Connecting with nfc_ble_pair_lib

RE: Connecting with nfc_ble_pair_lib

Hung Bui — Thu, 26 Oct 2017 09:11:32 GMT

Good to know Rdecker. Happy to help :)

RE: Connecting with nfc_ble_pair_lib

rdecker — Thu, 26 Oct 2017 00:22:33 GMT

You are correct, adding uECC.c was my mistake as I found out in my last reply. Using the library .a file only works correctly. I did also add the PM_EVT_CONN_SEC_PARAMS_REQ event as mentioned in the changes when looking over the example's code. Everything seems to work fine on my phone now. I have had other issues with other friends phones but for now I will not worry about that and will write it off as them having older firmware. Thanks for the help.

RE: Connecting with nfc_ble_pair_lib

Hung Bui — Wed, 25 Oct 2017 12:37:37 GMT

I'm not sure why you need to include uecc.c file. As I can see in our example (both SDK v14 and v14.1) we only include the .lib file instead of the uecc.c source file. Note that there is a change in NFC BLE Pairing Library in SDK v14.1 that you need to modify if you porting your application from v14.0 to v14.1. Look at the Changes section.

RE: Connecting with nfc_ble_pair_lib

rdecker — Wed, 25 Oct 2017 04:54:50 GMT

So after copying over the examples main.c and sdk_config.h into my project and still having issues I figured out that the problem was in my build system (I'm using cmake and gcc). After a diffing I found that I compiled uECC.c but the example did not. For some reason including uECC.c created the DHKEY_FAILURE. Removing it from the sources list has fixed my issue. Just to be sure I added it back in and the DH failures returned.

Interestingly enough I remember setting up micro-ecc to fix a unresolved symbol error in the past. Perhaps it was required in 14.0.0 but is now unnecessary and in fact detrimental to 14.1.0. Very strange.

Hopefully if someone else stumbles upon this they won't spend the hours I did on it.

RE: Connecting with nfc_ble_pair_lib

Hung Bui — Tue, 24 Oct 2017 13:35:22 GMT

Have you also update the NFC library ?

Code 139 = 0x8B = BLE_GAP_SEC_STATUS_DHKEY_FAILURE

Could be something wrong with the OOB data to generate the key

Which phone did you use to test with ? I also experience some issues with Samsung S8 (not same error code though), when the Nexus phones worked fine.

"the board believes the connection is established but the phone does not" This will result the board disconnect because of timeout , after that can you connect and bond ?

RE: Connecting with nfc_ble_pair_lib

rdecker — Tue, 24 Oct 2017 09:57:55 GMT

Testing the example with SDK14.1.0, it does infact work correctly. However I am unable to get it to work in my personal project even after matching all relevant lines and config options.

Using NFC_PAIRING_MODE_LESC_... gives me a "app: Authorization failed with code: 139!". Switching to NFC_PAIRING_MODE_... (no lesc) bonds but then creates the above problem where the board believes the connection is established but the phone does not.

Any guidance would be appreciated. Perhaps I should make a new question for the authentication issue when using LESC modes in my code.

RE: Connecting with nfc_ble_pair_lib

Hung Bui — Mon, 23 Oct 2017 10:55:02 GMT

@rdecker: Are you sure it's the nfc library caused the advertising to stop ? I can see from the code that when BLE_GAP_EVT_DISCONNECTED occurs, we will call ble_advertising_start(). That what I also experience when testing with my phone. The device advertised after bonded.