Abstract: A circuit includes first and second aligner circuits and a deskew circuit. The first aligner circuit is operable to align a first input serial data signal with a control signal to generate a first aligned serial data signal. The second aligner circuit is operable to align a second input serial data signal with the control signal to generate a second aligned serial data signal. The deskew circuit is operable to reduce skew between the first and the second aligned serial data signals to generate first and second output serial data signals.

Abstract: Serializer circuitry for high-speed serial data transmitter circuitry on a programmable logic device (“PLD”) or the like includes circuitry for converting parallel data having any of several data widths to serial data. The circuitry can also operate at any frequency in a wide range of frequencies, and can make use of reference clock signals having any of several relationships to the parallel data rate and/or the serial data rate. The circuitry is configurable/re-configurable in various respects, at least some of which configuration/re-configuration can be dynamically controlled (i.e., during user-mode operation of the PLD).

Abstract: An integrated circuit includes a local clock network that is operable to provide a first clock signal and an interface circuit that is coupled to receive the first clock signal from the local clock network. The interface circuit is operable to generate a second clock signal based on the first clock signal. A clock line is coupled to the interface circuit. The clock line has a fixed length. The second clock signal is provided to a multiplexer circuit through the clock line. The multiplexer circuit provides a third clock signal based on the second clock signal. Another clock network is coupled to receive the third clock signal from the multiplexer circuit.

Abstract: Disclosed are apparatus and methods for providing a serial interface with shared datapaths. The apparatus and methods share or re-use components from multiple lower-speed datapaths so as to efficiently provide a higher-speed datapath. In one embodiment, physical coding sublayer circuitry of the lower-speed datapaths is also used by the higher-speed datapath. In another embodiment, physical media access circuitry of the lower-speed data paths is also used by the higher-speed datapath. Other embodiments, aspects and features are also disclosed.

Abstract: Serializer circuitry for high-speed serial data transmitter circuitry on a programmable logic device (“PLD”) or the like includes circuitry for converting parallel data having any of several data widths to serial data. The circuitry can also operate at any frequency in a wide range of frequencies, and can make use of reference clock signals having any of several relationships to the parallel data rate and/or the serial data rate. The circuitry is configurable/re-configurable in various respects, at least some of which configuration/re-configuration can be dynamically controlled (i.e., during user-mode operation of the PLD).

Abstract: Phase locked loop circuitry operates digitally, to at least a large extent, to select from a plurality of phase-distributed candidate clock signals the signal that is closest in phase to transitions in another signal such as a clock data recovery (“CDR”) signal. The circuitry is constructed and operated to avoid glitches in the output clock signal that might otherwise result from changes in selection of the candidate clock signal. Frequency division of the candidate clock signals may be used to help the circuitry support serial communication at bit rates below frequencies that an analog portion of the phase locked loop circuitry can economically provide. Over-transmission or over-sampling may be used on the transmit side for similar reasons.

Abstract: Phase locked loop circuitry operates digitally, to at least a large extent, to select from a plurality of phase-distributed candidate clock signals the signal that is closest in phase to transitions in another signal such as a clock data recovery (“CDR”) signal. The circuitry is constructed and operated to avoid glitches in the output clock signal that might otherwise result from changes in selection of the candidate clock signal. Frequency division of the candidate clock signals may be used to help the circuitry support serial communication at bit rates below frequencies that an analog portion of the phase locked loop circuitry can economically provide. Over-transmission or over-sampling may be used on the transmit side for similar reasons.

Abstract: Phase locked loop circuitry operates digitally, to at least a large extent, to select from a plurality of phase-distributed candidate clock signals the signal that is closest in phase to transitions in another signal such as a clock data recovery (“CDR”) signal. The circuitry is constructed and operated to avoid glitches in the output clock signal that might otherwise result from changes in selection of the candidate clock signal. Frequency division of the candidate clock signals may be used to help the circuitry support serial communication at bit rates below frequencies that an analog portion of the phase locked loop circuitry can economically provide. Over-transmission or over-sampling may be used on the transmit side for similar reasons.

Abstract: Serializer circuitry for high-speed serial data transmitter circuitry on a programmable logic device (“PLD”) or the like includes circuitry for converting parallel data having any of several data widths to serial data. The circuitry can also operate at any frequency in a wide range of frequencies, and can make use of reference clock signals having any of several relationships to the parallel data rate and/or the serial data rate. The circuitry is configurable/re-configurable in various respects, at least some of which configuration/re-configuration can be dynamically controlled (i.e., during user-mode operation of the PLD).

Abstract: Phase locked loop circuitry operates digitally, to at least a large extent, to select from a plurality of phase-distributed candidate clock signals the signal that is closest in phase to transitions in another signal such as a clock data recovery (“CDR”) signal. The circuitry is constructed and operated to avoid glitches in the output clock signal that might otherwise result from changes in selection of the candidate clock signal. Frequency division of the candidate clock signals may be used to help the circuitry support serial communication at bit rates below frequencies that an analog portion of the phase locked loop circuitry can economically provide. Over-transmission or over-sampling may be used on the transmit side for similar reasons.

Abstract: Serializer circuitry for high-speed serial data transmitter circuitry on a programmable logic device (“PLD”) or the like includes circuitry for converting parallel data having any of several data widths to serial data. The circuitry can also operate at any frequency in a wide range of frequencies, and can make use of reference clock signals having any of several relationships to the parallel data rate and/or the serial data rate. The circuitry is configurable/re-configurable in various respects, at least some of which configuration/re-configuration can be dynamically controlled (i.e., during user-mode operation of the PLD).

Abstract: A serial interface for a programmable logic device supports a wide range of data rates by providing a first number of channels supporting a first range of data rates and a second number of channels supporting a second range of data rates. The first range of data rates is preferably lower than the second range of data rates and preferably the first number of channels is higher than the second number of channels which preferably is 1. For backward compatibility with existing devices, the first number of channels in each interface preferably is four. Each channel preferably includes a physical medium attachment module and a physical coding sublayer module. Each of the higher-speed channels in the second number of channels preferably also includes a clock management unit, while the lower-speed channels in the first number of channels preferably share one or more clock management units.

Abstract: Deserializer circuitry for high-speed serial data receiver circuitry on a programmable logic device (“PLD”) or the like includes circuitry for converting serial data to parallel data having any of several data widths. The circuitry can also operate at any frequency in a wide range of frequencies. The circuitry is configurable/re-configurable in various respects, at least some of which configuration/re-configuration can be dynamically controlled (i.e., during user-mode operation of the PLD).

Abstract: An integrated circuit like a programmable logic device (“PLD”) includes multiple channels of data communication circuitry. Circuitry is provided for selectively sharing signals (e.g., control-type signals) among these channels in groupings of various size so that the device can better support communication protocols that require various numbers of channels (e.g., one channel operating relatively independently, four channels working together, eight channels working together, etc.). The signals shared may include a clock signal, a FIFO write enable signal, a FIFO read enable signal, or the like. The circuit arrangements are preferably modular (i.e., the same or substantially the same from one channel to the next and/or from one group of channels to the next) to facilitate such things as circuit design and verification.

Abstract: In a programmable logic device, some or all of the parallel interconnect resources are replaced by serial interconnect resources within the device. Some or all of the functional blocks on the device are supplemented with serial interfaces. Although this makes the functional blocks more complex, it allows a significant reduction in the area consumed by interconnect resources. This translates into a significant reduction in device power consumption. The serial interfaces may operate synchronously from a global device clock (such as a PLL). In some cases, serial interfaces that are provided in the input/output blocks for external signalling can be omitted because the serial interfaces in the functional blocks can take over the external serial interface function as well, although in those cases the serial interfaces in the functional blocks would have to be more complex because they would have to be able to operate asynchronously with external devices.

Abstract: A programmable logic device (“PLD”) includes communication interface circuitry that can support any of a wide range of communication protocols, including Packet Over Sonet (“POS-5”) and 8-bit/10-bit (“8B10B”) protocols. The interface circuitry includes various functional blocks that are at least partly hard-wired to perform particular types of functions, but that in at least many cases are also partly programmable to allow the basic functions to be adapted for various protocols. Routing of signals to, from, between, and/or around the various functional blocks is also preferably at least partly programmable to facilitate combining the functional blocks in various ways to support various protocols.

Abstract: A serial interface for a programmable logic device can be operated according to various communications protocols and includes both a receiver portion and a transmitter portion. The receiver portion includes at least a word or byte alignment stage, a de-skew stage, a rate compensation or matching stage, a padded protocol decoder stage (e.g., 8B/10B decoder circuitry or 64B/66B decoder circuitry), a byte deserializer stage, a byte reorder stage, and a phase compensation stage. The transmitter portion includes at least a phase compensation stage, a byte deserializer stage, and a padded protocol encoder stage (e.g., an 8B/10B encoder circuitry or 64B/66B encoder circuitry). Each stage may have multiple occurrences of relevant circuitry. Selection circuitry, such as multiplexers, selects the appropriate stages, and circuitry within each stage, for the protocol being used.

Abstract: Transmitter and receiver circuitry for 64b/66b encoding or other similar padded data signalling. The required transmitter clock circuitry is simplified by using one clock signal source as a basis for at least partly processing the data both before and after padding. Appropriate frequency multiplication and division factors are employed to make this possible. Similar techniques are used in receiver circuitry.

Abstract: Eight-bit ten-bit (8B10B) coding is provided in a hard intellectual property (IP) block with the capability of supporting a greater range of data rates (e.g., data rates less than, equal to, and greater than 3.125 Gbps). Each channel of high speed serial interface circuitry includes receiver circuitry having two 8B10B decoders and transmitter circuitry having two 8B10B encoders. The receiver and transmitter circuitry can be configured to operate in one of three modes of operation: cascade mode, dual channel mode, and single channel mode.

Abstract: A programmable logic device (“PLD”) is augmented with programmable clock data recover (“CDR”) circuitry to allow the PLD to communicate via any of a large number of CDR signaling protocols. The CDR circuitry may be integrated with the PLD, or it may be wholly or partly on a separate integrated circuit. The circuitry may be capable of CDR input, CDR output, or both. The CDR capability may be provided in combination with other non-CDR signaling capability such as non-CDR low voltage differential signaling (“LVDS”). THE CDR circuitry is provided with a programmable serializer and/or deserializer that can support higher data clock rates than the highest clock rate associated with the reference clock signal or clock signal from a phase locked loop circuit.