Sun Microsystems, Inc.

Oracle America, Inc.

Dong Joon Yoon

Drew George Doblar

Dawei Huang

Claude R Gauthier

Brian W Amick

Gajendra Prasad Singh

Zuxu Qin

Aparna Ramachandran

Tri K Tran

Waseem Ahmad

Osman Javed

Nirmal Chindhu Warke

Deqiang Song

Andrew Keith Joy

Muthukumar Vairavan

William Franklin Leven

Daniel J Beckman

Simon Dennis Forey

A system and method include a SerDes transmitter comprising a digital block operating in a digital voltage domain. The digital block can be configured to receive a first group of bits of data in parallel and store history bits from another group of data. The SerDes transmitter can further comprise an analog block operating in an analog voltage domain. The analog block can be configured to receive the first group of bits of data from the digital block, receive the history bits from the digital block, generate a plurality of combinations of bits with one or more bits from the first group of bits and zero or more bits from the history bits, align each combination of bits to a phase of a multi-phase clock; and input each combination into an output driver.

Power and area efficient SerDes transmitter

A feedback module is defined to receive as input a set of data sample signals and a set of reference sample signals. Each of the data and reference sample signals is generated by sampling a differential signal having been transmitted through a FIR filter. The feedback module is defined to operate a respective post cursor counter for each post cursor of the FIR filter and update the post cursor counters based on the received sets of data and reference sample signals. Also, the feedback module is defined to generate a tap weight adjustment signal for a given tap weight of the FIR filter when a magnitude of a post cursor counter corresponding to the given tap weight is greater than or equal to a threshold value. An adaptation module is defined to adapt a reference voltage used to generate the reference sample signals to a condition of the differential signal.

Real-time optimization of TX FIR filter for high-speed data communication

An analog baud rate clock and data recovery apparatus includes a first track and hold circuit that delays a received signal by one unit interval to create an odd signal; a second track and hold circuit that delays the received signal by one unit interval to create an even signal; a first comparator circuit; and a second comparator circuit. The first track and hold circuit outputs the odd signal to the first comparator circuit and the second comparator circuit. The second track and hold circuit outputs the even signal to the first comparator circuit and the second comparator circuit. The first comparator adds the odd signal to the even signal and outputs a first potential timing error. The second comparator subtracts the odd signal and the even signal and outputs a second potential timing error signal. A desired timing error signal is derived from the first and second potential timing error signals. The desired timing error signal is used to determine whether signal sampling is early or late.

Analog baud rate clock and data recovery

A data communications system and methods are disclosed. The system includes a transmitter for conveying a data signal filtered by a finite impulse response (FIR) filter to a receiver via a channel. The receiver equalizes the received data signal using a decision feedback equalizer (DFE) and the FIR. The receiver samples the data signal to determine an error signal and uses the error signal to adapt settings of a pre-cursor tap coefficient of the FIR, one or more post-cursor tap coefficients of the FIR, a phase of the recovered clock, and a coefficient of the DFE. To adapt the settings, the receiver determines the error signal based on an error sample taken from the data signal in a single clock cycle. To determine an error signal, the receiver samples the data signal at a phase estimated to correspond to a peak amplitude of a pulse response of the channel.

Integrated equalization and CDR adaptation engine with single error monitor circuit

A digital delay-locked loop has been discovered having a reduced area as compared to typical register-controlled delay-locked loops (RDLLs) used to control strobe delay lines that provide delay to strobe signals driving asynchronous FIFOs. This result is achieved by reducing ratio computation (i.e. gear logic) circuitry of the RDLL. A master delay line receives a control code to delay a reference clock by one clock period. A slave delay line receives the control code to delay a strobe signal by a predetermined fraction of the clock period. The master delay line may include individual sections responsive to the control code which effectively delay a signal by a portion of the clock period, the delay having a fixed relationship to a delay associated with individual sections of the slave delay line.

Generating different delay ratios for a strobe delay

A digital delay locked loop uses a delay array to delay an input signal by an amount indicated by a delay code. A phase of the resulting delayed signal is compared to a corresponding phase of the input signal, and dependent on the comparison, the delay code is updated to indicate whether the delay array needs to provide more delay or less delay. The digital delay locked loop also uses a detection circuit that monitors for a predetermined condition of the delay code. In response to detection of the predetermined condition, the delay code is automatically reset to a value different than a value of the delay code present at a previous reset or initial startup of the digital delay locked loop.

Digital delay locked loop with extended phase capture range

Growing community of inventors

San Jose, CA, United States of America

Dong Joon Yoon