Cypress Semiconductor Corporation

National Semiconductor Corporation

Gabriel M Li

Hee Wong

Wong Hee

Greg J Richmond

Edward L Grivna

Paul H Scott

Thinh Tran

James R Hamstra

Chwei-po Chew

Dusan Vecera

Alan McLaughlin

Jun Li

Joseph Tzou

Ronald S Perloff

Ramanatha V Balakrishnan

Shahin Sharifzadeh

Bruce Barbara

Sangeeta Raman

K Nirmal Ratnakumar

Mohamed Sardi

Louise Y Yeung

Charles P Carinalli

Jose Arreola

Kenelm G D Murray

Johnson Tsai

In an embodiment, an apparatus includes a memory controller configured to control a plurality of daisy chained memory components connected over a daisy chained bus. The daisy chained bus includes a direct connection from the transmit interface of the memory controller to a receive interface of an initial memory component, and a daisy chain connection from a transmit interface of the initial memory component to a receive interface of a next memory component. A bus extends from a transmit interface of a last memory component directly to a receive interface of the memory controller.

Memory system and method

A serial interface device includes multiple serial link connections that receive at least address values and at least one error detection code (EDC) on different serial link connections, the EDC generated from at least the address values, the serial link connections for the address values and EDC operated separately from one another; and multiple output serial links, at least a first one of the output serial links outputting data values read from memory locations corresponding to the address values, and at least a second one of the output serial links different from and operated separately from the first one outputting EDC values generated for the data values read from the memory locations.

Serial interface devices, systems and methods

An output driver circuit can include at least a first driver transistor having a source-drain path coupled between a first power supply node and an output node. A first variable current supply can generate a current having at least one component that is inversely proportional to a power supply voltage. A first driver switch element can be coupled in series with the first variable current supply between a gate of the at least first driver transistor and a second power supply node.

Output buffer circuit

An apparatus having a plurality of power supply domains and a plurality of logic components. Each of the plurality of logic components residing within a different one of the plurality of power supply domains. Each of the plurality of logic components is configured to operate with a corresponding clock signal within a respective one of the plurality of power supply domains.

Circuit, system and method for multiplexing signals with reduced jitter

Disclosed is a circuit and method to program the starting phase of the spread spectrum of a clock output. The circuit includes a plurality of phase locked loop (PLL) circuits for generating a plurality of spread spectrum waveforms. The circuit also includes a spread control circuit for controlling each of the plurality of PLL circuits in accordance with a plurality of respective spread profiles. The spread profiles are configured to vary a starting phase of each spread spectrum waveform such that a total energy of each spread spectrum waveform is out of phase with other spread spectrum waveforms.

Method to program the starting phase of the spread spectrum

In an embodiment, an apparatus includes a memory controller configured to control first and second memory components. A point-to-point data bus configured to pass data between the memory controller and the memory components may include a direct connection from each memory component to the memory controller. A daisy chained address bus configured to pass commands between the memory controller and the memory components may include a direct connection from the first memory component to the memory controller and a daisy chain connection from the first memory component to the second memory component.

Circuit, system, and method for multiplexing signals with reduced jitter

A test circuit, system, and method are provided herein for testing one or more circuit components arranged upon a monolithic substrate. According to one embodiment, the system may include a test circuit and one or more circuit components, all of which are arranged upon the same monolithic substrate. In general, the test circuit may be configured for: (i) receiving an input signal at an input frequency, (ii) generating a test signal by modulating a phase of the input signal in accordance with a periodic signal, and (iii) supplying either the input signal or the test signal to the one or more integrated circuits, based on a control signal supplied to the test circuit. More specifically, the test circuit may be used to determine the jitter and/or duty cycle distortion (DCD) tolerance of any system component without changing the frequency of the clock signal supplied to the component or injecting noise into the clock recovery system.

Test circuit, system, and method for testing one or more circuit components arranged upon a common printed circuit board

A multiplexer circuit, system and method is provided herein for multiplexing signals with reduced jitter by eliminating all crosstalk and power supply noise injection within the multiplexer circuit. For example, crosstalk and supply noise injection may be eliminated by: (i) separating the multiplexing function into three separate logic gates and (ii) allowing only one switching input per logic gate. In some cases, jitter may be further reduced by distributing the logic gates across three distinct power domains. In other words, the logic gate inputs may be further isolated by gating each signal in its own power domain. In addition, the multiplexer circuit provides built in delay matching by utilizing three substantially identical logic gates.

A circuit and method are provided herein for monitoring the status of a clock signal. In general, the method may include supplying a pair of clock signals to a clock monitor circuit, which is configured for monitoring a status of one clock signal relative to the other. The status indicates whether the frequency of the one clock signal is faster, slower or substantially equal to the frequency of the other clock signal. Once determined, the status may be stored as a bit pattern within a status register, which is operatively coupled to the clock monitor circuit. This enables the status to be read by detecting a logic state of one or more bits within the status register.

Circuit and method for monitoring the status of a clock signal

Circuits and methods are provided herein for monitoring the integrity of a power supply, the circuits and methods providing additional resources/information for diagnosing a cause behind a reset signal, and in some cases, a reason behind a power failure. A first method described herein provides exemplary steps for monitoring a level of a power supply voltage supplied to one or more system components. A second method describes exemplary steps for monitoring an electrical connection between the power supply (or ground supply) and one or more supply pins. Each of the methods involves monitoring a state of one or more bits stored, e.g., within a status register. The methods may be used separately, or in conjunction with one another, for detecting the occurrence of a power abnormality.

Circuit and method for monitoring the integrity of a power supply

Disclosed is a circuit, comprising an input spread spectrum enable signal, a crystal oscillator, a first, second and third sampling flip-flop clocked by the crystal oscillator, configured to sample the input spread spectrum enable signal, and a plurality of control output signals derived from or provided directly from the sampling flip-flops. A method of operating the circuit is further described.

Apparatus and method for limiting the overshoot and undershoot when turning on the spread spectrum of a reference signal

A system and method are provided herein for monitoring the integrity of a power supply by monitoring a level of the power supply voltage supplied to one or more system components. The method, as described herein, includes setting a bit in a status register after the power supply level reaches a threshold level, and monitoring a state of the bit to determine if the power supply level has dropped below the threshold level. For example, the method may determine that the power supply level has dropped below the threshold level if the state of the bit changes from a set bit to a cleared bit. In addition, the system and method described herein may be used for detecting the occurrence of a power abnormality by providing additional resources/information about a power related event.

System and method for monitoring a power supply level

According to embodiments of the invention, temperature, current, or other physical quantities associated with an integrated circuit, which can also include a processor, may be converted to a digital signal, and that digital signal used to choose a corresponding frequency offset that is added to any pre-established overclocking frequency. Embodiments of the invention allow a user to specify a dynamic range between which the frequency offset is bounded during overclocking of the integrated circuit. The programmable lower limit specifies the frequency where the integrated circuit begins to overclock. The programmable upper limit specifies the maximum overclocking frequency that is allowed. Setting the lower limit to be equal to the upper limit forces overclocking to occur at only the specified value.

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San Francisco, CA, United States of America

Gabriel M Li