37.2.3 I3C Bus Configuration

An I3C bus can have the following compatible devices connected to it:

• I3C Primary Controller (with or without HDR support)
• I3C Secondary Controller (with or without HDR support)
• I3C Target (with or without HDR support)
• I²C Target (no HDR support)

An I3C bus is considered a pure bus when there are no active I²C devices present, otherwise it is considered a mixed bus. The I3C bus is always initially configured in SDR mode by the I3C Primary Controller. The I3C Secondary Controller, if present on the bus, operates as a Target to the Primary Controller initially, but has the capability to become the Controller on the bus temporarily. When the Secondary Controller becomes the Controller, the Primary Controller relinquishes its controller capabilities since the I3C protocol only allows one active Controller on the bus at any time. Figure 37-2 below shows an example of an interconnected block diagram of the I3C bus.