Address Filter not working

RE: Address Filter not working

panda_noob_2000 — Mon, 23 Aug 2021 12:22:59 GMT

Hello,

this case can be closed. Thank you.

RE: Address Filter not working

Simonr — Mon, 16 Aug 2021 08:56:13 GMT

Hi Maria

Very glad to hear that you were able to solve it by adding a short name filter. As far as I know there haven't been issues like this with address filtering before, and it's hard to say what might have caused this without looking at your project, but I'll report this suspicious behavior internally.

Let me know if this case can be closed.

Best regards,

Simon

RE: Address Filter not working

panda_noob_2000 — Sat, 14 Aug 2021 07:22:58 GMT

Hello,

I got the help of a very skilled BLE engineer, and he was able to solve the issue. We dropped the address filter and implemented a short name filter instead. So we never got the address filter working, but we were able to pick up the sensor by implementing a short name filter instead.

In ble_advdata.c, in the function ble_advdata_short_name_find() he changed line 731 from a less than sign to a less than or equal to sign. This solved the issue. I have attached a screenshot of the fixed function below.

I am curious as to whether or not this is a bug with the sdk - I am using version 17.02.

Thank you,

Maria

RE: Address Filter not working

Simonr — Fri, 13 Aug 2021 07:19:41 GMT

Okay, thank you for confirming. I'm running out of ideas. Would it be possible for you to upload the main.c files for the advertiser and scanning device so I can get a better look at the entirety of your project.

Best regards,

Simon

RE: Address Filter not working

panda_noob_2000 — Wed, 11 Aug 2021 20:34:46 GMT

Hello,

I have attached my code if it would help to take a look. I have adapted the ble_app_uart.c example from the ble_central examples folder.

Thanks,

Maria

RE: Address Filter not working

panda_noob_2000 — Wed, 11 Aug 2021 07:23:06 GMT

Hello,

Thank you for your reply - the value of BLE_GAP_ADDR_LEN is 6 which matches the length of the address I am searching for.

No other filters are enabled.

Thanks,

Maria

RE: Address Filter not working

Simonr — Tue, 10 Aug 2021 08:14:08 GMT

Okay, thank you for the update. Please check out the find_peer_addr() function in nrf_ble_scan.c and make sure that the address you're searching for is corresponding in length to BLE_GAP_ADDR_LEN. Are you also sure that you haven't enabled or are using any other filters that might interfere with the ADDR_FILTER. Here's a list of the possible filters:

/**@defgroup NRF_BLE_SCAN_FILTER_MODE Filter modes
 * @{ */
#define NRF_BLE_SCAN_NAME_FILTER       (0x01) /**< Filters the device name. */
#define NRF_BLE_SCAN_ADDR_FILTER       (0x02) /**< Filters the device address. */
#define NRF_BLE_SCAN_UUID_FILTER       (0x04) /**< Filters the UUID. */
#define NRF_BLE_SCAN_APPEARANCE_FILTER (0x08) /**< Filters the appearance. */
#define NRF_BLE_SCAN_SHORT_NAME_FILTER (0x10) /**< Filters the device short name. */
#define NRF_BLE_SCAN_ALL_FILTER        (0x1F) /**< Uses the combination of all filters. */
/* @} */

RE: Address Filter not working

panda_noob_2000 — Fri, 06 Aug 2021 16:56:40 GMT

Hello,

NRF_BLE_SCAN_ADDRESS_CNT is set to 1 in my sdk_config.h file.

To confirm, yes, the issue is that the EVT_FILTER_MATCH function is not being triggered for whatever reason.

Thanks,

Maria

RE: Address Filter not working

Simonr — Fri, 06 Aug 2021 09:50:14 GMT

What is the

NRF_BLE_SCAN_ADDRESS_CNT define set as in your central's sdk_config.h file? Just to makre sure, the issue is that the "Door Sensor Found" message is not printed as you say in your initial question, right? So the EVT_FILTER_MATCH event is not triggered for some reason even though the address filter should match.

Best regards,

Simon

RE: Address Filter not working

panda_noob_2000 — Fri, 06 Aug 2021 08:53:57 GMT

Hello,

The address was flipped as I read somewhere to input the address LSB first. Regardless, I changed the ble_gap_addr_t() function to the below, and this had no effect on the output. The iSensor is still not being recongized by the application.

Here are the relevant parts of the scan_evt_handler function:

I am judging whether or not the scanner has picked up the iSensor by whether or not line 171 is printed.

Thanks,

Maria

RE: Address Filter not working

Simonr — Thu, 05 Aug 2021 09:32:40 GMT

Okay, sorry for the misunderstanding. Is there any reason that the address is flipped in your ble_gap_addr_t() function compared to what the iSensor is advertising as? In nRFConnect it seems to be backwards, where each byte is flipped. So if your central's filter is looking for the flipped address compared to what is actually advertised that might explain why it's not able to match the addresses.

Best regards,

Simon

RE: Address Filter not working

panda_noob_2000 — Wed, 04 Aug 2021 22:55:00 GMT

Hello,

Apologies for being unclear; the scanning library recognizes all 6 bytes, I was just printing the first 3. When I print the full 6 bytes it matches the address of the iBeacon door sensor.

I used the nrfSniffer firmware with the nrfConnect application to get the complete address and payload. You can see the full address in the image below under iSensor, and you can see the full payload below under ManufacturerSpecificData. Let me know if you have any more thoughts.

Thanks,

Maria

RE: Address Filter not working

Simonr — Wed, 04 Aug 2021 10:17:09 GMT

Can you confirm whether or not the beacon actually advertises the full address, and not just these three bytes? It could be that the iBeacon tries to advertise more than 31 bytes, and therefore some of these address bytes are cut out of the advertisements, causing only 3 of them to be advertised, and would explain why the scanner can't confirm the address.

Best regards,

Simon

RE: Address Filter not working

panda_noob_2000 — Wed, 04 Aug 2021 06:29:21 GMT

Hello,

Thank you - I changed the extended bit to false and now it is running with no errors! However, the scanning module is still not recognizing my iBeacon.

I made some changes to the scan_evt_handler() function and it now looks like this:

In summary, if it sees an advertisement with an address that does not match IM21_ADDRESS, it prints the address it saw. If it sees an advertisement that matches the IM21_ADDRESS, it prints a "Door Sensor Found" message. As the door sensor iBeacon advertises, I see it's address being printed, meaning that the scanning module sees the advertisement, but it appears that the address doesn't match.

This is what is printed (the correct first three bytes of the address): 6bc651

This is what the address is set as:

I don't know what is going on - is the peer address different from the direct address? How can I get the address filter to recognize the address? I checked to make sure that the address type was correct.

Best,

Maria

RE: Address Filter not working

Simonr — Tue, 03 Aug 2021 10:57:09 GMT

Hi Maria

Thank you.

nrf_ble_scan_start() returning error 9 means that there is an invalid length somewhere in this function. Likely returned from the sd_ble_gap_scan_start() function which would indicate that the provided buffer length is invalid. What have you set the buffer length to? The scan buffer length for an advertising set should be 31 bytes. If you set the scan param extended bit to 1, a scan buffer length of 255 is allowed.

Best regards,

Simon

RE: Address Filter not working

panda_noob_2000 — Tue, 03 Aug 2021 00:48:00 GMT

To answer your two questions: I am sure the address set matches the advertising device and I am not sure it starts scanning at all.

In the time since posting this inquiry I have done some debugging, made some modifications, and the application is currently crashing at nrf_ble_scan_start(&m_scan), which is returning 9. I do not know what an error code of 9 means.

I will re attach all the screenshots of my code in case I modified code that was screenshotted above. All these modifications were made to the ble_central/ble_app_uart_c example in the SDK version 17 with soft device 132.

Declaration of advertising device address:

Definition of m_scan_param for advanced initialization:

My scan_init() function where I initialize the scanning module and set and enable the address filter. I have connection set to false as the advertising device is a beacon:

My scan_start() function. The application is crashing at line 153 with the app checking the ret variable, which I printed and learned that it is 9. I do not know what 9 signifies.

Here is my main function as you requested:

Do you know when the engineers will be back from Vacation? I have been having issues with this module for two months now and it is due in two weeks. Thank you for helping me 🙂

Best,

Maria

RE: Address Filter not working

Simonr — Fri, 30 Jul 2021 06:07:14 GMT

Hi Maria

Due to the summer vacation period here in Norway we are short on staff and delayed replies must be expected. I'm sorry for any inconvenience this might cause.

First off, have you double checked that the address you've set in the scan filter and on the advertising device is the same? Can you provide a snippet of code showing the main() loop of your application. Are you sure it starts scanning at all?

Best regards,

Simon