BLE number of pakets NRF52832

[marsss]

Hi everybody,

I have a question about the number of data pakets which I can send with the BLE. Every data paket has a range of 20 Byte.

Now I want to send about 55 of these data pakets. But I only can send 10 then it works without problems. When I want to send more than 10 pakets, my device is sending 10 and after that, the BLE is crashing. 

What is used:. Nrf52832 module, ble_nus.c  

Does anybody know, why I can only send, in every case I tried, 10 pakets. Maybe it is defined anywhere and I don't know where.

Thanks a lot 

Marius

[Sigurd]

Hi,

The internal SoftDevice buffer is probably full. Do you get any error-codes printed in debug configuration  ?

Try increasing NRF_SDH_BLE_GAP_EVENT_LENGTH in sdk_config.h to e.g. 300

[marsss]

That could be. No, I don't get an other error code in the debug mode. 

I'll try with your tip and give feedback

Thanks a lot

[marsss]

I tried to Change the NRF_SDH_BLE_GAP_EVENT_LENGTH like you said. But then I get the error 4 which says not enough memory? 

[Sigurd]

You need to adjust the allocated RAM to the SoftDevice. In Segger Embedded Studio you can adjust it here:

[marsss]

Yes, thank you  

Do you know, how big I can big I can do the RAM size? - Or does it depends on the Code size?

[Sigurd]

How much RAM the SoftDevice needs depends on how you configure the SoftDevice. Configuring e.g. more characteristics and services, the SoftDevice will require more RAM. The exact number is returned by the function sd_ble_enable(), and if it needs to be adjusted, it’s printed in the nrf_sdh_ble_enable() function in nrf_sdh_ble.c

Snippet:

ret_code_t nrf_sdh_ble_enable(uint32_t * const p_app_ram_start)
{
    // Start of RAM, obtained from linker symbol.
    uint32_t const app_ram_start_link = *p_app_ram_start;

    ret_code_t ret_code = sd_ble_enable(p_app_ram_start);
    if (*p_app_ram_start > app_ram_start_link)
    {
        NRF_LOG_WARNING("Insufficient RAM allocated for the SoftDevice.");

        NRF_LOG_WARNING("Change the RAM start location from 0x%x to 0x%x.",
                        app_ram_start_link, *p_app_ram_start);
        NRF_LOG_WARNING("Maximum RAM size for application is 0x%x.",
                        ram_end_address_get() - (*p_app_ram_start));
    }
    else
    {
        NRF_LOG_DEBUG("RAM starts at 0x%x", app_ram_start_link);
        if (*p_app_ram_start != app_ram_start_link)
        {
            NRF_LOG_DEBUG("RAM start location can be adjusted to 0x%x.", *p_app_ram_start);

            NRF_LOG_DEBUG("RAM size for application can be adjusted to 0x%x.",
                          ram_end_address_get() - (*p_app_ram_start));
        }
    }

    if (ret_code == NRF_SUCCESS)
    {
        m_stack_is_enabled = true;
    }
    else
    {
        NRF_LOG_ERROR("sd_ble_enable() returned %s.", nrf_strerror_get(ret_code));
    }

    return ret_code;
}

[marsss]

Ok, thanks a lot. this works!