Does Lyra support a Multi-Central Topology as a Peripheral?

Answer

Using Simplicity Studio SDK, a peripheral device can connect to a maximum of 32 centrals simultaneously (default is 4).  The number of connections can be increased from within Simplicity Studio by configuring the Bluetooth Core software component as described at the following Silicon Labs page:

https://docs.silabs.com/bluetooth/5.0/general/connections/multicentral-topology

However, while this is a maximum that can technically be supported the actual maximum on Lyra is 4 due to RAM size.

If using AT Interface application, 4 concurrent connections from a peripheral to multiple central devices are also supported. AT Interface provides two mutually exclusive modes of operation on start-up depending on the value of writable numeric parameter 100 (referred to as VSP or Bridge mode and non-VSP modes). Multiple concurrent connections can be made when configured for non-VSP mode.

As a peripheral device it will transmit connectable advertisements. A central device such as a smartphone can discover the peripheral and send a connection request at which point upon reception by the peripheral advertisements will be stopped. After a connection has been established the peripheral can then begin transmitting further advertisements allowing connections with further central devices.