Abstract: A transition detection circuit (20) and method of operation of such a circuit are provided, the transition detection circuit (20) having pulse generation circuitry (25) to receive an input signal (10) and to generate a pulse signal in response to a transition in the input signal, and pulse detection circuitry (30) to assert an error signal on detection of the pulse signal generated by the pulse generation circuitry. The pulse generation circuitry has pulse control circuitry (35) to control a property of the pulse signal dependent on a timing window indication signal (40). In particular, when the pulse signal is generated at least partly whilst the timing window indication signal is set, the pulse control circuitry (35) controls the property of the pulse signal such that generated pulse signal is detected by the pulse detection circuitry (20).

Abstract: A storage bitcell comprising a first inverter cross-coupled with a second inverter, both the first and second inverter being in a path between a first potential and a second potential; wherein a first isolator is connected in the path between the first inverter and the first potential. The storage bitcell has particular application as Static Random-Access Memory (SRAM) circuitry.

Abstract: An apparatus and method are provided for detecting a resonant frequency giving rise to an impedance peak in a power delivery network used to provide a supply voltage. The apparatus includes resonant frequency detection circuitry that comprises test frequency control circuitry and a loading circuit. The test frequency control circuitry is arranged to generate control signals to indicate a sequence of test frequencies. A loading circuit is controlled by the control signals and operates from the supply voltage. In particular, in response to each test frequency indicated by the control signals, the loading circuit draws a duty-cycled current load through the power delivery network at that test frequency. Operation of the loading circuit produces a measurable property whose value varies in dependence on the supply voltage, thus enabling the resonant frequency to be determined from a variation in the value of that measurable property.

Abstract: Various implementations described herein are directed to an integrated circuit. The integrated circuit may include a comparator stage, a resistor, a capacitor, and active switches arranged to provide a clock signal having a time period that is independent of a first source voltage. Independence may be achieved by using a second source voltage derived from the first source voltage as a fixed ratio.

Abstract: A storage bitcell comprising a first inverter cross-coupled with a second inverter, both the first and second inverter being in a path between a first potential and a second potential; wherein a first isolator is connected in the path between the first inverter and the first potential. The storage bitcell has particular application as Static Random-Access Memory (SRAM) circuitry.

Abstract: A memory circuit comprises an array of data storage elements; access circuitry to access a data bit, stored by a data storage element enabled for access, by an access signal for that data storage element; and control circuitry to enable groups of data storage elements for access, the groups having a group size, the group size being one or more, the access signals for data storage elements in a group being combined to provide a combined access signal common to that group of data storage elements; the control circuitry being configured to selectively operate in at least a first mode and a second mode, the group size in the first mode being different to the group size in the second mode.

Abstract: Various implementations described herein are directed to an integrated circuit. The integrated circuit may include a comparator stage, a resistor, a capacitor, and active switches arranged to provide a clock signal having a time period that is independent of a first source voltage. Independence may be achieved by using a second source voltage derived from the first source voltage as a fixed ratio.

Abstract: An electronic device (20) has a clock path (24) for propagating a clock signal and a clock propagating element (26) on the clock path. An analogue element (30) coupled to the clock path (24) varies, in dependence on an analogue level of a first signal (32), a switching delay for the clock propagating element (26) to trigger a transition of the clock signal. The first signal is a digitally sampled signal. This provides a mechanism for providing a fast reduction in clock frequency even if the first signal is a metastable signal, which is useful for avoiding errors causes by voltage drops.

Abstract: An apparatus and method are provided for detecting a resonant frequency giving rise to an impedance peak in a power delivery network used to provide a supply voltage. The apparatus includes resonant frequency detection circuitry that comprises test frequency control circuitry and a loading circuit. The test frequency control circuitry is arranged to generate control signals to indicate a sequence of test frequencies. A loading circuit is controlled by the control signals and operates from the supply voltage. In particular, in response to each test frequency indicated by the control signals, the loading circuit draws a duty-cycled current load through the power delivery network at that test frequency. Operation of the loading circuit produces a measurable property whose value varies in dependence on the supply voltage, thus enabling the resonant frequency to be determined from a variation in the value of that measurable property.

Abstract: An operating parameter method and circuitry are provided that generate operating parameter signals that are compensated for noise. Such operating parameter circuitry includes control loop circuitry that operates from a first power supply to provide an operating parameter signal to functional circuitry operating from a second power supply separate from the first power supply. The control loop circuitry comprises generator circuitry to generate the operating parameter signal based on an input signal. Replica generator circuitry operates from the second power supply to generate a further operating parameter signal based on the input signal. Adjustment circuitry performs a comparison on the operating parameter signal and the further operating parameter signal and causes an adjusted input signal to be produced in dependence on a result of the comparison. The adjusted input signal is received by the generator circuitry.

Abstract: An instruction processing pipeline having error detection and error recovery circuitry 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. When multi-threading, only those instructions from a thread including an instruction which has been lost as a consequence of the error recovery need be flushed from the instruction pipeline. The instruction pipeline may additionally/alternatively be provided with more than one main storage element associated with each signal value with these main storage elements used in an alternating fashion such that if a signal value has been erroneously captured and needs to be repaired, there is still available a main storage element to properly capture the signal value corresponding to the following program instruction.

Abstract: A circuit delay monitoring apparatus has a ring oscillator with a plurality of delay elements, a signal transition being propagated through the delay elements of the ring oscillator, and a plurality N of sampling points being distributed around the ring oscillator. Selection circuitry selects, in dependence on the indication of the current location of the signal transition generated by the fine sampling circuitry, one of the M transition counter circuits whose associated location is greater than said predetermined amount from the current location of the signal transition. Output generation circuitry then generates a count indication for a reference time period dependent on a sampled count value of the transition counter circuit selected by the selection circuitry, the indication of the current location of the signal transition within the ring oscillator, and reference count data relating to the start of the reference time period.

Abstract: An operating parameter method and circuitry are provided that generate operating parameter signals that are compensated for noise. Such operating parameter circuitry includes control loop circuitry that operates from a first power supply to provide an operating parameter signal to functional circuitry operating from a second power supply separate from the first power supply. The control loop circuitry comprises generator circuitry to generate the operating parameter signal based on an input signal. Replica generator circuitry operates from the second power supply to generate a further operating parameter signal based on the input signal. Adjustment circuitry performs a comparison on the operating parameter signal and the further operating parameter signal and causes an adjusted input signal to be produced in dependence on a result of the comparison. The adjusted input signal is received by the generator 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 integrated circuit including 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: An integrated circuit includes processing pipeline circuitry comprising a plurality of pipeline stages separated by respective signal value storage circuitry. Timing detection circuitry 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 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 controlling the processing pipeline circuitry. The predetermined pattern may be two consecutive timing violations.

Abstract: A circuit delay monitoring apparatus has a ring oscillator with a plurality of delay elements, a signal transition being propagated through the delay elements of the ring oscillator, and a plurality N of sampling points being distributed around the ring oscillator. Selection circuitry selects, in dependence on the indication of the current location of the signal transition generated by the fine sampling circuitry, one of the M transition counter circuits whose associated location is greater than said predetermined amount from the current location of the signal transition. Output generation circuitry then generates a count indication for a reference time period dependent on a sampled count value of the transition counter circuit selected by the selection circuitry, the indication of the current location of the signal transition within the ring oscillator, and reference count data relating to the start of the reference time period.

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 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: 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.