Abstract: A circuit to synchronously select one of the multiple clocks is presented. In one embodiment the selection circuit consists of four main blocks. These are the stable selects block, the decoder block, the synchronous selects block, and the output block. The stable selects block takes select signals as inputs and outputs a signal indicating whether the selects are stable or not, in addition to producing select signals that are synchronous to the current selected clock. The decoder block, decodes the select signals if they are stable, otherwise it re-circulates the previous values of the decoded clock select signals. The stable decoded select signals are then passed on to the synchronous selects block. This block outputs select signals in synchrony with their respective clocks. The synchronous select signals along with the stable decoded signals are used in the output block along with the clocks themselves to generate the final output clock.

Abstract: Disclosed herein are a clock driver circuit and a method of routing clock interconnect lines, which control the lengths of adjacent interconnect lines and ununiformity of conductive line capacitance due to the intersection of interlayer interconnect lines, thereby reducing clock skews.

Abstract: A clock generation circuit includes a clock input circuit receiving complementary external clocks to generate an internal clock, a variable delay circuit delaying the internal clock to generate an internal operation clock, a replica circuit further delaying the internal operation clock by a predetermined time to generate a return clock, a phase comparator directly comparing the phase where potential levels of external clocks cross with the phase of the return clock, and a delay control circuit adjusting the delay amount of the variable delay circuit according to a phase comparison result of the phase comparator.

Abstract: A dual mode clock input buffer is disclosed. The input buffer includes a first portion for handling a single ended high voltage clock signal and a second portion for handling a differential low voltage clock signal.

Abstract: A clock buffer circuit (100) for generating buffered clock signals (CLKI and CLKI_) in response to an external clock signal (CLKX) is disclosed. A first buffer section (102) drives to a first output node (114) between high and low logic levels in reponse the CLKX signal. To reverse the adverse effects of noise on the falling edges of CLKX signal, a boost section (108) and clock generator (106) are provided. In response to low-to-high transitions at the first output node (114) the pulse generator (106) generates a pulse at a pulse output (126). In response to the pulse, the boost section (108) provides additional driving capability for further pulling the first output node (114) to the high logic level. The first output node provides the CLKI_ signal. A second buffer circuit (104) provides the CLKI signal in response to the CLKI_ signal. An enabling section (110) is provided for enabling, or alternatively, disabling the preferred embodiment (100).

Abstract: In a clock modulator for modulating a basic clock signal to form a system clock signal for a digital system containing at least one microprocessor and/or other digital module, the system clock signal generating an interference spectrum with interference spikes in the digital system, it is provided that the clock modulator (11) can be adapted as a function of the interference spectrum of the system clock signal (4) in the digital system (5) in such a way that the amplitudes of the interference spikes are reduced.

Abstract: A clock generation circuit including a multiphase clock generation circuit for generating multiphase clocks of a predetermined frequency, pulse generation circuits for generating a plurality of non-overlap pulses by using at least a part of the multiphase clocks of the multiphase clock generation circuit, and a circuit for obtaining an OR of the plurality of non-overlap pulses of the pulse generation circuits and thereby generating a clock not having a simple whole multiple ratio relationship with respect to a frequency of the multiphase clocks or a clock having a higher frequency without causing an increase of power consumption and an increase of chip area.

Abstract: A fixed frequency clock generator generates and outputs a fixed frequency clock by using a number of fixed delay units and a number of inverters that both are connected in series alternately and evenly. More particularly, the fixed delay unit involves two fixed current sources and two controlling switchers, plus an inverter that controls a charging and a discharging of a capacitor. Then the electric potential of the capacitor and a stable voltage source respectively send the current to the comparator. The time of charging and discharging of the capacitor is fixed, therefore the time of the electric potential of the capacitor is fixed for reach to the fixed voltage source, and the sequence of the output signal of the comparator is also fixed. In the above description, the fixed delay unit generates the fixed frequency.

Abstract: A phase stable clock circuit includes a phase gate having track-and-hold (T/H) circuits with each T/H circuit receiving a phase shifted continuous sinusoidal signal of predetermined phase and a control input signal to hold, at a selected time during the signal epoch of the respective sinusoidal signals, phase values of the sinusoidal signals. The respective phase values are coupled to an infinite track-and-hold circuit to generate replicas of the phase values. The phase values and the replica phase values are coupled to respective multiplexers that selectively couple the phase values to multipliers during a first time period and replica phase values during a second time period. The output of each multiplexer is coupled to a multiplier that receives one of the phase shifted continuous sinusoidal signals. The output of the multipliers are summed in a summing circuit to generate an output signal with a predetermined stable startup phase relative to the transition.

Abstract: A digital delay interpolator adapted to receive a first clock signal and a second clock signal, the second clock signal having a transition at a time that is delayed with respect to the time of a transition of the first clock signal, and to provide an output clock signal having a transition at a time intermediate the time of the transition of the first clock signal and the time of the transition of the second clock signal. The interpolator includes a first plurality of selectively enabled delay circuits and a second plurality of selectively enabled delay circuits, the first plurality of delay circuits having an input port being adapted to receive the first clock signal, and the second plurality of delay circuits having an input port being adapted to receive the second clock signal. The first plurality of delay circuits and the second plurality of delay circuits have outputs connected together to form the output of the digital delay interpolator.

Abstract: A timing circuit for ATE generates an output clock from an input clock and controls output pulse width. The timing circuit includes a differential driver having an input that receives the input clock, and having inverting and non-inverting outputs. The inverting output is coupled to a first phase-locked loop, and the non-inverting output is coupled to a second phase-locked loop. The first and second phase-locked loops respectively generate first and second clocks in response to respective rising and falling edges of the input clock. A combiner circuit converts the first and second clocks into narrow pulse trains, and the pulse trains respectively operate SET and RESET inputs of a SET/RESET flip-flop. The SET/RESET flip-flop generates an output clock having rising edges responsive to rising edges of the input clock, and falling edges responsive to falling edges of the input clock.

Abstract: A clock synchronizer circuit provides an internal clock signal for an integrated circuit that is synchronized to an external system clock signal, such that the internal clock integrated is aligned with and has minimal skew from the external system clock signal. The clock synchronizer circuit allows synchronizing of internal clocks of an integrated circuit with the external system clock having a period &tgr;ck less than the cumulative delay of internal receiving and distribution circuits of the integrated circuit.

Abstract: A programmable delay circuit employs a relatively slow conventional silicon emitter-coupled transistor pair and a relatively fast silicon/germanium heterojunction emitter-coupled transistor pair. The bases of both transistor pairs are driven by an input signal to be delayed. The collectors of transistors of both pairs are linked to a voltage source through a pair of load resistors, with an output signal appearing across the collectors of both transistor pairs. A current source draws complementary adjustable load currents through the two transistor pairs. Although the sum of the two load currents is a constant, the relative amount of load current drawn though the two transistor pairs is adjustable.

Abstract: The present invention provides a clocked comparator which extends the time period before an input signal is measured to include most of the clock cycle, thereby increasing the amount of time available for the input signal to achieve a “steady-state” condition. After the input signal achieves a “steady-state” condition the comparator compares the input signal against a reference voltage and a decision register latches the comparator output. The decision signal may then be further latched to be made available for external circuitry in the subsequent clock cycle. A multi-phase programmable signal generator is connected to the clocked generator for generating a plurality of timing signals. The multi-phase programmable signal generator employs a plurality of single bit registers interconnected in series to form a shift register. Output signals generated by the programmable signal generator are used to drive the switches and register clocks of the clocked comparator.

Abstract: A method of generating a symmetrical output signal with a 50% duty cycle. The symmetrical output signal is generated without the need for the input signal to be at twice the frequency of the output signal. By utilizing the differential output of a circuit and cross-coupling this to the inputs of comparators a series of outputs are obtained. These outputs are then used to control a latch device by utilizing only a single edge. Because only a single edge is used to control the low to high and high to low transition, the delay is a fixed constant and the resulting output is a symmetrical output signal with a 50% duty cycle.

Abstract: A burst-mode capable RAM chip includes a timing circuit for clocking a burst counter during a burst transfer. In response to an input indicating the beginning of the burst transfer, the timing circuit generates a first signal that loads the initial address of the burst transfer into the latches of a burst counter. Then, the timing circuit generates a second signal to increment the burst counter to the second address in the burst transfer after the load of the initial address has successfully completed but prior to the second clock cycle. Finally, the timing circuit generates subsequent signals to increment the burst counter through the remaining addresses of the burst transfer. Each of the subsequent signals is generated in response to an input from the system clock.

Abstract: A clock switch controller has a clock status register which stores current clock data which identifies which of two or more clock signal sources is a current clock signal source currently in use as a system clock signal source. State machine logic of the controller automatically switches, in response to a clock switch signal, the system clock signal source from the current clock signal source to a new clock signal source of the two or more clock signal sources.

Abstract: A synchronous integrated circuit clock circuit is disclosed. The clock circuit (200) receives a system clock (CLKX) and in response thereto, generates an internal clock (CLKI) that is shifted forward in phase with respect to the system clock signal (CLKX). The amount by which the internal clock (CLKI) is shifted remains relatively constant over a range of system clock (CLKX) frequencies. The clock circuit (200) includes a measuring section (202) that measures the period of the system clock (CLKX), a logic section (204) that determines a delay value based upon the duration of the system clock (CLKX) period, and a generation section (206), that provides the internal clock signal (CLKI).

Abstract: A first clock and a second clock are provided. The first and second clocks operate at first and second frequencies, respectively. The phase difference between the first clock and the second clock is accumulated to generate a control signal. In response to the control signal, the phase of the second clock is controlled so as to synchronize with the first clock. Preferably, the phase of the second clock is shifted from the normal timing, when the accumulated value reaches a cycle of the first clock.

Abstract: Integrated circuits having cooperative ring oscillator clock circuits therein include a plurality of synchronous and asynchronous active devices on the substrate and a plurality of "cooperative" ring oscillators (CRO) electrically coupled in parallel at respective clock nodes, interspersed on the substrate as a mesh, for example. The ring oscillators, which may have a predetermined number of stages but possibly different size in terms of clock driving capability, are preferably interspersed among the synchronous active devices on the surface of the substrate to provide a "local" clock signal which is constrained in terms of skew and jitter by the presence of the other parallel-connected ring oscillators at other locations on the substrate. Multiple replications of a ring-oscillator containing three serially connected inverters may result in the formation of a two-dimensional hexagonal network of clock nodes of different phases (e.g., .phi..sub.1, .phi..sub.2 and .phi..sub.3).

Abstract: A data processing apparatus functions as a timer or counter by counting clock pulses of a system clock signal to generate a timing signal. The system clock signal is generated as one of either a first or a second basic clock signal generated by two respective oscillators. Even if the second basic clock signal which has a lower frequency fluctuates, the data processing apparatus can accurately generate a pulse signal having a desired period. When the first basic clock signal is selected as the system clock signal, the second basic clock signal is measured with the system clock signal. When the second basic clock signal is selected as the system clock signal, a numerical value up to which the clock pulses of the system clock signal are counted is corrected on the basis of the measured second basic clock signal.

Abstract: A timer circuit for providing output pulses of an adjustable duration based upon stored decode parameters. The circuit has a timer element which generates a periodic timing signal. Preferably the frequency of the periodic timing signal is also adjustable. A frequency divider is clocked by the timing signal and provides a plurality of frequency divided outputs. A decode circuit combines selected ones of the frequency divided outputs based upon decode parameters and generates a timer circuit output pulse having a duration determined by the frequency divided outputs selected by the decode parameters. The decode parameters are stored in a non-volatile data storage unit so that the timer output pulse will remain the same after power interruption.

Abstract: A delay lock loop circuit for a semiconductor memory element generates a synchronized internal clock signal by receiving an external clock signal as an input. The delay lock loop circuit generates a clock signal having a very fast period in order to enhance speed of data being synchronized by a clock signal. The delay lock loop (DLL) circuit includes: a N frequency dividing means which respectively receives the external signal having the frequency f, and generates a signal having a frequency f/N; a N delay lock loop means which respectively receives the signal having the frequency f/N generated from the N frequency dividing means, and maintains it for a predetermined period; and a merging means which performs a logic operation on each output pulse signal generated from the N delay lock loop means, and generates the synchronised internal signal.

Abstract: A semiconductor memory device including an operation control circuit for selecting between a single data rate (SDR) mode and a double data rate (DDR) mode. The operation control circuit includes a mode selector for generating a master signal which selects between the SDR and the DDR mode. The operation control circuit also includes a shift register, a repeater, and a pulse generator. When the SDR mode is selected, the shift register generates an output clock signal which changes states every period of the input clock signal. When the DDR mode is selected, the repeater generates an output clock signal which changes states with every state change of the input clock signal. Productivity efficiency is enhanced and production costs are reduced by providing both the SDR and the DDR mode circuitry and the operation control circuit on a single chip.

Abstract: A pulse generating circuit which has a first and a second delay circuit selectively operable as a delay circuit or a resetting circuit. The delay circuits each has a discharge transistor and a charge transistor in order to fix the potential on its associated node rapidly when operating as a resetting circuit. Even when short pulses are continuously input as an input signal by accident, the circuitry surely outputs a single pulse transitioning at the same time as the first change in the input signal and having a desired duration since the last change in the input signal.

Abstract: A power management system is disclosed. The system includes an oscillator interface for use in a power management system, a power recycle circuit for use in a power management system, a pad clock and self test for use in a power management system, a clock enable circuit for use in a power management system, a power level detect circuit for use in a power management system, an internal source clock generation circuit for use in a power management system, and a power-save mode change detection circuit for use in a power management system. The oscillator interface includes an interface circuit for interfacing with an external oscillator used as a source of oscillations. A clock stabilization filter masks out spurious crystal frequencies in the oscillations during start-up of the power management system following an enabling of a feedback loop. The clock stabilization filter has circuitry which provides that the oscillations will start with a rising transition after filtering.

Abstract: A system of spreading the energy of higher harmonic frequencies in digital circuits to lower the interference to bandpass receivers is disclosed. A set of passive, impedance-regulated circuits, preferably housed in a standard enclosure, comprises a power restoring unit, a modulating signal generator, an internal oscillator and an impedance spreading unit. The circuits are equivalent to passive resonators such as crystal resonators used in standard oscillators. Any existing standard oscillator that uses common crystal resonators can be transformed into a spectrum-spread oscillator by replacing the crystal resonator with the disclosed circuit, whereby a tightly controlled small frequency spreading occurs in the fundamental clock frequency. Further an active oscillator is disclosed wherein a spreading circuit spreads the frequency of the clock signal originally generated by the oscillator based on a sequence of processing the original clock signal.

Abstract: The present invention encompasses the use of multiple feedback paths in a clock source for an integrated circuit device to maintain phase lock to an external clock. It is further contemplated by the present invention that feedback paths are provided from the internal clock distribution path and from a matching path that approximates the delay of the clock distribution path. The matching path may comprise a delay locked loop. Feedback from the clock distribution path is used in normal operation and feedback from the matching path is used when the internal clock distribution path is disabled. The clock source of the present invention also may implement power management functions.

Abstract: A PLL based clock generation circuit that enables processor execution during phase locking is provided. A PLL (310) generates a PLL clock output to a divider (330), which divides the PLL clock at a system clock output. PLL (310) outputs a frequency lock signal upon acquiring a desired output frequency that initiates a counter (320) and enables execution in a CPU (350) being clocked by the system clock. CPU (350) is thereby enabled to execute during phase locking at a divided frequency without risk of frequency overshoot induced failures. A phase lock signal, indicating PLL (310) has achieved phase lock, output by counter (320) is logically combined (340) with a signal output from CPU (350) requesting maximum frequency operation. The combined signal selects divider (330) to enable a maximum frequency system clock, thereby enabling CPU (350) to execute at maximum frequency when the PLL (310) is safely phase locked.

Abstract: A clock generator serves to generate a stable frequency system clock for a clock-controlled electronic device. To ensure that the system clock causes only little electromagnetic interference to nearby electronic equipment, the system clock is modulated with respect to a reference clock by means of a phase modulator controlled by a random signal source which is noise colored by means of a weighting device.

Abstract: The present invention is a clock generator circuit using semiconductor integrated circuits and which has an input logic circuit to which an external clock signal is supplied; a delaying element chain in which a plurality of delay elements connected to the input logic circuit are serially connected together; a plurality of delay element selectors connected to each of the plurality of delay elements, respectively; a loop closing circuit connected to the delay element connected to a specific delay element selector which to a state indicating a selected status and to the input logic circuit, for forming a closed loop between the delay element chain and the input logic circuit; and an external output connected to the input logic circuit.

Abstract: A fully digital clock multiplier capable of generating any N/M multiple of an input clock frequency with a precise duty cycle is provided. The input clock signal is divided by M to create a divided clock signal. The propagation of the input clock signal along a delay cell string during a half cycle of the divided clock signal is then measured. The measured propagation is then scaled by a factor N to select an appropriate delay cell string length within a ring oscillator for generating an output signal.

Abstract: A clock driver circuit comprises a first and a second clock driver 15a and 15b. In each of these clock drivers, a plurality of main drivers 19(1) through 19(n) have their input nodes and output nodes connected respectively to a first and a second common line 18 and 21. The second common line 21 is connected to a plurality of clock signal supply lines 20(1) through 20(m) which in turn are connected to the clock input nodes of second macro cells 16 each requiring a clock signal. In a test mode, the first and second common lines 18a and 21a of the first clock driver 15a and the first and second common lines 18b and 21b of the second clock driver 15b are electrically connected by first and second connection means 22 and 24, respectively. Thus, a clock driver circuit is provided that offers high driving ability with negligible clock skews in both normal mode and test mode.

Abstract: An internal clock generator is provided in which a clock having the smaller difference between the cycle of the clock and the delay time of a combinational circuit is generated. The combinational circuit included in a circuit to which the clock is supplied includes five signal processing portions which can become critical paths. Dummy signal processing portions are circuits corresponding to the signal processing portions, respectively. A clock which includes, in a cycle, the maximum value of the delays between the inputs and outputs of the dummy signal processing portions is generated. Consequently, if the critical path of a circuit for inputting the clock is changed and the delay time of the combinational circuit is increased or decreased, the cycle of the clock is increased or decreased accordingly. As a result, the difference between the cycle of the clock and the delay time of the combinational circuit is reduced so that the operation of the circuit is performed at higher speed.

Abstract: A timer circuit for providing output pulses of an adjustable duration based upon stored decode parameters. The circuit has a timer element which generates a periodic timing signal. Preferably the frequency of the periodic timing signal is also adjustable. A frequency divider is clocked by the timing signal and provides a plurality of frequency divided outputs. A decode circuit combines selected ones of the frequency divided outputs based upon decode parameters and generates a timer circuit output pulse having a duration determined by the frequency divided outputs selected by the decode parameters. The decode parameters are stored in a non-volatile data storage unit so that the timer output pulse will remain the same after power interruption.

Abstract: A timing generator circuit according to the present invention receives rate signal pulses and delay assignment data composed of rate number data and clock number data, and outputs timing signals delayed from the input timing of the rate signal pulses by intervals corresponding to the delay assignment data. The timing generator circuit comprises a counter for counting clock signals, which is reset by means of the rate signal pulses; a shift register for sequentially shifting the delay assignment data or data corresponding to the delay assignment data by means of the rate signal pulses; a coincidence detector for detecting data corresponding to predetermined rate number data from among output data from a stage of the shift register, and outputting pulses when clock number data contained in the output data coincide with count values of the counter; and a multiplexer for multiplexing the pulses outputted from the coincidence detector section and outputting the result as a timing signal.

Abstract: A timer circuit for providing output pulses of an adjustable duration based upon stored decode parameters. The circuit has a timer element which generates a periodic timing signal. Preferably the frequency of the periodic timing signal is also adjustable. A frequency divider is clocked by the timing signal and provides a plurality of frequency divided outputs. A decode circuit combines selected ones of the frequency divided outputs based upon decode parameters and generates a timer circuit output pulse having a duration determined by the frequency divided outputs selected by the decode parameters. The decode parameters are stored in a non-volatile data storage unit so that the timer output pulse will remain the same after power interruption.

Abstract: A clock enabling circuit that generates an output clock signal such that when the enable output signal changes to a logical false, the output clock signal returns to its steady-state value in a manner that does not produce any glitches, and preserves the duty cycle of the input clock. The circuit comprises a first D flip-flop that is positive-edge triggered, a second D flip-flop that is negative-edge triggered, and a two-input AND gate. The first flip-flop has the D input connected to a constant positive voltage, the positive-edge triggered clock input connected to the input clock signal, the Q output connected to the AND gate, and the Q-complement output connected to the asynchronous reset of the second flip-flop. The second flip-flop has the D input connected to the enable output signal, the negative-edge triggered clock input connected to the input clock signal, the Q output connected to the asynchronous reset of the first flip-flop, and the Q-complement output connected to the AND gate.

Abstract: A clock signal generator for an IC tester has a clock control circuit provided between a jitter reduction circuit and an IC device to be tested. The clock control circuit inhibit the clock signal from reaching the IC device for a time period required for a clock signal changes to a new frequency. The clock signal generator includes: a timing generator for generating clock signals and timing signals based on a test program, a pattern generator which receives the timing signals from the timing generator for producing test pattern signals to be supplied to the IC device based on the test program, a jitter reduction circuit for receiving a clock signal from the timing generator and for reducing a jitter of the clock signal, and a clock control circuit for inhibiting the clock signal from the jitter reduction circuit from being supplied to the IC device for a inhibit period determined by the test program when a frequency of the clock signal has been changed.

Abstract: In a clock signal control circuit of a semiconductor device, a first clock signal is externally supplied to a first terminal of the semiconductor device in an external clock signal mode. In an external element using mode, a second clock signal is generated on said first terminal by a clocked inverter and a self-biasing resistor composed of a P-channel MOS transistor and N-channel MOS transistor, using elements externally connected between the first terminal and a second terminal of the semiconductor device. The clock signal on said second terminal in the external clock signal mode or the external element using mode is supplied to the internal circuit of the semiconductor device using a Schnmitt trigger type of logic gate. In the external clock signal mode, the clocked inverter and the self-biasing resistor are turned off such that the generation of the second clock signal is inhibited. Further, in a clock signal stop mode, the supply of the clock signal is inhibited.

Abstract: A clock generator circuit for providing a clock signal to a dual-edged D-type flip-flop, enabling the flip-flop to be dual edged, single edged, or to enable a user to provide clock edge selection, asynchronous clocking, clock enabling, or a mixture of different type clock signals. The clock generator circuit includes inputs receiving first and second enables signals and a clock signal. The clock generator circuit further includes circuitry to provides an output clock signal which transitions when a rising edge of a pulse of the clock signal is received when the first clock signal is enabled, or if a falling edge of a pulse of the clock signal is received when the second clock signal is enabled.

Abstract: A timing generator which receives a rate signal and generates an output signal based on the rate signal, and comprises at least two delay lines for causing delays in the rate signal, a formatter for receiving signals from the delay lines and for determining the rise and fall of an output signal according to such signals from the delay lines, and for generating an output signal, memories for storing delay time data from the delay lines, and a data selector for taking the delay time data from the memories and to switch the delay time data, whereby accurate timing signals are generated utilizing short skew adjustment time.

Abstract: It is an object of the present invention to restrict EMI radiation at a specific frequency by inserting a delay time that is effective for that frequency. The feature of the present invention is to provide a delay generator that can selectively alter delay times. The delay generator comprises: delay means, which is connected to a plurality of data input lines, and which has a plurality of delay paths for the generation of a plurality of alternative delay times; a register for storing a digital value of pre-determined bit; and selection means for selecting one of the delay paths in consonance with the digital value and for providing the selected delay path for the signal lines.

Abstract: An edge-trigger pulse generator that is suitable for use in a signal generator is disclosed, including positive and negative logic embodiments. The positive logic embodiment includes: a first time-delay circuit for delaying and inverting an input pulse; a second time-delay circuit for broadening the width of the input pulse; a NAND gate for receiving outputs of the first time-delay circuit and the second time-delay circuit, and performing a NAND logical operation for the outputs; and an inverter for receiving and inverting output of the NAND gate, so that the width of an pulse output from the edge-trigger pulse generator can be determined merely by the edge-trigger pulse generator while the width of the input pulse is not wider than a predetermined width. The negative logic embodiment replaces the NAND gate with NOR gate and has a second time-delay circuit that is different from the second time-delay circuit of the first embodiment.

Abstract: A clock signal is distributed over a circuit board and across a connector as a sine wave. A circuit located near the clocked circuitry converts the sine wave into a same frequency square wave for use by the clocked circuitry. The output stage of the converter circuitry provides a high output level to drive CMOS circuitry. The output transistor is pulled up to 5 volts, but the preceding transistors are pulled up to 6.3 volts so that the base to emitter drops are compensated.

Abstract: A variable pulse width generator comprised of apparatus for receiving a clock signal, apparatus for terminating an output pulse from a leading edge of the clock signal, and apparatus for initiating another output pulse following the terminated output pulse from the leading edge of the clock signal and after a first delay, whereby successive output pulses are initiated and terminated that are related to the leading edge of the clock signal, and thus are related to the frequency but not the pulse Width of the clock signal.

Abstract: A timer comprised of first and second gated SR (set-reset) latches each including two pair (S1, S2 and R1, R2) of inputs and a pair of outputs (Q, QN), the Q output of the first latch being connected to the R2 input of the second latch, and the QN output of the first latch being connected to the S2 input of the second latch, the Q output of the second latch being connected to the S2 input of the first latch, and the QN output of the second latch being connected to the R2 input of the first latch, apparatus for applying a delayed representation of a first pulse signal to the S1 input of the first latch and apparatus for applying a delayed representation of a second pulse signal to the R1 input of the first latch, apparatus for applying an inverted representation of the pulse signal to the S1 input of the second latch and apparatus for applying an inverted representation of the second pulse signal to the R1 input of the second latch, whereby timed output signals representing a differential between leading edges

Abstract: A clock system includes internal monitor circuitry such that the clock system is testable in a secure environment. In particular, the clock system includes a plurality of separately enableable clock generator circuit modules. Each of the clock generator circuit modules generates a separate clock signal when enabled. Combining circuitry receives the separate clock signals from those clock generator circuit modules which are enabled and derives a derived clock signal therefrom. Monitor circuitry receives the derived clock signal, detects whether there are transitions in the derived clock signal, and provides a monitor indication of a result of the detection. Thus, the clock system can be tested without providing the separate clock signals outside the clock system. Preferably, the clock system also includes a programmable clock control register that holds clock control data, the clock control data determining which of the clock generator circuit modules are enabled.

Abstract: A timing adjustment circuit consists of a delay circuit made from n delay elements (n is an integer of 2 or more) connected in series, with which an input signal p0 is delayed in succession by each delay element, in order to generate respective delay-signals p1, . . . , pn, and a selection circuit with which any one of input signals p0 and aforementioned respective delay signals p1, . . . , pn are selected by n+1 number of selection signals s0, . . . , sn. The selection circuit comprises a selection-signal generation circuit, a selection gate circuit, a selection-signal holding circuit and a delay-signal holding circuit. The selection-signal generation circuit generates selection signals s0, . . . , sn before input signal p0 is input. The selection-signal holding circuit holds selection-signals s0, . . . , sn from the selection-signal generation circuit until the active edge of p0, . . . , pn reaches each selection gate. The delay-signal holding circuit comprises n delay-signal holding elements.

Abstract: A timer circuit for providing output pulses of an adjustable duration based upon stored decode parameters. The circuit has a timer element which generates a periodic timing signal. Preferably the frequency of the periodic timing signal is also adjustable. A frequency divider is clocked by the timing signal and provides a plurality of frequency divided outputs. A decode circuit combines selected ones of the frequency divided outputs based upon decode parameters and generates a timer circuit output pulse having a duration determined by the frequency divided outputs selected by the decode parameters. The decode parameters are stored in a non-volatile data storage unit so that the timer output pulse will remain the same after power interruption.