Bluetooth connection basic connection

RE: Bluetooth connection basic connection

dmleone — Fri, 08 Jul 2022 20:26:39 GMT

very helpful. Is there some built in functions that can either return true if and advertisement is showing itself to be a bonded device or is there some function I can call after I initially connect that can determine if the unit I am connected to has been previously bonded? I am not finding anything like an isBonded(struct bt_conn *conn) or isBonded(bt_addr_le_t addr) function of sorts. Something i could just test before i go attempt to change security levels

RE: Bluetooth connection basic connection

Kenneth — Fri, 08 Jul 2022 12:09:51 GMT

[quote user="dmleone"]But if I simply advertise, the central does not automatically connect. I have to initiate the conneciton manually some way. Is there a type or some way of calling a bond check for auto connect when seeing an advertisement?[/quote]

I know that is the case for many OS, because the OS will autoconnect some peripheral devices that support specific features the OS use (e.g. HID devices), also I believe some heart rate sensors also will auto connect, but other non-standardized profiles may not auto connect unless the user actively do so.

Kenneth

RE: Bluetooth connection basic connection

dmleone — Fri, 08 Jul 2022 11:44:26 GMT

This is how i assume it functions. I believe there are 128bytes of data actually transmitted on a BLE packet and we can manipulate 31 of those bytes. Inside the non-manipulatable portion, contains a MAC address. And it is in this non-manipulated data where bonding and re-connection code can be automated. Is this correct?

I have set up code and am able to establish a pair bond pair. I am sure I am bonded and paired as I will get a pairing_complete + security_changed callback the first pairing request and after that first initial pair and bond, subsequent connection result in only a security_changed callback feature.

But if I simply advertise, the central does not automatically connect. I have to initiate the conneciton manually some way. Is there a type or some way of calling a bond check for auto connect when seeing an advertisement?

RE: Bluetooth connection basic connection

Kenneth — Thu, 07 Jul 2022 11:05:03 GMT

A peripheral device that is advertising may or may not have bonded previsouly with the phone. Each advertisment packet contain some type of address, and the phone can based on the address know if it has been previously bonded or not, if previously bonded the phone typically will connect. It's also worth mentioning that a peripheral device that is advertising will typically have a list of previously bonded devices internally (e.g. whitelist), and typically the peripheral only allow phones that are in the list allow to connect, it's only if the user do an active choice that the peripheral allow other phones to connect and bond.

Kenneth