**@brief Callback function for asserts in the SoftDevice.
* @details This function will be called in case of an assert in the SoftDevice.
* @warning This handler is an example only and does not fit a final product. You need to analyze
* how your product is supposed to react in case of Assert.
* @warning On assert from the SoftDevice, the system can only recover on reset.
* @param[in] line_num Line number of the failing ASSERT call.
* @param[in] file_name File name of the failing ASSERT call.
void assert_nrf_callback(uint16_t line_num, const uint8_t * p_file_name)
app_error_handler(DEAD_BEEF, line_num, p_file_name);
/**@brief Function for initializing the Advertising functionality.
* @details Encodes the required advertising data and passes it to the stack.
* Also builds a structure to be passed to the stack when starting advertising.
static void advertising_init(void)
uint8_t flags = BLE_GAP_ADV_FLAG_BR_EDR_NOT_SUPPORTED;
manuf_specific_data.company_identifier = APP_COMPANY_IDENTIFIER;
// If USE_UICR_FOR_MAJ_MIN_VALUES is defined, the major and minor values will be read from the
// UICR instead of using the default values. The major and minor values obtained from the UICR
// are encoded into advertising data in big endian order (MSB First).
// To set the UICR used by this example to a desired value, write to the address 0x10001080
// using the nrfjprog tool. The command to be used is as follows.
// nrfjprog --snr <Segger-chip-Serial-Number> --memwr 0x10001080 --val <your major/minor value>
// For example, for a major value and minor value of 0xabcd and 0x0102 respectively, the
// the following command should be used.
// nrfjprog --snr <Segger-chip-Serial-Number> --memwr 0x10001080 --val 0xabcd0102
uint16_t major_value = ((*(uint32_t *)UICR_ADDRESS) & 0xFFFF0000) >> 16;
uint16_t minor_value = ((*(uint32_t *)UICR_ADDRESS) & 0x0000FFFF);
uint8_t index = MAJ_VAL_OFFSET_IN_BEACON_INFO;
m_beacon_info[index++] = MSB_16(major_value);
m_beacon_info[index++] = LSB_16(major_value);
m_beacon_info[index++] = MSB_16(minor_value);
m_beacon_info[index++] = LSB_16(minor_value);
m_beacon_info = 0x00;
m_beacon_info = number_of_resets;
m_beacon_info = 0x00;
m_beacon_info = reset_reason;
manuf_specific_data.data.p_data = (uint8_t *) m_beacon_info;
manuf_specific_data.data.size = APP_BEACON_INFO_LENGTH;
// Build and set advertising data.
memset(&advdata, 0, sizeof(advdata));
advdata.name_type = BLE_ADVDATA_NO_NAME;
advdata.flags = flags;
advdata.p_manuf_specific_data = &manuf_specific_data;
// Initialize advertising parameters (used when starting advertising).
memset(&m_adv_params, 0, sizeof(m_adv_params));
m_adv_params.properties.type = BLE_GAP_ADV_TYPE_NONCONNECTABLE_NONSCANNABLE_UNDIRECTED;
m_adv_params.p_peer_addr = NULL; // Undirected advertisement.
m_adv_params.filter_policy = BLE_GAP_ADV_FP_ANY;
m_adv_params.interval = NON_CONNECTABLE_ADV_INTERVAL;
m_adv_params.duration = 0; // Never time out.
err_code = ble_advdata_encode(&advdata, m_adv_data.adv_data.p_data, &m_adv_data.adv_data.len);
err_code = sd_ble_gap_adv_set_configure(&m_adv_handle, &m_adv_data, &m_adv_params);
/**@brief Function for starting advertising.
static void advertising_start(void)
err_code = sd_ble_gap_adv_start(m_adv_handle, APP_BLE_CONN_CFG_TAG);
err_code = bsp_indication_set(BSP_INDICATE_ADVERTISING);
/**@brief Function for initializing the BLE stack.
* @details Initializes the SoftDevice and the BLE event interrupt.
static void ble_stack_init(void)
err_code = nrf_sdh_enable_request();
// 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);
// Enable BLE stack.
err_code = nrf_sdh_ble_enable(&ram_start);
/**@brief Function for initializing logging. */
static void log_init(void)
ret_code_t err_code = NRF_LOG_INIT(NULL);
/**@brief Function for initializing LEDs. */
static void leds_init(void)
ret_code_t err_code = bsp_init(BSP_INIT_LEDS, NULL);
/**@brief Function for initializing timers. */
static void timers_init(void)
ret_code_t err_code = app_timer_init();
/**@brief Function for initializing power management.
static void power_management_init(void)
err_code = nrf_pwr_mgmt_init();
/**@brief Function for handling the idle state (main loop).
* @details If there is no pending log operation, then sleep until next the next event occurs.
static void idle_state_handle(void)
if (NRF_LOG_PROCESS() == false)
* @brief Function for application main entry.
number_of_resets = *(uint32_t *)MY_ADDRESS;
if(number_of_resets == 0xffffffff)
number_of_resets = 0;
reset_reason = NRF_POWER->RESETREAS;
// Start execution.
NRF_LOG_INFO("Beacon example started.");
// Enter main loop.
for (;; )