Getting peer address (of central - android/iOS) and storing it in whitelist

[Devanshi1510]

I am using BLE peripheral UART application from nordic SDK version 15.2.0 SoftDevice S140 PCA10056 nRF52840 Development kit on Embedded Segger studio operating system - Windows 8.1 Pro. I want to understand how to get or retrieve the address of the android/iOS device when connection occurs between peripheral and central(android). Further I want to activate whitelist option to store the peer address which are allowed to access it. On central, am using nRF toolbox android application and using nordic uart to connect to peripheral.  I tried to implement this code snippet:

//Connected device
 ble_gap_addr_t addr = p_ble_evt->evt.gap_evt.params.connected.peer_addr;
 memcpy(addr.addr, p_ble_evt->evt.gap_evt.params.connected.peer_addr.addr, 6);
 mprintf(UART," Connected to %X:%X:%X:%X:%X:%X AddrType:0x0%d\n",
 addr.addr[5],addr.addr[4],addr.addr[3],
 addr.addr[2],addr.addr[1],addr.addr[0],
 p_ble_evt->evt.gap_evt.params.connected.peer_addr.addr_type);

But I get this error and when I try to define UART with 48 bits it gives 2nd and 3rd error.

1.  'UART' undeclared (first use in this function)

2.Output/ble_app_uart_pca10056_s140 Release/Obj/main.o: In function `ble_evt_handler':

3. undefined reference to `mprintf'

i am quite new to this, so any guidance would be helpful.

But by analysising further, I got to know that android and iOS uses random private resolvable address hence it always gives different address on every connection.

So,.in that case how will I get whitelist option enabled as in like to allow only some android phones to connect and ignore other ones who are not in whitelist. 

Please hoping to get help soon. 

[Jørgen Holmefjord]

Hi,

I have never heard of function mprintf in C before, and it does not seem to be defined in your project either. Did you mean printf? There is also no symbol 'UART' defined in your project. If you want to use printf to print strings to UART, this is handled by retarget functions in the SDK in combination with app_uart library.

Best regards,
Jørgen

[Jørgen Holmefjord]

Try this instead:

printf("Connected to %X:%X:%X:%X:%X:%X AddrType:0x0%d\n", 
addr.addr[5],addr.addr[4],addr.addr[3],
addr.addr[2],addr.addr[1],addr.addr[0],
p_ble_evt->evt.gap_evt.params.connected.peer_addr.addr_type);

That user must be using a custom function for printing data. If this does not work, you can try NRF_LOG_INFO().

[Devanshi1510]

Hey, this worked for me but I am getting different address than of my android phone. I think it is because newer android versions uses private resolvable address also Addrtype is 0x02. So, is there any way to identify only particular android phones which can access to BLE peripheral. I heard about whitelist option but it wont work in private resolvable address scenerio. 

[Jørgen Holmefjord]

Please have a look at these threads: 

https://devzone.nordicsemi.com/f/nordic-q-a/3235/whitelist-private-resolvable-address

https://devzone.nordicsemi.com/f/nordic-q-a/12083/resolving-private-resolvable-addresses

[Devanshi1510]

Hi , I followed this link: https://devzone.nordicsemi.com/f/nordic-q-a/12083/resolving-private-resolvable-addresses 

I got results like for 10 minutes  peer address remains same, but then changes to different address. I need to identify peer as uniquely identity and store it in whitelist.