Method and apparatus for adaptive bus coding for low power deep sub-micron designs

An encoding method for a plurality of closely spaced electrical signal paths on a substrate, wherein a predetermined set of synchronous electrical impulses traverse the electrical signal paths, the encoding method comprising:

• determining a signal transition history for each electrical signal path for the predetermined set of synchronous electrical impulses;
• dividing the electrical signal paths into a number of windows such that W=P/Ws, wherein each window comprises a number of adjacent electrical signal paths, and W represents the number of window, P represents the number of electrical signal paths, and Ws represents the number of electrical signal paths in a window;
• arranging the windows such that the two windows having electrical signal paths with the largest amount of signal transition history are separated by the remaining windows;
• and
• analyzing the signal transitions within each window, and if a majority of the windows contain a large amount of transition activity, inverting the synchronous electrical impulses.

An encoding method for an address bus on a substrate, wherein a given set of synchronous address bit signals traverse the address bus, the encoding method comprising:

• determining a signal transition history for each address bit on the address bus;
• dividing the address bus into a number of windows such that W=P/Ws, wherein W represents the number of windows, P represents the number of bits in the address bus, and Ws represents the number of address bus bits in a window;
• arranging the windows such that the two windows having address bus bits with the largest amount of signal transition history are separated by the remaining windows;
• and
• analyzing the address bus signal transitions within each window, and if a majority of the windows contain a large amount of transition activity, inverting the address bit signals traversing the address bus.

An encoding method for an address bus on a substrate, wherein a given set of synchronous address bit signals traverse the address bus, the encoding method comprising:

• determining a signal transition history for each address bit on the address bus;
• dividing the address bus into a number of windows such that W=P/Ws, wherein W represents the number of windows, P represents the number of bits in the address bus, and Ws represents the number of address bus bits in a window;
• arranging the windows such that windows having address bits with a large amount of signal transition history are separated by windows having address bits with a low amount of signal transition history.
• analyzing the address bus signal transitions within each window, and if a majority of the windows contain a large amount of transition activity, inverting the address bit signals traversing the address bus.