System and method for automatic deskew across a high speed, parallel interconnection

An automatic deskew system for use in high-speed, parallel interconnections for a digital system for correcting skew on each of said parallel interconnections, comprising:

• a plurality of deskew subsystems, each of said deskew subsystems coupled to an associated interconnection, said deskew subsystem capable of unfolding and correcting a signal on said associated interconnection having skew to align said signal on said associated interconnection with other bits received from other interconnections;
• and
• a deskew controller for automatically computing an amount of delay needed for each interconnection to align the signals on each interconnection, said deskew controller coupled to said plurality of deskew subsystems and including
• (a) a selector coupled to the outputs of each of said deskew subsystems and capable of selecting between or among the outputs of said deskew subsystems,
• (b) two pairs of all-zero and all-one detectors, one pair coupled to the output of said selector and the other pair coupled to the outputs of said deskew subsystems, said all-zero detector capable of indicating whether all the inputs thereto are zeroes, said all-one detector capable of indicating whether all the inputs thereto are ones,
• (c) a controller coupled to said selector and said pairs of all-zero and all one detectors, said controller capable of computing and sending a control value to said selector for selection between or among the outputs of said deskew subsystems, wherein said controller includes
• (i) a phase state register capable of receiving a signal to enable initiation and termination of phase one and phase two tuning for determining delay values,
• (ii) a phase one state register coupled to said phase state register and capable of receiving a phase one tuning start signal from said phase state register and to compute delay values,
• (iii) a phase one line selector coupled to said phase one state register and capable of selecting the outputs of one of several interconnections in said digital system and associating a delay value computed by said phase one state register therewith,
• (iv) a phase one line select register coupled to said phase one state register and said phase one line selector, said phase one line select register capable of computing control signals for said phase one line selector,
• (v) a phase two state register coupled to said phase state register and capable of receiving a phase two tuning start signal from said phase state register and to compute delay values,
• (vi) a phase two line selector coupled to said phase two state register and capable of selecting the outputs of one of several interconnections in said digital system and associating a delay value computed by said phase two state register therewith,
• (vii) a phase two line select register coupled to said phase two state register and said phase two line selector, said phase two line select register capable of computing control signals for said phase two line selector, and
• (viii) a select stage coupled to and capable of receiving input signals from said phase state register, said phase one line select register and said phase two line select register, and
• (d) a plurality of registers coupled to said controller and said deskew subsystems, said registers containing delay control values computed by said deskew controller for correcting skew on each interconnection.

A deskew controller for generating delay values for interconnections in a digital system having skew comprising:

• a selector configured to receive a plurality of input signals and capable of selecting between or among said input signals;
• two pairs of all-zero and all-one detectors, one pair coupled to the output of said selector and the other pair configured to receive as inputs said plurality of input signals of said selector, said all-zero detector capable of indicating whether all the inputs thereto are zeroes, said all-one detector capable of indicating whether all the inputs thereto are ones;
• a controller coupled to said selector and said pairs of all-zero and all-one detectors, said controller capable of computing and sending a control value to said selector for selection between or among the inputs of said selector, wherein said controller includes
• (a) a phase state register capable of receiving a signal to enable initiation and termination of phase one and phase two tuning for determining delay values,
• (b) a phase one state register coupled to said phase state register and capable of receiving a phase one tuning start signal from said phase state register and to compute delay values,
• (c) a phase one line selector coupled to said phase one state register and capable of selecting the outputs of one of several interconnections in said digital system and associating a delay value computed by said phase one state register therewith,
• (d) a phase one line select register coupled to said phase one state register and said phase one line selector, said phase one line select register capable of computing control signals for said phase one line selector,
• (e) a phase two state register coupled to said phase state register and capable of receiving a phase two tuning start signal from said phase state register and to compute delay values,
• (f) a phase two line selector coupled to said phase two state register and capable of selecting the outputs of one of several interconnections in said digital system and associating a delay value computed by said phase two state register therewith,
• (g) a phase two line select register coupled to said phase two state register and said phase two line selector, said phase two line select register capable of computing control signals for said phase two line selector, and
• (h) a select stage coupled to and capable of receiving input signals from said phase state register, said phase one line select register and said phase two line select register;
• and
• a plurality of registers coupled to said controller, said registers containing delay values computed by said deskew controller for correcting skew on each interconnection.