Imprint-free coding for ferroelectric nonvolatile counters
AssigneeRamtron International Corporation
InventorsXiao Hong Du, Dennis C. Young
Life of this patent
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Abstract
An encoder utilizes a coding method for use with ferroelectric or other nonvolatile counters which are subject to imprint ensures that all of the bits in the code are frequently switched and not left in a fixed data state. The general coding equation for this method is such that: for an even integer n, it is represented by the conventional binary code of n/2; for an odd integer n, it is represented by the conventional binary code of the one's compliment of (n−1)/2. With this method, every bit switches to its compliment when counting from an even number to an odd number so that imprint is substantially reduced.
Claims18
An encoder for use in a nonvolatile counter comprising:
- a logic gate having a first input for receiving an up/down signal, a second input for receiving a most-significant bit signal, and an output;
- a plus-one block having an input for receiving an inverted input signal and an output;
- and
- a two-to-one multiplexer having a first input for receiving the inverted input signal, a second input coupled to the output of the plus-one block, a control input coupled to the output of the logic gate, and an output for providing an encoded signal.
A data encoding method for counting up from input number data n=dmdm-1dm-2 . . . d1d0 comprising:
- adding a logic one to inverted input number data to provide intermediate number data;
- multiplexing the inverted input number data and the intermediate number data to provide output number data;
- such that:
- if n is even, then the output number data comprises n+1= dm ddm-1 dm-2 . . . d1 d0;
- and
- if n is odd, then the output number data comprises n+1= dm dm-1 dm-2. . . d1 d0+1.
A data encoding method for counting down from input number data n=dmdm-1dm-2 . . . d1d0 comprising:
- adding a logic one to inverted in put number data to provide intermediate number data;
- multiplexing the inverted input number data and the intermediate number data to provide output number data;
- such that:
- if n is even, then the output number data comprises n−1= dm dm-2. . . d1 d030 1 ;
- and
- if n is odd, then the output number data comprises n−1= dm dm-2. . . d1 d0.
Dependencies are inferred from the claim text.