Atmel Corporation

Frederic Schumacher

Alain Vergnes

Eric Matulik

Guillaume Pean

Eric Matullk

A variable architecture for random number generators is disclosed. In some implementations, the architecture of a random number generator may be varied based on microcontroller-specific data stored on the microcontroller. For example, a random number generator module may be embedded in a microcontroller circuit. The random number generator module may be designed to receive input from data sources in the circuit that contain microcontroller-specific data (e.g., a unique chip identifier, data carried in fuse bits). In some implementations, the architecture of the random number generator module may be adjusted or varied based on the microcontroller-specific data.

Variable architecture for random number generators

True random number generation circuitry utilizes a pair of oscillators driving a pair of linear feedback shift registers, with their output being combined to generate random numbers. At least one of the oscillators is programmable with a variable frequency. One embodiment controls the variable frequency of oscillators with output from one or more sets of oscillators and linear feedback shift registers. In other embodiments, linear feedback shift register output is captured and used to control the frequency of oscillators.

True random number generator

A method for delaying a control signal, includes receiving a clock signal, determining a number of delay elements required to generate a first delay equal to a target amount of the period of the clock signal, receiving a data signal having an edge generated at the same time as an edge of the control signal, determining a fraction number equal to the number of delay elements needed to generate a second delay for the data signal or the control signal to align their edges, divided by the number of cascaded delay elements necessary to provide a delay equal to the target amount of the period of the clock signal, multiplied by the number of delay elements to generate the first delay, and delaying the control signal by the number of cascaded delay elements to realize said first delay altered by the fraction number of delay elements.

Circuits to delay a signal from a memory device

A circuit for providing a delayed clock signal to a synchronous memory controller controlling a synchronous memory device comprises logic delay circuitry for performing synchronous memory device read access, the logic delay circuitry generating delay interval information. A programmable delay line receives a clock signal and the delay interval information, the programmable delay line delaying the clock signal by the delay interval. A 2-input XOR gate receives both the clock signal and the output of the programmable delay line, an output of the XOR gate providing a delayed 2&#xd7; clock signal.

Clock circuitry for DDR-SDRAM memory controller

Various apparatus and methods include a clock circuit to receive a first clock signal to generate a second clock signal having a frequency different from a frequency of the first clock signal. A clock capturing circuit receives the second clock signal for determining a number of delay elements corresponding to an amount of a period of the second clock signal. A delay calculation circuit calculates an amount of time corresponding to the number of delay elements. And a delay circuit delays an input control signal by the amount of time provided by the delay calculation circuit.

Circuits to delay a signal from DDR-SDRAM memory device including an automatic phase error correction

A circuit for providing a delayed clock signal to a synchronous memory controller controlling a synchronous memory device comprises logic delay circuitry for performing synchronous memory device read access, the logic delay circuitry generating delay interval information. A programmable delay line receives a clock signal and the delay interval information, the programmable delay line delaying the clock signal by the delay interval. A 2-input XOR gate receives both the clock signal and the output of the programmable delay line, an output of the XOR gate providing a delayed 2X clock signal.

A serial network controller contains control logic to analyze and determine a duration of a proper frame time slot. A number of data fields in a transmission is ascertained from an identifier field supplied in a header field. The number of data fields plus a margin for data framing overhead is calculated to determine the frame time slot duration. A timer is programmed with the calculated frame time slot duration. The timer is clocked at each bit period of the transmission until the calculated duration of the frame time slot is reached. At the frame time slot value, a transmit ready flag is unmasked, allowing termination of the frame with a proper margin. By managing frame time slot calculation, timer operations, and interrupt handling, the control logic relieves a microprocessor core and other system resources from network timing details. The control logic frees system resources for other applications.

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Aix en Provence, France

Frederic Schumacher