Skew-correcting apparatus using dual loopback
AssigneeAvalon Microelectronics, Inc.
InventorsWally Haas, Mutema John Pittman, Chuck Rumbolt
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Abstract
An apparatus for determining the amount of skew injected into a high-speed data communications system, including a plurality of lanes having a data bus per lane, relative to a reference lane, for system skew compensation. By knowing the relative amount of skew that each lane requires for alignment, an appropriate amount of skew is then injected on each lane to provide alignment and thus compliancy with the SFI-5 and SxI-5 standards, in terms of data skew specifications. The relative skew amounts for each transmitting lane are determined using dual loopback methods.
Claims14
A skew detection apparatus for 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) one of a plurality of transceivers coupled to one of said plurality of transmitting lane pairs, one of 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 dual loopback coupled from one or more outputs from said transmitter to one or more inputs of said receiver via a multiplexer, wherein said multiplexer selects data from a plurality of data, said plurality of data comprising regular data and a plurality of loopback data, wherein said multiplexer selects one of said plurality of data, whereby any other of said plurality of data can subsequently be selected by said multiplexer to change from one of said plurality of data to any other of said plurality of data;
- and
- (c) a logic circuit to implement an equation to detect an amount of skew in at least one of said plurality of transmitting lane pairs through said plurality of loopback data, whereby said amount of skew indicates offsetting skew to be injected into any of said plurality of transmitting lane pairs, at the transmit side of a circuit, to re-align said plurality of transmitting lane pairs and achieve transmission lane alignment.
A skew correction apparatus for detecting and correcting 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) one of a plurality of transceivers coupled to one of said plurality of transmitting lane pairs, one of 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 buffer to delay said plurality of transmitting lane pairs by a Unit Interval of Time (UI);
- and
- (c) a logic circuit to implement an equation to detect an amount of skew in at least one of said plurality of transmitting lane pairs through a plurality of loopback data, whereby said amount of skew indicates to said buffer the offsetting skew to be injected into any of said plurality of transmitting lane pairs, at the transmit side of a circuit, to re-align said plurality of transmitting lane pairs and achieve transmission lane alignment.
Dependencies are inferred from the claim text.