The configuration frame interface (CFI) is a dedicated 128-bit programming bus used to configure the PL. The CFU is the only control for the CFI bus. The CFI bus protocol is translated by the CFU from AXI. The CFI bus transactions are sent to all CFRAMEs. Each CFRAME has a logic controller that decodes the row address to determine whether or not it should receive the CFI packet.
The CFI is pipelined as it travels through the CFRAMEs. The CFU monitors the CFI bandwidth and pending operations to ensure that the CFRAME can accept the data being sent.