[BLE] LAIRD BL652 Advertising while in a connection

Question

Hello, 
 I work on module BLE LAIRD BL652 and I'm a BLE peripheral. I have tried to make a BASIC program for advertising while in a connection but without success. 
 As you know, there are 4 types of advertising packets:
(1) Give data and allow no incoming connection - used to broadcast small blocks of data.
(2) Give data and only allow a peer to request one more packet of data
(3) Give data and invite connection from a specific address (i.e. a bonded/trusted relationship)
(4) Give data and invite connection from anyone - promiscuous usage 
 According to a FAQ of Lairdtech: "Although a slave can only be connected to one master, it is allowed to advertise types (1) and (2) while in a connection." 
 Somes people can help me ?

endnode · Accepted Answer

Hi, 
 Thanks for explaining us your view on "advertising" but I'm afraid you are mixing up some terms in BLE stack layers and procedures. It's true that life-time of each BLE device has two phases (which typically repeat again and again): advertising/scanning and then connection link (mater or slave). In the first part one device plays the role of broadcaster/advertiser and can send various types of packets. Based on their type they can be connectable or not, scannable or not, directed or undirected. If the broadcaster is connectable then suitable observer can issue connection request and then observer becomes Master on Link Layer while broadcaster becomes Slave. 
 Now to your case: if BLE stack allows it can be in active connection link and still perform other roles in parallel (the firmware needs to time multiplex the processing because it has typically just one radio front-end and one computing core but that's typically OK for BLE and similar technologies because they need processing and radio only for fraction of total time and they also can miss some slots without terminating the link). However if you want to use LAIRD BL652 module (which is based on Nordic nRF52 chip) with stack/firmware/bootloader from the vendor then you need to discuss with them and their documentation how exactly your firmware can become Broadcaster, then Slave and Broadcaster in parallel. We could only advise if you use some well-known stack such as Nordic S132 Soft Device. 
 Good luck!