SOFTDEVICE: INVALID MEMORY ACCESS and NRF_FAULT_ID_APP_MEMACC

[Taylor]

Hi,

When  I download the example of "ble_app_uart"(SDK17.0.2  S132) in nRF52832,mty board is working as normal. But when I add RNG in main, the RTT Viewer just logging SOFTDEVICE: INVALID MEMORY ACCESS.

Here is my main code:

int main(void)
{
    bool erase_bonds;
		uint8_t random_value;
    // Initialize.
    uart_init();
    log_init();
    timers_init();
//    buttons_leds_init(&erase_bonds);
    power_management_init();
    ble_stack_init();
    gap_params_init();
    gatt_init();
    services_init();
    advertising_init();
    conn_params_init();

    // Start execution.
    printf("\r\nUART started.\r\n");
    NRF_LOG_INFO("Debug logging for UART over RTT started.");
    advertising_start();

		NRF_RNG->CONFIG=1;
		NRF_RNG->TASKS_START=1;
		NRF_RNG->EVENTS_VALRDY=0;
		while(NRF_RNG->EVENTS_VALRDY==0){}
		random_value=NRF_RNG->VALUE;
		NRF_RNG->TASKS_STOP=1;
		NRF_RNG->INTENCLR=0;               
		NRF_RNG->CONFIG=0; 
    // Enter main loop.
    for (;;)
    {
        idle_state_handle();
    }
}

[Jared]

Hi,

You need to use the Softdevice API when accessing the RNG peripheral when the Softdevice is enabled. 

See more about what resources the Softdevice use here.

regards

Jared 

[Taylor]

I have used normally with S112 on nRF52810. But RNG and TEMP is "Restricted" in S112 . I guess if I used like that will occur an unpredictable error, right?

BTW, could you please show an example about how to use SD API of RNG or TEMP?

[Jared]

It's pretty straightforward, just call the function and it will return with the computed value. For example, if you want to get know the temperature, then you call sd_temp_get(), and it will return with a uint32_t representing the die temperature in 0.25 Celsius. Something like this: 

uint32_t temp;

temp = sd_temp_get();

temp = temp * 0.25;

NRF_LOG_INFO("Temperature of the Die is: %d",temp);

regards

Jared 

[Taylor]

Thanks！

I have found the sd_temp_get(int32_t * p_temp) in nrf_soc.h file, so I need to use like this:

int32_t random_value;
		
sd_temp_get(&random_value);

random_value = random_value*0.24;

NRF_LOG_INFO("Temp: %d",random_value);

 

But I cant find the API to get RNG.

[Jared]

The Softdevice offers limited options when using the RNG peripheral with SD enabled. See the functions that start with sd_rand..

regards

Jared