Devices exchange control signals with each other to ensure proper operation of an overall system. For instance, in a communication system, a baseband processor and a transceiver communicate with each other to exchange information for controlling the respective signal processing parts of the baseband processor and the transceiver. While Serial Peripheral Interfaces (SPIs) can be used, SPI can be extremely slow, and does not provide a protocol for allowing a complex set of control signals to be exchanged between the baseband processor and transceiver. The present disclosure describes a fast control interface which can support various modes of operation in allowing two devices to communicate with each other quickly and effectively.