Abstract: A data processing apparatus and method are provided that use monitoring circuitry to control operating parameters of the data processing apparatus. The data processing apparatus has functional circuitry for performing data processing, the functional circuitry including error correction circuitry configured to detect errors in operation of the functional circuitry and to repair those errors in operation. Tuneable monitoring circuitry monitors a characteristic indicative of changes in signal propagation delay within the functional circuitry and produces a control signal dependent on the monitored characteristic. In a continuous tuning mode operation, the tuneable monitoring circuitry modifies the dependency between the monitored characteristic and the control signal in dependence upon certain characteristics of the errors detected by the error correction circuitry.

Abstract: A data processing apparatus has error detection units each configured to generate an error signal if a first and second sample of a signal associated with execution of an instruction differ. Error value generation circuitry generates an error value showing if any of the error detection units have generated the error signal. Error value stabilisation circuitry performs a stabilisation procedure comprising re-sampling the error value to remove metastability. Error recovery circuitry initiates re-execution of the instruction if the error value is asserted. Count circuitry holds a counter value in association with the error value, the counter value set to a predetermined value when the error value is generated and decremented each time the error value is re-sampled prior to reaching the error value stabilisation circuitry. The error value bypasses the stabilisation procedure if the counter value is zero before the error value reaches the error value stabilisation circuitry.

Abstract: A data processing system 2 is used to perform processing operations to generate a result value. The processing circuitry which generates the result value has an error resistant portion 32 and an error prone portion 30. The probability of an error in operation of the error prone portion for a given set of operating parameters (clk, V) is greater than the probability of an error for that same set of operating parameters within the error resistant portion. Error detection circuitry 38 detects any errors arising in the error prone portion. Parameter control circuitry 40 responds to detected errors to adjust the set of operating parameters to maintain a non-zero error rate in the errors detected by the error detection circuitry. Errors within the one or more bits generated by the error prone portion are not corrected as the apparatus is tolerant to errors occurring within such bit values of the result value.

Abstract: An integrated circuit 114 includes processing pipeline circuitry 40 comprising a plurality of pipeline stages 44, 46, 48 separated by respective signal value storage circuitry 48, 50, 52. Timing detection circuitry 54, 56, 58 coupled to the processing pipeline circuitry serves to detect as timing violations any signal transitions arrive at the signal value storage circuits outside respective nominal timing windows. Error detection circuitry 66 triggers an error correcting response if the timing detection circuitry indicates a predetermined pattern comprising a plurality of timing violations spread over a plurality of clock cycles of a clock signal CK controlling the processing pipeline circuitry. The predetermined pattern may be two consecutive timing violations.

Abstract: An integrated circuit is provided with error detection circuitry and error repair circuitry. Error tolerance circuitry is responsive to a control parameter to selectively disable the error repair circuitry. The control parameter is dependent on the processing performed within the circuit. For example, the control parameter may be generated in dependence upon the program instruction being executed, the output signal value which is in error, the previous behavior of the circuit or in other ways.

Abstract: An apparatus and method are provided for detecting an approaching error condition within a data processing apparatus and includes a sequential storage structure arranged to latch an output signal generated by combinatorial circuitry dependent on a second clock signal. The sequential storage structure has a main storage element to latch a value of the output signal for provision to subsequent combinatorial circuitry. The sequential storage structure can be operated in either first or second modes of operation where, in the first mode, the predetermined timing window is ahead of a time at which the main storage element latches said value of the output signal enabling an approaching setup timing error to be detected. In the second mode, the predetermined timing window is after the time at which the main storage element latches said value of the output signal where an approaching hold timing error is detected.

Abstract: A D-type flip-flop includes tristate inverter circuitry passing a processing signal through to storage circuitry 8 from where the processing signal passes via a transmission gate to slave storage circuitry. A transition detector is coupled to the input node of the storage circuitry and serves to generate an error signal if a transition is detected upon that input node during an error detecting period. Other forms of this technique may provide clock gating circuitry.

Abstract: An integrated circuit comprising a plurality of sensors configured to sense variations in supply voltage levels at points within the integrated circuit is disclosed. The plurality of sensors are distributed across the integrated circuit and have transistor devices such that process variations in the transistor devices within the sensors are such that a sensing result will have a random voltage offset that has a predetermined probability of lying within a pre-defined voltage offset range. The integrated circuit is configured to transmit results from multiple ones of the plurality of sensors to processing circuitry such that the variations in the supply voltage levels can be determined with a voltage offset range that is reduced compared to the pre-defined voltage offset range.

Abstract: A data processing apparatus has error detection units each configured to generate an error signal if a first and second sample of a signal associated with execution of an instruction differ. Error value generation circuitry generates an error value showing if any of the error detection units have generated the error signal. Error value stabilisation circuitry performs a stabilisation procedure comprising re-sampling the error value to remove metastability. Error recovery circuitry initiates re-execution of the instruction if the error value is asserted. Count circuitry holds a counter value in association with the error value, the counter value set to a predetermined value when the error value is generated and decremented each time the error value is re-sampled prior to reaching the error value stabilisation circuitry. The error value bypasses the stabilisation procedure if the counter value is zero before the error value reaches the error value stabilisation circuitry.

Abstract: A data processing apparatus executes instructions in a sequence of pipelined execution stages. An error detection unit twice samples a signal associated with execution of an instruction and generates an error signal if the samples differ. An exception storage unit maintains an age-ordered list of entries corresponding to instructions issued to the execution pipeline and can mark an entry to show if the error signal has been generated in association with that instruction. A timer unit is responsive to generation of the error signal to initiate timing of a predetermined time period. An error recovery unit initiates a soft pipeline flush procedure if an oldest pending entry in the list has said error marker stored in association therewith and initiates a hard pipeline flush procedure if said predetermined time period elapses, said hard flush procedure comprising resetting said pipeline to a predetermined state.

Abstract: An electronic device is described which receives data from a transmitting device via a communications channel. The electronic device comprises digital processing circuitry arranged to process the data received via the communications channel to generate output data, error detection circuitry arranged to detect errors in the output data, and monitoring circuitry arranged to monitor the quality of digital processing conducted by the digital processing circuitry and generate digital performance data indicative of the monitored quality of digital processing. The electronic device also comprises control circuitry responsive to error information comprising errors detected by the error detection circuitry and the performance data generated by the monitoring circuitry to modify the operation of one or both of the transmitting device and the electronic device.

Abstract: Signal value storage circuitry 2 includes transparent storage circuitry 4, transition detector circuitry 6 and error detecting circuitry 8. The transition detector circuitry serves to generate a detection pulse when a signal transition is detected at a signal node NS within the transparent storage circuitry. The error detecting circuitry generates an error indicating signal when this detection pulse overlaps in time with the non-transparent phase of a pulse clock signal controlling the signal valve storage circuitry for at least an overlap period TOV.

Abstract: A data processing apparatus configured to operate in a voltage and frequency operating region that is located beyond a safe region where errors do not arise, but within operating region limits such that the errors are rare. The data processing apparatus comprises: error detection circuitry and error recovery circuitry; the error detection circuitry being configured to determine if a signal sampled in the processing apparatus changes within a time window occurring after the signal has been sampled and during a same clock cycle as the sampling and to signal an error if the signal does change.

Abstract: A D-type flip-flop 2 includes tristate inverter circuitry 4, 6 passing a processing signal through to storage circuitry 8 from where the processing signal passes via a transmission gate 10 to slave storage circuitry 12. A transition detector 16 is coupled to the input node nm of the storage circuitry 8 and serves to generate an error signal if a transition is detected upon that input node during an error detecting period. Other forms of this technique may provide clock gating circuitry.

Abstract: A processor 2 is responsive to a stream of program instructions to issue program instructions under control of scheduling circuitry 6 to respective execution units 24 for execution. The execution units 24 can include error detecting circuitry 32 for detecting a change in an output signal which occurs after the output signal has latched and during an error detecting period following the latching of the output signal. The scheduling circuitry 6 is arranged so as to suppress issue of program instructions to an execution unit 24 having such error detecting circuitry 32 on consecutive processing cycles.

Abstract: Transition detection circuitry for detecting during multiple clock cycles, transitions occurring within a detection period in each of said multiple clock cycles at a plurality of nodes within a circuit is disclosed. The transition detection circuitry comprises: a clock signal generator for generating a detection clock signal from a clock signal clocking a sampling element within said circuit, said detection clock signal defining said detection period; a plurality of transition detectors for detecting transitions at respective ones of said plurality of nodes during said detection period, each of said plurality of transition detectors being clocked by said detection clock signal; and combining circuitry for combining said detected transitions output by said plurality of transition detectors to generate a composite transition detection signal.

Abstract: A data processing apparatus and method are provided that use monitoring circuitry to control operating parameters of the data processing apparatus. The data processing apparatus has functional circuitry for performing data processing, the functional circuitry including error correction circuitry configured to detect errors in operation of the functional circuitry and to repair those errors in operation. Tuneable monitoring circuitry monitors a characteristic indicative of changes in signal propagation delay within the functional circuitry and produces a control signal dependent on the monitored characteristic. In a continuous tuning mode operation, the tuneable monitoring circuitry modifies the dependency between the monitored characteristic and the control signal in dependence upon certain characteristics of the errors detected by the error correction circuitry.

Abstract: An instruction processing pipeline 6 is provided. This has error detection and error recovery circuitry 20 associated with one or more of the pipeline stages. If an error is detected within a signal value within that pipeline stage, then it can be repaired. Part of the error recovery may be to flush upstream program instructions from the instruction pipeline 6. When multi-threading, only those instructions from a thread including an instruction which has been lost as a consequence of the error recovery need to be flushed from the instruction pipeline 6. Instruction can also be selected for flushing in dependence upon characteristics such as privileged level, number of dependent instructions etc.

Abstract: Tuning limits are set for operational parameters in a processing stage within a data processing apparatus for processing a signal and outputting it at an output time. If a signal output between the output time and a predetermined time later does not have a stable value, the predetermined time later being before a next output time, an error is signaled. A tuning circuit adjusts an operational parameter of the processing stage in accordance with a tuning limit. A signal passing along a critical path of the processing stage tuned to the tuning limit is expected to reach the output of the processing stage at a preset time later than the output time, the preset time being less than the predetermined time.

Abstract: An integrated circuit 2 includes logic circuitry 10 and sequential storage elements 8. Both the logic circuit 10 and sequential storage elements 8 can be subject to particle strikes giving rise to single event upset errors. These single event upset errors can be detected by detecting a transition in the stored value stored by the sequential storage elements 8 occurring outside of a valid transition period associated with that sequential storage element 8.