In a system for performing clock generation for each semiconductor device, synchronization between the semiconductor devices is achieved without causing a count value in a counter to be discontinuously changed. A semiconductor device 1 includes a clock oscillator 2, a counter 3 configured to count the number of clocks, a periodic register 4 in which a value corresponding to a period for synchronization is set, a comparison circuit 5 configured to compare the count value in the counter 3 with the set value in the periodic register 4, a match flag register 6 in which a predetermined value is set when the count value coincides with the set value, a match output terminal 7 configured to output the value in the match flag register 6 from the own semiconductor device, a match input terminal 8 to which a value output from another semiconductor device to be synchronized is input, and a reset circuit configured to reset the counter 3 and the match flag register 6 when both the value in the match flag register 6 of the own semiconductor device and the value input to the match input terminal 8 become a predetermined value.

Aspects of the disclosure are directed to reducing clock-ungating induced voltage droop by determining a maximum frequency value associated with an output clock waveform; modulating a clock frequency of the output clock waveform for a first time duration based on a first programmable mask pattern or a first Boolean function; and determining if either the first programmable mask pattern or the first Boolean function should be changed. In accordance with one aspect, a voltage droop mitigation circuit includes a control logic for receiving an input clock waveform and a clock enable signal waveform and for outputting a gated clock enable signal waveform; a latch coupled to the control logic, the latch for holding a state of the gated clock enable signal waveform and a AND gate coupled to the latch, the AND gate for outputting an output clock waveform.

Apparatus comprises master counter circuitry to generate a master count signal in response to a clock signal; slave counter circuitry responsive to the clock signal to generate a respective slave count signal; and a synchronisation connection providing signal communication between the master counter circuitry and the slave counter circuitry; the master counter circuitry being configured to provide to the slave counter circuitry via the synchronisation connection: (i) data indicative of a count offset value and (ii) a timing signal defining a timing relationship between the clock signal and the count offset value; and the slave counter circuitry being configured, during a synchronisation operation for that slave counter circuitry, to initialise a counting operation of that slave counter circuitry in response to the data indicative of the count offset value and a timing signal provided by the master counter circuitry.

Aspects of the disclosure are directed to reducing clock-ungating induced voltage droop by determining a maximum frequency value associated with an output clock waveform; modulating a clock frequency of the output clock waveform for a first time duration based on a first programmable mask pattern or a first Boolean function; and determining if either the first programmable mask pattern or the first Boolean function should be changed. In accordance with one aspect, a voltage droop mitigation circuit includes a control logic for receiving an input clock waveform and a clock enable signal waveform and for outputting a gated clock enable signal waveform; a latch coupled to the control logic, the latch for holding a state of the gated clock enable signal waveform and a AND gate coupled to the latch, the AND gate for outputting an output clock waveform.

A crystal oscillator is started in a high power mode for a certain period of time to ensure starting oscillation with average grade crystals, then once the certain time period is over the oscillator switches into a low power mode and sustains oscillation with energy pulses triggered by and synchronized with the oscillator output frequency. These energy pulses may be generated on the positive, negative or both positive and negative edges of the clock output waveform.

The present application relates to a system hosting a monotonic counter and a method of operating the system. The system comprises a non-volatile memory (110) for holding a save counter value and a volatile memory (120) for maintaining a current counter value. The system (100) is configured during a startup phase to retrieve the saved counter value of the monotonic counter from the non-volatile memory (110); to detect whether a previous shutdown of the system (100) was an uncontrolled shutdown; and to adjust the retrieved counter value in accordance with a step size (130) provided at the system (100) in case an previous uncontrolled shutdown is detected.

In a system for performing clock generation for each semiconductor device, synchronization between the semiconductor devices is achieved without causing a count value in a counter to be discontinuously changed. A semiconductor device 1 includes a clock oscillator 2, a counter 3 configured to count the number of clocks, a periodic register 4 in which a value corresponding to a period for synchronization is set, a comparison circuit 5 configured to compare the count value in the counter 3 with the set value in the periodic register 4, a match flag register 6 in which a predetermined value is set when the count value coincides with the set value, a match output terminal 7 configured to output the value in the match flag register 6 from the own semiconductor device, a match input terminal 8 to which a value output from another semiconductor device to be synchronized is input, and a reset circuit configured to reset the counter 3 and the match flag register 6 when both the value in the match flag register 6 of the own semiconductor device and the value input to the match input terminal 8 become a predetermined value.

The present invention provides a fractional frequency divider, wherein the fractional frequency divider includes a plurality of registers, a counter, a control signal generator and a clock gating circuit. Regarding the plurality of registers, at least a portion of the registers are set to have values The counter is configured to sequentially generate a plurality of counter values, wherein the plurality of counter values correspond to the at least a portion of the registers, respectively, and the plurality of counter values are generated repeatedly The control signal generator is configured to generate a control signal based on the received counter value and the value of the corresponding register. The clock gating circuit is configured to refer to the control signal to mask or not mask an input clock signal to generate an output clock signal.

A semiconductor device including an oscillator configured to output a first signal, and circuitry configured to count a cycle number of the first signal OSC. Before the oscillator outputs an N-th (N is an integer equal to or larger than 2) cycle of the first signal, the circuitry changes a count value of the cycle number of the first signal to N.

The present invention provides a fractional frequency divider, wherein the fractional frequency divider includes a plurality of registers, a counter, a control signal generator and a clock gating circuit. Regarding the plurality of registers, at least a portion of the registers are set to have values The counter is configured to sequentially generate a plurality of counter values, wherein the plurality of counter values correspond to the at least a portion of the registers, respectively, and the plurality of counter values are generated repeatedly The control signal generator is configured to generate a control signal based on the received counter value and the value of the corresponding register. The clock gating circuit is configured to refer to the control signal to mask or not mask an input clock signal to generate an output clock signal.