APP_ERROR_CHECK outside main while(1) loop

[KV]

I want to check if some errors happened during the initialization before entering while(1) loop in the main. I am using nrf_CLI in my application (SDK 14.2.0 and S140 on nRF52840).

So my main function looks like

void main( void )
{    
    sys_hw_init();

    log_init();

    cli_init();
            
    cli_start();
                
    err = System_Init();
    APP_ERROR_CHECK(err);
   

    NRF_LOG_INFO("Starting peripheral device...");
        
    while(1)
    {
        cli_process();
        
        if (NRF_LOG_PROCESS() == false)
        {
            wait_for_event();
        }
    }
}

When I use APP_ERROR_CHECK outside the main loop and there is an error, I don't see anything printed on the serial terminal (err is non-zero and not equal to NRF_SUCCESS). But if run time error occurs after application enters the main loop, then I see APP_ERROR_CHECK function normally without issues.

What could be wrong in the usage? It gets stuck inside the macro NRF_LOG_ERROR in the app_error_fault_handler routine , case NRF_FAULT_ID_SDK_ASSERT.

[KV]

I moved the cli_start to just above while(1) loop and then it starts to work without issues now. See below:

void main( void )
{    
    sys_hw_init();

    log_init();

    cli_init();

    err = System_Init();
    APP_ERROR_CHECK(err);

    NRF_LOG_INFO("Starting peripheral device...");
    
    cli_start();

    while(1)
    {
        cli_process();

        if (NRF_LOG_PROCESS() == false)
        {
            wait_for_event();
        }
    }
}

[MartinBL]

1. What kind of backends do you use for logging and CLI?
2. Are you checking return codes in cli_init() and cli_start()?

[KV]

Yes. I am checking for errors inside cli_init and cli_start. There are no errors and it returns from those two functions. I am using UART as backend.

void CLI_Init(void)
{
    nrf_drv_uart_config_t uart_config = NRF_DRV_UART_DEFAULT_CONFIG;
    uart_config.pseltxd = TX_PIN_NUMBER;
    uart_config.pselrxd = RX_PIN_NUMBER;
    uart_config.hwfc    = NRF_UART_HWFC_DISABLED;

    ret_code_t err_code = nrf_cli_init(&m_cli_uart, &uart_config, true, true, NRF_LOG_SEVERITY_INFO);
    APP_ERROR_CHECK(err_code);
    
}
 
void CLI_Start(void)
{    
    ret_code_t err_code =  nrf_cli_start(&m_cli_uart);
    APP_ERROR_CHECK(err_code);    
}

[MartinBL]

The nrf_cli_start() function requires that the app_timer library has been initialized. Do you do this in sys_hw_init() or System_Init()? If you do it in System_Init() it would make sense that it works with cli_start() after, but not before. It wouldn't make sense that nrf_cli_start() don't return an error though.

[KV]

The app_timer_init is called inside the sys_hw_init. The nrf_cli_start is checking only for UART initialization. Is that correct? I think I should try this similar sequence in ble_att_mtu_throughput example which uses CLI and see if I can reproduce the same issue.