Lsi Corporation

Lsi Logic Corporation

Christopher D Paulson

Timothy D Thompson

Steven Schauer

Kevin T Campbell

Cheng-Gang Kong

Terence J Magee

David O Sluiter

David A Thomas

Mark Buchanan

Kevin Campbell

A non-linear common coarse delay system and method for delaying a data strobe in order to preserve fine delay accuracy and compensate PVT (Process, Voltage, and Temperature) variation effects. A common coarse delay and a fine delay can be initialized to a quarter-cycle delay for shifting a read output DQS (Data Queue Strobe) associated with a memory device in order to sample a read output DQ (Data Queue) within a physical layer. The fine delay can be programmed from minimum to maximum delay with fixed linear increments at each delay step in order to determine the resolution and accuracy of the delay. An optimum delay size of both the coarse and the fine delay can be determined based on an application slowest frequency of operation. A spare coarse delay and a functional coarse delay can be trained in association with a spare fine delay and the functional fine delay can be updated in order to monitor the process, voltage, and temperature variation effects.

Non-linear common coarse delay system and method for delaying data strobe

Disclosed is a method for reducing latency between two clock domains in a digital electronic device. The time between a write to a queue position and a corresponding read of the queue position is reduced by up to one clock cycle by including a delay in the time before first writing data to a First In First Out (FIFO) queue used to buffer and synchronize data between two clock domains. The two clock domains have the same frequency, but may be out of phase. Reducing the latency between the write and the corresponding read reduces the required size of the FIFO queue and also results in more efficient system operation.

Method for reducing latency

A method for discarding perpetually-rejected packets in a fabric-based interconnect having a reliable physical layer is disclosed. A transmitting component keeps a count of the number of negative acknowledgements (NAKs) it receives from the receiving component for packets the transmitting component sends. If the transmitting component receives a number of consecutive NAKs for the same packet that exceeds some pre-determined threshold, the packet is not resent, but is, instead, treated as having been acknowledged, and subsequent packets are allowed to be transmitted. Higher-level processes are then notified of the problem so as to allow the error to be dealt with at a higher level, but without obstructing the flow of packets on the physical layer.

Method for discarding corrupted data packets in a reliable transport fabric

Disclosed is an adaptive method for training a source synchronous parallel receiver. The adaptive method for training, or aligning, parallel data channels permits a parallel communication receiver to adaptively adjust the timing of data channels to align the data channels with a frame channel and achieve a source synchronous signal for the parallel data channels. Further, portions of the frame channel training pattern may be used because possible time shift accuracy error is accounted for between the communication channels and a determination is made as to which portion of the frame pattern is currently being received. The data channels are then aligned appropriately.

Adaptive method for training a source synchronous parallel receiver

A packetized data bus interface may be placed in a mode where data packets may be transmitted that are much larger than the standard packet size. The mode may allow the interface device and any other devices, networks, or transmission lines attached to the interface device to be more thoroughly exercised than previously able. The mode may be used for characterizing various aspects of the data interface.

Large transmissions on packetized data bus

An elasticity buffer has a reset input that, when activated, causes the elasticity buffer to temporarily cease operation. When the reset input bit is released, the elasticity buffer may resume operation. During periods when a device on a serial bus may be halted for power saving mode, for example, the serial communication may be reestablished and then the elasticity buffer may be released to continue operation.

Elasticity buffer restarting

An apparatus comprising a first circuit and a second circuit. The first circuit may be configured to store input data in response to a write pointer and present output data in response to a read pointer. The second circuit may be configured to generate a control signal in response to the write pointer, the read pointer and a type of an information packet containing the input data.

Active FIFO threshold adjustment

Disclosed is a method for minimizing the buffer size of an elasticity FIFO queue when synchronizing data between two clock domains. Data communication is typically sent by a transmitter device to a receiver device. The transmitted data signal includes an embedded clock signal and null data characters, as specified by the data communication signal protocol. A null character indicates an empty data frame and is included as part of most standard communication protocols. An embodiment skips one or more null characters from the elasticity FIFO queue during a single clock cycle when it is detected that the write pointer is catching up to the read pointer. By skipping multiple null characters during a single write cycle, the read pointer is moved ahead by one or more queue locations and the write pointer is insured to not catch up to the read pointer for a wider variation in frequencies between a transmitter and receiver than is normally possible. Typically, the elasticity FIFO queue size must be increased in order to support a larger frequency variation. By reducing the need to increase the elasticity FIFO queue size, the gate count and area needed for the elasticity FIFO queue on the silicon chip of the receiver is reduced, thus, reducing the cost contribution of the elasticity FIFO queue to the receiver device. Skipping null characters also reduces the latency time between a write and the associated read of a non-null data character.

Adaptive elasticity FIFO

A logical gate and a comparator are used to detect page boundaries in a data stream. A current address and a predetermined page size, that is an integer power of 2, are compared using a Boolean logic gate such as AND or XOR to detect a page boundary in a data stream. The output from the Boolean logic gate is compared to a predetermined value to cause a signal to be generated, indicating the end of the page.

Page boundary detector

An apparatus comprising one or more user programmable registers and a circuit configured to compare a predetermined portion of one or more information packets with contents of said one or more user programmable registers.

Method for receiving user defined frame information structure (FIS) types in a serial-ATA (SATA) system

An apparatus generally comprising a plurality of writeable registers, a control circuit, and a transmitter circuit. The writeable registers may be configured to store (i) a first burst value and (ii) a first gap value. The control circuit may be configured to generate an idle signal (i) in a transmit state for a first duration determined by the first burst value and (ii) in an idle state for a second duration determined by the first gap value in response to a first command signal. The transmitter circuit may be configured to (i) enable transmitting while the idle signal is in the transmit state and (ii) disable transmitting while the idle signal is in the idle state.

Programmable transmission and reception of out of band signals for serial ATA

A circuit generally comprising a first circuit and a second circuit. The first circuit may be configured to (i) detect a state of an input signal and (ii) present a plurality of intermediate signals each representative of the state of the input signal during a plurality of clock cycles. The second circuit may be configured to present a filtered signal in response to a selected number of the intermediate signals having a predetermined state.

Programmable digital filter implementation for loss-of-signal detection for serial communications applications

A system generally having a first circuit, a second circuit, and a pair of non-crossing conductive paths. The first circuit may be configured to convert between (i) a serial signal on a first differential interface and (ii) a parallel signal. The pair of non-crossing conductive paths may connect the first differential interface with a second differential interface. The second circuit may be configured to invert the parallel signal in response to a control signal in an inverting state.

Programmable polarity for high speed differential interfaces

A method and apparatus is provided for ensuring the integrity of data being transferred between two clock domains. Data is transferred on every clock signal from a faster clock domain to a slower clock domain. Data is collected by the data capture unit in two or more banks of registers for transfer to the second clock domain. The data collected has a first data size and is stacked with additional data of the first data size to generate data having a second data size. When two banks of registers are used, one bank of registers is being filled while the other bank of registers is passing data to the second clock domain. These two banks of registers provide two data paths to the synchronization logic for the second clock domain. This is especially advantageous when the limit of available bandwidth has been reached by one of the clock domains.

Method and apparatus for transferring data between a slower clock domain and a faster clock domain in which one of the clock domains is bandwidth limited

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Fort Collins, CO, United States of America

Christopher D Paulson