How do I implement an address filter?

[panda_noob_2000]

I am very new to BLE development, and am building my application on top of the ble_central\ble_app_uart_c example.

I have this tag defined at the start, with the other global variable definitions.

#define NRF_BLE_SCAN_ADDR_FILTER 0x02

This is the function where I am initializing the module: 

/**
 * @brief Parameters used when scanning.
 */
static const ble_gap_scan_params_t m_scan_params =
{
    .active   = 1,
    .interval = SCAN_INTERVAL,
    .window   = SCAN_WINDOW,
    .timeout  = SCAN_TIMEOUT,
    #if (NRF_SD_BLE_API_VERSION == 2)
        .selective   = 0,
        .p_whitelist = NULL,
    #endif
    #if (NRF_SD_BLE_API_VERSION == 3)
        .use_whitelist = 0,
    #endif
};

 

I am calling the module (or setting the filter, unsure of the terminology) here in the scan_start() function:

/**
 * @brief Parameters used when scanning.
 */
static const ble_gap_scan_params_t m_scan_params =
{
    .active   = 1,
    .interval = SCAN_INTERVAL,
    .window   = SCAN_WINDOW,
    .timeout  = SCAN_TIMEOUT,
    #if (NRF_SD_BLE_API_VERSION == 2)
        .selective   = 0,
        .p_whitelist = NULL,
    #endif
    #if (NRF_SD_BLE_API_VERSION == 3)
        .use_whitelist = 0,
    #endif
};

The scan_start() function is called in main(). I have not yet tested this implementation as it is unfinished.

My questions around this are:

1. Where do I set the address I want to filter for? It merely advertises and I can't connect to it.
2. Once the address is set, is this implementation correct?

Thank you!

[Karl Ylvisaker]

Hello again, Maria

Looking into the source code of the nrf_ble_scan_filters_set function I see that NRF_ERROR_INVALID_PARAM is returned if the defined number for that filter type.
Have you changed your NRF_BLE_SCAN_ADDRESS_CNT to 1, in your sdk_config?

Best regards,
Karl

[panda_noob_2000]

Hello,

NRF_BLE_SCAN_ADDRESS_CNT was set to 0. I tried to set it to 1 in both the text editor and the configuration wizard, and both times I got this error when I tried to save the file: 

Thanks,

Maria

[Karl Ylvisaker]

Hello Maria,

panda_noob_2000 said:

NRF_BLE_SCAN_ADDRESS_CNT was set to 0. I tried to set it to 1 in both the text editor and the configuration wizard, and both times I got this error when I tried to save the file

That's very strange, I've never encountered this issue in Keil before.
The Keil documentation says that this error indicates that the memory is not available to write.
Could you check where you are storing your file, and that it is not already open in another program?
Are you able to write any of the other defines in the sdk_config, or to change it at all?

If the problem persists I recommend that you open a separate ticket for this, since this is diverging from the original scanning issue. This helps to keep the forum tidy and easy to navigate for other users.

Best regards,
Karl

[panda_noob_2000]

Hi Karl,

Hope you are well.

Regarding the write error - I had the file open in another editor. Closing the second editor and restarting Keil IDE resolved the issue for me. Thanks for the idea.

The address filter is now running without errors, but it is not picking up any advertising packets. My thought is that I have entered the address or address type incorrectly.

I am determining whether or not an advertising packet is picked up by putting print statement in the scan callback function here:

I implemented the NRF BLE sniffer and the output is shown below. The highlighted line is from the advertising sensor; I know this as the three bytes are part of the address of the specific device.

This is how I have entered the address into Keil IDE:

Do you have any ideas regarding what could be going on? Thanks for your help!

Best, 

Maria

[Simonr]

Karl is out of office for the time being. This case is continued in https://devzone.nordicsemi.com/f/nordic-q-a/78010/address-filter-not-working 

Best regards,

Simon