HardFault when sending UART data over NUS

[AndreaFont]

Hi all,

As written above, as soon as I try to send an array of 8 bytes(8,255,0,1,64,64,0,1) onto the NUS the ble_nus_data_send and the consecutive sd_ble_gatts_hvx() trigger an hardfault which I am struggling to understand. 

In the call: 

ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);

data_array[BLE_NUS_MAX_DATA_LEN(244)] = [8,255,0,1,64,64,0,1, 0 ,0, ..0]

length = 8

m_conn_handle = 0

m_nus:

    uint32_t           err_code;

    ble_nus_init_t     nus_init;

    nrf_ble_qwr_init_t qwr_init = {0};

    // Initialize Queued Write Module.

    qwr_init.error_handler = nrf_qwr_error_handler;

    err_code = nrf_ble_qwr_init(&m_qwr, &qwr_init);

    APP_ERROR_CHECK(err_code);

    // Initialize NUS.

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

    nus_init.data_handler = nus_data_handler;

    err_code = ble_nus_init(&m_nus, &nus_init);

    APP_ERROR_CHECK(err_code);

Please see below attached the stack trace.

SDK: 17.1.0
SD: S112 7.2.0
Related flags: SD_BLE_API_VERSION=7



Registers:

Thank you!!!

[AndreaFont]

As I decreased the UART interrupt priority from MID to LOWEST the hardfault disappeared. Any clue why that happens?

[Sigurd]

AndreaFont said:

As I decreased the UART interrupt priority from MID to LOWEST the hardfault disappeared. Any clue why that happens?

You can only call softdevice api from application interrupt priority 5 and lower:

infocenter.nordicsemi.com/.../exception_mgmt_sd.html

[AndreaFont]

That explains! Thank you!