Abstract: Circuitry comprises control circuitry to control an operating state of a data handling device of a set of two or more redundant data handling devices configured to perform identical data handling functions; the control circuitry being configured to control an operating state of the respective controlled data handling device as a state transition from a current operating state of that data handling device to a target operating state in response to the issue of a respective state change signal; the control circuitry comprising a detector responsive to issue of the state change signal in respect of a first threshold number representing some but not all of the data handling devices, to detect whether the state change signal is issued in respect of a further one or more of the devices so that a second threshold number of data handling devices is reached.

Abstract: An interconnection network is provided for managing data transfer between a plurality of nodes of an integrated circuit. The interconnection network has at least one transmission path originating from an upstream location of the interconnection network, each transmission path being arranged to transmit data blocks from the upstream location to an associated downstream location within that transmission path. Digest generation circuitry is used to generate digests for data blocks, and fault detection circuitry provided in association with the upstream location is arranged to determine presence of a fault condition in the interconnection network. The digest generation circuitry is arranged to generate an upstream digest for a given data block at the upstream location, and to generate a corresponding downstream digest for the given data block at the associated downstream location.

Abstract: An apparatus and method for transmitting signals between two clock domains in which at least one of a phase and a frequency of clock signals in the two clock domains is misaligned. The apparatus includes a first primary interface and a first redundant interface in the first clock domain for receiving a primary signal and a first checking signal respectively, and a second primary interface and second redundant interface in the second clock domain for outputting the primary signal and a second redundant signal respectively. The primary signal and the checking signals are separated by a predetermined time delay and the second checking signal is generated in the second clock domain based on the primary signal. Checking circuitry is provided in the second clock domain to perform an error checking procedure based on the two checking signals and to provide the second checking signal to the second redundant interface.

Abstract: An interconnection network is provided for managing data transfer between a plurality of nodes of an integrated circuit. The interconnection network has at least one transmission path originating from an upstream location of the interconnection network, each transmission path being arranged to transmit data blocks from the upstream location to an associated downstream location within that transmission path. Digest generation circuitry is used to generate digests for data blocks, and fault detection circuitry provided in association with the upstream location is arranged to determine presence of a fault condition in the interconnection network. The digest generation circuitry is arranged to generate an upstream digest for a given data block at the upstream location, and to generate a corresponding downstream digest for the given data block at the associated downstream location.

Abstract: An apparatus and method for transmitting signals between two clock domains in which at least one of a phase and a frequency of clock signals in the two clock domains is misaligned. The apparatus includes a first primary interface and a first redundant interface in the first clock domain for receiving a primary signal and a first checking signal respectively, and a second primary interface and second redundant interface in the second clock domain for outputting the primary signal and a second redundant signal respectively. The primary signal and the checking signals are separated by a predetermined time delay and the second checking signal is generated in the second clock domain based on the primary signal. Checking circuitry is provided in the second clock domain to perform an error checking procedure based on the two checking signals and to provide the second checking signal to the second redundant interface.

Abstract: Circuitry comprises control circuitry to control an operating state of a data handling device of a set of two or more redundant data handling devices configured to perform identical data handling functions; the control circuitry being configured to control an operating state of the respective controlled data handling device as a state transition from a current operating state of that data handling device to a target operating state in response to the issue of a respective state change signal; the control circuitry comprising a detector responsive to issue of the state change signal in respect of a first threshold number representing some but not all of the data handling devices, to detect whether the state change signal is issued in respect of a further one or more of the devices so that a second threshold number of data handling devices is reached.