Standard Microsystems Corporation

Microchip Technology Inc.

Smsc Holdings Sarl

Eileen Marando

Robert W Schoepflin

Richard Wahler

Alan David Berenbaum

Arun Krishnan

Steven Burstein

Jay D Popper

Richard E Wahler

Wayne A Miller, Jr

Randy Goldberg

A device with boot code, first mutable code stored in non-volatile memory, a first owner information stored in the non-volatile memory, and an SRAM with an SRAM physically unclonable function (SRAM PUF) region. Boot code may generate a first unique private key based on both the first owner information and a portion of the SRAM PUF region, wherein the first unique private key may not be directly accessible by the first mutable code; generate a first unique private keycode corresponding to the first unique private key; and provide the first mutable code with the first unique private keycode corresponding to the first unique private key. First mutable code may use the first unique private keycode to cause data to be signed with the first unique private key and generate a first unique mutable code private key based on at least a portion of the SRAM PUF region.

SRAM physically unclonable function (PUF) memory for generating keys based on device owner

A device with one-time-programmable (OTP) memory, boot code, volatile memory, and non-volatile memory. Boot code may use information in OTP to authenticate code of an implicit owner of the electronic device; receive a first create owner container request; create a first owner container comprising a first signed data image; store the first owner container; and use the first signed data image to authenticate first executable code associated with the first owner. Boot code may transfer ownership from the first owner to a second owner, including authenticating a signed transfer of ownership command using a key stored in the first owner container and creating a second owner container comprising a second signed data image associated with the second owner; storing the second owner container; revoking the first owner container; and using the second signed data image to authenticate second executable code associated with the second owner of the electronic device.

Managing ownership of an electronic device

The present disclosure provides an improved point-to-point serial peripheral interface, a system comprising an improved point-to-point serial peripheral interface, and a method for use in a system comprising an improved point-to-point serial peripheral interface. A master comprises a SPI initiating port. Each slave comprises at least one SPI receiving port and at least one SPI forwarding port. The master provides a set of SPI signals to the SPI receiving port of the first slave in the chain, and the entire SPI signals are forwarded via the SPI forwarding port of each of the slaves until the SPI transaction reaches a target slave, which is identified by an in-band device addressing mechanism.

Point-to-point serial peripheral interface for data communication between devices configured in a daisy-chain

A system may include a PWM generator and control logic. The PWM generator is configured to generate a PWM signal having a duty cycle dependent on a duty cycle value generated by the control logic. The control logic is configured to generate the duty cycle value to have a piecewise linear relationship with temperature such that at least two of a plurality of linear segments defined by the piecewise linear relationship have different slopes. In some embodiments, the piecewise linear relationship may be continuous.

Generating a PWM signal dependent on a duty cycle having a piecewise linear relationship with temperature

Temperature readings obtained within a computer system from the location of monitored circuit elements may be oversampled at least three times, and a median average of the three parameter readings rather than the arithmetic mean may be used for controlling a device, e.g. a fan, configured to regulate the environmental parameter, e.g. temperature, a the location of the monitored circuit elements. For example, when a CPU temperature reading is requested by the system comprising the CPU, a thermal monitoring system may acquire at least three consecutive temperature readings of the CPU, discard the highest temperature reading and the lowest temperature reading, and return the median reading to be used in controlling a fan configured to regulate temperature at the location of the CPU, resulting in more accurate temperature readings and more accurate fan control. In various implementations, more than three readings may be considered at a time, and running averages based on median values may be computed in a variety of ways to obtain a temperature control value to control the fan.

Processor temperature measurement through median sampling

An embedded controller capable of providing direct memory access (DMA) to memory for a host. The controller may include a processor, a memory medium, and an interface coupled to the memory medium. The interface may be configured to couple to a host and receive a DMA request. The DMA request may include a request to read data from a memory location in the memory medium or a request to write data to a memory location in the memory medium. The DMA request may include a relative memory address. The interface may be configured to translate the relative memory address into a first address of the memory medium. Accordingly, the interface may perform operations according to the DMA request using the first address of the memory medium. The processor may be configured to operate according to data stored in the memory medium.

External direct memory access of embedded controller memory

A method and apparatus for operating a portable computer configured for docking to a docking station is disclosed. In one embodiment, a portable computer system includes a docking interface having a bus switch and a bus monitoring circuit, and a bus coupled to the docking interface. With the computer coupled to a docking station, the bus switch, when closed, may couple the bus to a peripheral interface in the docking station. The bus switch may close responsive to docking, thereby completing the electrical coupling of the bus to the peripheral interface in the docking station. The portable computer being docked to the docking station, the bus monitoring circuit may monitor the bus cycles occurring on the bus and identify trusted read and/or write cycles. During trusted bus cycles the monitoring circuit may operate to open the bus switch thereby preventing information transmitted during the trusted cycles to be accessible outside of the portable computer system, even with the portable computer system remaining docked to the docking station. The monitoring circuit may also operate to close the bus switch in response to a currently occurring trusted bus cycle being interrupted, aborted and/or completed.

Trusted LPC docking interface for docking notebook computers to a docking station

A control signal value, such as a duty cycle value for a Pulse Width Modulated (PWM) generator output, for controlling and/or powering a fan may be calculated using an autofan function configured with dynamic hysteresis control (DHC). As part of the DHC, the PWM duty cycle value may be determined by applying a hysteresis component at every point of the autofan function relating the PWM duty cycle to temperature. The PWM duty cycle value may be computed based on two functions, each function relating the PWM duty cycle to temperature, the first function applied when the temperature is increasing, and the second function applied when the temperature is decreasing. When a newly computed PWM duty cycle value falls within a range of duty cycle values defined by the hysteresis value, the current duty cycle of the PWM generator output may remain unchanged, minimizing noise resulting from the fan changing speed.

Dynamic hysteresis for autofan control

A fan control system in which a sensor selection block having a number of sensor inputs may be combined with an autofan block having a number of zone inputs, where the number of sensor inputs is greater than the number of zone inputs. Each one of the sensor inputs of the sensor selection block may have a corresponding sensor parameter input. The sensor selection block may be configured to map a subset of the sensor inputs with corresponding sensor parameter inputs to the autofan block. Each zone input and corresponding zone parameter input of the autofan block may receive a corresponding one of the subset of the sensor inputs with corresponding sensor parameter inputs, respectively. The autofan block may have a number of pulse width modulated (PWM) outputs that may be calculated according to the autofan block zone inputs and zone parameter inputs.

Mapping a plurality of sensors to respective zones in a fan control system

A system and method for controlling a fan is disclosed. A single control signal value for controlling the fan, such as a single PWM duty cycle value for a corresponding PWM generator output powering the fan, may be calculated by combining sensor data from two or more temperature zones. In one embodiment, the single PWM duty cycle value may be determined based on the temperature in a first zone, for example the CPU, with an additional factor based on the temperature in a second zone, for example the ambient temperature of a PC enclosure. In one embodiment, the final single PWM value is determined by adding an offset value to a PWM value calculated based on the current temperature of the first zone, where the offset value is obtained by calculating a first &#x394;PWM factor for the first zone, and using the first &#x394;PWM factor, in conjunction with a scaling factor, to weight a second &#x394;PWM factor calculated for the second zone.

Autofan combination of zones

Piecewise linear control of the duty cycle of a pulse width modulated signal

A system may include control logic and a PWM generator configured to generate a PWM (Pulse Width Modulated) signal. The PWM generator is configured to generate the duty cycle of the PWM signal dependent on a duty cycle value generated by the control logic. The control logic stores an inverse focal point value and is configured to generate the duty cycle value by processing the inverse focal point value and a temperature value indicating a current temperature according to the equation of a parabola.

Parabolic control of the duty cycle of a pulse width modulated signal

A system may include a tachometer reading unit and a PWM (Pulse Width Modulated) signal generator configured to generate a PWM signal. The tachometer reading unit may be configured to obtain a tachometer reading from a tachometer signal generated by a device powered by the PWM signal. The tachometer reading unit includes a register configured to store a value indicative of a maximum stretching duration. The tachometer reading unit is configured to update the register in response to receiving a new value of the maximum stretching duration. The tachometer reading unit may be configured to control the PWM signal generator to stretch a pulse in the PWM signal and to not stretch the pulse longer than the maximum stretching duration indicated by the register. The tachometer reading unit is configured to obtain the tachometer reading during the stretched pulse in the PWM signal.

Programmable PWM stretching for tachometer measurement

A system and method for increasing resolution of pulse width modulated (PWM) signal duty cycle calculations in a fan speed control system operating to control rotational speed of at least one fan. The method may comprise obtaining a temperature reading from a first temperature sensor in the fan speed control system during a first time period. The temperature reading has resolution of a first number of bits. A portion of the first number of bits is selected for calculating a PWM signal duty cycle with the resolution of the first number of bits in the temperature reading using only the portion of the first number of bits and zone parameters associated with the first temperature sensor. The PWM signal duty cycle may then be converted into a PWM signal that may be provided to the at least one fan.

Growing community of inventors

Bellmore, NY, United States of America

Eileen Marando