Patent ID: 7760836

Claim:
A skew detection apparatus detecting the amount of skew in at least one of a plurality of transmitting lanes, in relation to a reference lane, of a parallel data transmission system, comprising: (a) a plurality of transmitting lane pairs with one of a plurality of transceivers for each of said plurality of transmitting lane pairs, said plurality of transceivers comprising a transmitter and a receiver, wherein one of said plurality of transmitting lane pairs is a reference lane and one of said plurality of transceivers is a reference transceiver; (b) a internal loopback coupled from one or more outputs from said transmitter to one or more inputs of said receiver via a switch, wherein said switch selects data from a plurality of data, said plurality of data comprising regular data and internal loopback data, wherein said switch selects one of said plurality of data, whereby any other of said plurality of data can subsequently be selected by said switch to change from one of said plurality of data to any other of said plurality of data; (c) a connected communication element coupled to a receiving chip via a chip receive path; and (d) a logic circuit to implement at least one equation to detect a plurality of skew constants via a mode of empirical testing, said plurality of skew constants comprising internal skew constants and external skew constants, wherein said internal skew constants are located thin said transceivers and said external skew constants are located across said chip receive path, wherein said plurality of skew constants indicate skew in any of said plurality of transmitting lane pairs.