Abstract: A method of accessing electronic memory is provided in electronic circuits where it is desired to lower power consumption and hence there is no active oscillator at the time when access to data within the electronic memory is required. The invention provides a method therefore for accessing the electronic memory from a controller, which generates its own clock signals from a data, communications bus electrically coupled to the controller. Advantageously the method allows for memory access to be continued in integrated circuits where a subset of circuits are powered down to reduce power consumption, and one of the subset of circuits is an oscillator.

Abstract: Methods and apparatus for implementing and operating pulse width modulation based LED dimmer controllers are described. A synchronization protocol is used to allow control information for the dimmer operations to be transferred to the PWM dimmer control clock domain from an external clock domain, such that visual artifacts are prevented when the control information is updated. Control information may be transferred to the LED dimmer controller via an I2C serial bus, and the synchronization protocol waits for an I2C STOP condition before updating control information across clock domain boundaries. The leading and trailing edges of an asserted group dimmer control signal are generated such that the active portion of the group dimmer control signal overlaps the active portion of individual LED pulse width modulated control signals. In this way, the pulse width modulation of the individual LED control signals is not cut off, or reduced in width by the group dimmer signal.

Abstract: A method of accessing electronic memory is provided in electronic circuits where it is desired to lower power consumption and hence there is no active oscillator at the time when access to data within the electronic memory is required. The invention provides a method therefore for accessing the electronic memory from a controller, which generates its own clock signals from a data, communications bus electrically coupled to the controller. Advantageously the method allows for memory access to be continued in integrated circuits where a subset of circuits are powered down to reduce power consumption, and one of the subset of circuits is an oscillator.

Abstract: Methods and apparatus for implementing and operating one or more pseudo-synchronous registers with reduced power consumption, and reduced complexity for transferring data between clock domains. Various embodiments of the present invention replace conventional continuous clocking schemes with a strobe signal that is only generated when a data transfer operation with the one or more pseudo-synchronous registers is to take place. The strobe signal is generated so as to have a duration of one full cycle of the clock signal which defines the clock domain in which the at least one pseudo-synchronous register resides.

Abstract: Methods and apparatus for implementing and operating pulse width modulation based LED dimmer controllers are described. A synchronization protocol is used to allow control information for the dimmer operations to be transferred to the PWM dimmer control clock domain from an external clock domain, such that visual artifacts are prevented when the control information is updated. Control information may be transferred to the LED dimmer controller via an I2C serial bus, and the synchronization protocol waits for an I2C STOP condition before updating control information across clock domain boundaries. The leading and trailing edges of an asserted group dimmer control signal are generated such that the active portion of the group dimmer control signal overlaps the active portion of individual LED pulse width modulated control signals. In this way, the pulse width modulation of the individual LED control signals is not cut off, or reduced in width by the group dimmer signal.

Abstract: The present invention is a system and method that facilitates flexible restriction of output transmissions from chosen scan test cells and reduces adverse impacts on functional components from coincidental test vector values during scan test operations. The system and method of the present invention provides the capability of masking test vector values that coincidentally trigger certain undesirable events in functional components. In one embodiment, a system and method of the present invention masks test vector values shifted into scan test cells that are coupled to bus driver enabling signals. The system and method of the of the present invention also facilitates flexible selection of which scan test cell outputs are masked and permits a scan test cell to provide a scan test vector value to an associated functional component and prevent coincidental transmission of inappropriate test vector values.