CCCs are the commands that an I3C Controller uses to communicate to some or all of the Targets on the I3C Bus. The CCCs are sent to the I3C Broadcast address (which is 7’h7E) so as not to interfere with normal messages sent to a Target. In other words, CCCs are separated from the standard “content protocol” used by normal messages, such as Private Write and Read transfers (in SDR Mode).
The CCCs are used for standard operations like enabling/disabling events, managing I3C-specific features, and other Bus operations. CCCs can be either Broadcasted (i.e., sent to all Devices on the I3C Bus), or else Directed to specific Devices on the I3C Bus (i.e., by Address). All CCC command number values are allocated by MIPI Alliance, and some values are reserved for specific purposes including MIPI Alliance enhancements and other extensions (see Q18.4, "What are Vendor / Standard Extension CCCs, who can use them, and how are they differentiated among different uses?").