Method and apparatus for performing butterfly differential signaling

An apparatus for performing differential signaling through parallel ports in a manner that reduces noise caused by coupling between neighboring ports, comprising:

• a set of parallel ports for transmitting differential signals from a sender to a receiver;
• wherein the set of parallel ports is organized in a two-dimensional grid;
• wherein each differential signal is transmitted through a first port and a second port that carry complementary positive and negative components of the differential signal;
• wherein the first and second ports of a differential pair are diagonally adjacent to each other in the two-dimensional grid;
• whereby because the first and second ports transition in opposite directions, coupling noise is cancelled on a neighboring port that is horizontally adjacent to the first port and vertically adjacent to the second port, and wherein a transition on the neighboring port couples equally to the first and second ports and is consequently rejected as common-mode noise by a corresponding differential receiver,
• wherein four differential pairs in the two-dimensional grid are arranged into a tiling pattern that can be replicated to cover the two-dimensional grid, wherein:
• a second component of a first pair is adjacent to the northeast of a first component of the first pair;
• a first component of a second pair is adjacent to the north of the first component of the first pair and is adjacent to the west of the second component of the first pair;
• a second component of the second pair is adjacent to the northwest of the first component of the second pair;
• a first component of a third pair is adjacent to the north of the first component of the second pair and is adjacent to the east of the second component of the second pair;
• and
• a second component of the third pair is adjacent to the northeast of the first component of the third pair.

An computer system that performs differential signaling through parallel ports in a manner that reduces noise caused by coupling between neighboring ports, comprising:

• a processor;
• a memory;
• a set of parallel ports within the processor and/or the memory for transmitting differential signals from a sender to a receiver;
• wherein the set of parallel ports is organized in a two-dimensional grid;
• wherein each differential signal is transmitted through a first port and a second port that carry complementary positive and negative components of the differential signal;
• wherein the first and second ports of a differential pair are diagonally adjacent to each other in the two-dimensional grid;
• whereby because the first and second ports transition in opposite directions, coupling noise is cancelled on a neighboring port that is horizontally adjacent to the first port and vertically adjacent to the second port, and wherein a transition on the neighboring port couples equally to the first and second ports and is consequently rejected as common-mode noise by a corresponding differential receiver,
• wherein four differential pairs in the two-dimensional grid are arranged into a tiling pattern that can be replicated to cover the two-dimensional grid, wherein:
• a second component of a first pair is adjacent to the northeast of a first component of the first pair;
• a first component of a second pair is adjacent to the north of the first component of the first pair and is adjacent to the west of the second component of the first pair;
• a second component of the second pair is adjacent to the northwest of the first component of the second pair;
• a first component of a third pair is adjacent to the north of the first component of the second pair and is adjacent to the east of the second component of the second pair;
• and
• a second component of the third pair is adjacent to the northeast of the first component of the third pair.