Send and receive PHY packets

[pipe01]

I'm making an nRF52832 emulator and I'd like to be able to interact with it through a BLE connection. I can already read and write BLE PHY packets from/to it, and I'd like to use bumble in order to connect e.g. an android emulator to it. Is there any way to do this with bumble?

[barbibulle]

There are two ways Bumble could interface with the emulator:
1/ Communicate HCI packets with code running on the emulator (i.e run a "Controller" on the emulator). In this case, Bumble is the host stack, and the code running on the emulator is the controller. That's pretty simple (that works already today with physical nrfXX devices running Zephyr)
2/ Communicate with the emulator via the radio side. Since there's no equivalent, on the PHY side, to the HCI standard the exists on the host side, the emulated radio's PHY would need to exchange PHY packets with another controller that's compatible with those PHY packets. This could be another nRF52832 emulator, or it could be another emulated PHY. Bumble itself doesn't implement a PHY layer, but it does interface with RootCanal (either directly, or as embedded in netsim, which is part of Android Studio's emulator), which does implement an emulated PHY. RootCanal is itself an open source project (https://github.com/google/rootcanal). It does support exchanging PHY packets over TCP, so that's probably a good place to start. Once your emulator can communicate with RootCanal, then that opens up the possibility of communicating with Android emulators, as well as any other Bluetooth stack (including Bumble, but also other Bluetooth stacks that can use an external HCI interface, using Bumble's HCI bridge).

[pipe01]

Thank you for the thorough response, RootCanal looks very interesting!