Arm Limited

Yannick Marc Nevers

Nicolaas Klarinus Johannes Van Winkelhoff

Vincent Philippe Schuppe

Virgile Javerliac

Christophe Denis Lucien Frey

Bastien Jean Claude Aghetti

Mikael Brun

Stephane Zonza

Selma Laabidi

Laurent Christian Sibuet

A memory, a data processing system comprising a memory, a method of operating a memory and a memory compiler apparatus and method of memory compilation are provided, which relate to a memory comprising data storage circuitry to store data values at data locations. Addressing circuitry is provided to access the data value at a storage location in dependence on a received address and readout circuitry to provide an output value in dependence on the accessed data value. The memory further comprises scrambling circuitry to select at least one of: a mapping between the address and the storage location; and a mapping between the data value and the output value, in dependence on a received scrambling value. The mapping between the address and the storage location and/or the data value and the output value can thus be easily and rapidly changed.

Dynamic memory scrambling

A latching circuit has an input for receiving the data value, an output for outputting a value indicative of the data value, a clock signal input for receiving a clock signal; and a pass gate. A feedback loop has two switching circuits arranged in parallel between two inverting devices, a first of the two switching circuits is configured to be off and not conduct in response to a control signal having a predetermined control value and a second of the two switching circuits is configured to be on and conduct in response to the control signal having the predetermined control value. A control signal controlling the two switching circuits is linked such that the switching devices switch their conduction status and the access control device act together to update the data value within the feedback loop.

Low power latching circuits

A method of generating a ROM bit cell array layout including the steps of: inputting a predetermined memory architecture having a predetermined positioning of bit lines and virtual ground lines, the memory architecture including a plurality of columns of memory cells, each column of memory cells being located between associated bit lines and virtual ground lines. Adjacent memory cells in each column of memory cells share a common connection to either the associated bit line or the associated virtual ground line. The further steps of evaluating the width of active area of each of said columns of memory cells, in dependence on said predetermined positioning of bit lines and virtual ground lines; selecting a final width of active area in dependence on at least one performance characteristic associated with said final width of active area; and generating the layout according to said final width of active area.

Generating ROM bit cell arrays

A method of generating a ROM bit cell array layout is provided, the method comprising the steps of: inputting a predetermined memory architecture having a predetermined positioning of bit lines and virtual ground lines, said memory architecture comprising a plurality of columns of memory cells, each column of memory cells being located between its own associated bit line and its own associated virtual ground line, and adjacent memory cells in each column of memory cells sharing a common connection to either said associated bit line or said associated virtual ground line; evaluating a possible range of width of active area of each of said columns of memory cells, in dependence on said predetermined positioning of bit lines and virtual ground lines; selecting a final width of active area in dependence on at least one performance characteristic associated with said final width of active area; and generating said ROM bit cell array layout according to said final width of active area. Thus the system designer can reuse an existing memory architecture, yet still retain an advantageous degree of flexibility with regard to performance characteristic selection of the final ROM bit cell array.

A read only memory cell for storing a multiple bit value is disclosed. The read only memory cell comprises: at least three output lines, each of the at least three output lines representing a different multiple bit value; a switching device connected between a single one of the three output lines and a voltage source. The switching device provides an electrical connection between the voltage source and the single one of the three output lines in response to a switching signal, a voltage of the connected output line switching value in response to connection to the predetermined voltage and the multiple bit value represented by the output line is thereby selected. There is also an output device provided for outputting the selected multiple bit value.

Growing community of inventors

Grenoble, France

Yannick Marc Nevers