Problem in advertising ibeacon in NRF52840

Question

Hi 
 i want to create a bluetooth beacon which should get input in gatt(UUID,name,major,minor..then it should be advertise with the new UUID. 
 Iam configuring it with ibeacon.i can get the payload through gatt.but when readvertising there is an issue. 
 iam facing error in this line 
 BT_DATA ( BT_DATA_MANUFACTURER_DATA , manufacturer_data , MANUFACTURER_DATA_LENGTH ), 
 my error is 
 C:/ncs/v2.8.0/zephyr/include/zephyr/bluetooth/bluetooth.h:474:25: error: initializer element is not constant 474 | .data = (const uint8_t *)(_data), \ | ^ C:/Users/Sara/Documents/PlatformIO/Projects/workspace/ibeacon/src/main.c:219:5: note: in expansion of macro 'BT_DATA' 219 | BT_DATA(BT_DATA_MANUFACTURER_DATA, manufacturer_data, MANUFACTURER_DATA_LENGTH), // Use sizeof to get length | ^~~~~~~ C:/ncs/v2.8.0/zephyr/include/zephyr/bluetooth/bluetooth.h:474:25: note: (near initialization for 'ad[1].data') 474 | .data = (const uint8_t *)(_data), \ | ^ C:/Users/Sara/Documents/PlatformIO/Projects/workspace/ibeacon/src/main.c:219:5: note: in expansion of macro 'BT_DATA' 219 | BT_DATA(BT_DATA_MANUFACTURER_DATA, manufacturer_data, MANUFACTURER_DATA_LENGTH), // Use sizeof to get length | ^~~~~~~

static ssize_t write_received_data ( struct bt_conn * conn , const struct bt_gatt_attr * attr , 
 const void * buf , uint16_t len , uint16_t offset , uint8_t flags ) 
 { 
 if ( len > MAX_STRING_SIZE - 1 ) { 
 return BT_GATT_ERR ( BT_ATT_ERR_INVALID_ATTRIBUTE_LEN ); 
 } 
 
 // Copy the received data 
 memcpy ( received_data , buf , len ); 
 received_data [ len ] = ' \0 ' ; // Null-terminate the received data 
 printk ( "Received data: %s 
 " , received_data ); 
 
 // Parse the received JSON into the parameters structure 
 int ret = json_obj_parse ( received_data , sizeof ( received_data ), 
 parameters_descr , ARRAY_SIZE ( parameters_descr ), 
 & params ); 
 if ( ret < 0 ) { 
 printk ( "JSON Parse Error: %d 
 " , ret ); 
 return len ; 
 } 
 
 // Print parsed values for verification 
 printk ( "Device Name: %s , UUID: %s , TX Power: %d , Major: %d , Minor: %d 
 " , 
 params . name , params . uuid , params . TX , params . Major , params . Minor ); 
 
 // Copy the device name to the buffer for advertising 
 strncpy ( name_buffer , params . name , sizeof ( name_buffer ) - 1 ); 
 name_buffer [ sizeof ( name_buffer ) - 1 ] = ' \0 ' ; // Ensure null-termination 
 
 // Set the TX power level 
 set_tx_power ( BT_HCI_VS_LL_HANDLE_TYPE_ADV , 0 , params . TX ); 
 
 // Convert UUID, Major, and Minor to their respective hex representations 
 uint8_t uuid_hex [ 16 ]; 
 uint8_t major_hex [ 2 ]; 
 uint8_t minor_hex [ 2 ]; 
 
 uuid_string_to_hex ( params . uuid , uuid_hex , sizeof ( uuid_hex )); 
 
 major_hex [ 0 ] = ( params . Major >> 8 ) & 0xFF ; 
 major_hex [ 1 ] = params . Major & 0xFF ; 
 minor_hex [ 0 ] = ( params . Minor >> 8 ) & 0xFF ; 
 minor_hex [ 1 ] = params . Minor & 0xFF ; 
 
 uint8_t manufacturer_data [] = { 
 0x4c , 0x00 , // Apple Manufacturer ID 
 0x02 , 0x15 , // iBeacon type 
 uuid_hex [ 0 ], uuid_hex [ 1 ], uuid_hex [ 2 ], uuid_hex [ 3 ], uuid_hex [ 4 ], uuid_hex [ 5 ], 
 uuid_hex [ 6 ], uuid_hex [ 7 ], uuid_hex [ 8 ], uuid_hex [ 9 ], uuid_hex [ 10 ], uuid_hex [ 11 ], 
 uuid_hex [ 12 ], uuid_hex [ 13 ], uuid_hex [ 14 ], uuid_hex [ 15 ], // UUID 
 major_hex [ 0 ], major_hex [ 1 ], // Major 
 minor_hex [ 0 ], minor_hex [ 1 ], // Minor 
 IBEACON_RSSI // RSSI 
 }; 
 
 static struct bt_data ad [] = { 
 BT_DATA ( BT_DATA_FLAGS , BT_LE_AD_NO_BREDR , 1 ), 
 BT_DATA ( BT_DATA_MANUFACTURER_DATA , manufacturer_data , MANUFACTURER_DATA_LENGTH ), // Use sizeof to get length 
 };

AMarch01 · Accepted Answer

Well, manufacturer_data[] appears to be an autogenerated data type that will be on the stack of write_received_data and will disappear when the function ends. So, as the error says, it isn't a constant. The advertising array ad[] will be pointing at the manufacturer_data array... perhaps you could get away with making the array global and modifying the bytes in it?

Hieu · Answer

I agree with the answer by AMarch01. 
 There is just one unrelated thing I would like to add. You might want to check with Apple documentation or support if the feature you are trying to implement is compliant with their specs. If I recall correctly, part of an iBeacon's purpose is to help with location. If its advertising data changes, the location data of the ecosystem can be affected.

Problem in advertising ibeacon in NRF52840

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