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: A serial interface for a programmable logic device includes receiver and transmitter portions, and an automatic speed negotiation module to adjust the data rates of both portions. The speed adjustment may be accomplished by adjusting the widths of the data paths in both portions. The speed adjustment occurs on receipt of a control signal generated elsewhere on the programmable logic device, or generated by the module. One reason for generating the control signal is the detection of data errors in the received data, or the detection of a delimiter pattern in the received data signifying that a remote device is about to change its data rate. Similarly, before changing its data rate, the module may insert a delimiter in the data in the transmitter portion. After receipt or transmission of a delimiter pattern, the module may wait for a predetermined delay period to elapse before changing the data rate.

Abstract: Systems and methods are provided using dynamically adjustable differential output drivers. Integrated circuits such as programmable logic devices may be provided with adjustable differential output drivers for transmitting high-speed data to other integrated circuits. The peak-to-peak output voltage and common-mode voltage of the output drivers may be adjusted. Dynamic control circuitry may be used to control the settings of current sources, programmable resistors, and voltage source circuitry in the adjustable differential output driver automatically in real time. The adjustable components in the differential output driver may be adjusted by the dynamic control circuitry based on feedback information received from the integrated circuit to which the data is transmitted.

Abstract: High-speed serial data transceiver circuitry on a programmable logic device (“PLD”) includes some channels that are able to operate at data rates up to a first, relatively low maximum data rate, and other channels that are able to operate at data rates up to a second, relatively high maximum data rate. The relatively low-speed channels are served by relatively low-speed phase locked loop (“PLL”) circuitry, and have other circuit components that are typically needed for handling data that is transmitted at relatively low data rates. The relatively high-speed channels are served by relatively high-speed PLLs, and have other circuit components that are typically needed for handling data that is transmitted at relatively high data rates.

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 integrated circuit device (“PLD”) includes high-speed serial interface (“HSSI”) circuitry that is at least partly hard-wired to perform at least some functional aspects of the HSSI operations. Cyclic redundancy check (CRC) generation and/or checking circuitry is now included in this HSSI circuitry, and again, this CRC circuitry is at least partly hard-wired to perform at least some functional aspects of its operations(s).

Abstract: High-speed serial data transceiver circuitry on a programmable logic device (“PLD”) includes some channels that are able to operate at data rates up to a first, relatively low maximum data rate, and other channels that are able to operate at data rates up to a second, relatively high maximum data rate. The relatively low-speed channels are served by relatively low-speed phase locked loop (“PLL”) circuitry, and have other circuit components that are typically needed for handling data that is transmitted at relatively low data rates. The relatively high-speed channels are served by relatively high-speed PLLs, and have other circuit components that are typically needed for handling data that is transmitted at relatively high data rates.

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: A programmable logic device (PLD) having one or more programmable logic regions and one or more conventional input/output regions additionally has one or more peripheral areas including specialized circuitry. The peripheral specialized regions, which are not connected to the remainder of the programmable logic device (and may be made on separate dies from the remainder of the programmable logic device mounted on a common substrate), and one or both of the programmable logic regions and the conventional I/O regions, have contacts for metallization traces or other interconnections to connect the peripheral specialized regions to the remainder of the programmable logic device. The same PLD can be sold with or without the specialized circuitry capability by providing or not providing the interconnections. The peripheral specialized regions may include high-speed I/O (basic, up to about 3 Gbps, and enhanced, up to about 10-12 Gbps), as well as other types of specialized 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: Systems and methods are provided using dynamically adjustable differential output drivers. Integrated circuits such as programmable logic devices may be provided with adjustable differential output drivers for transmitting high-speed data to other integrated circuits. The peak-to-peak output voltage and common-mode voltage of the output drivers may be adjusted. Dynamic control circuitry may be used to control the settings of current sources, programmable resistors, and voltage source circuitry in the adjustable differential output driver automatically in real time. The adjustable components in the differential output driver may be adjusted by the dynamic control circuitry based on feedback information received from the integrated circuit to which the data is transmitted.

Abstract: A programmable bit error rate monitor includes an error counter, a monitoring period counter with a programmable upper bound to set the monitoring period, and an error flag generator that compares the actual error count to a programmable threshold. The error flag generator may generate flags at different sensitivity levels, and the user may programmably select one of those flags. The three flags can be generated by independent comparators, or they can be extrapolated from the base error flag—e.g., by comparing only certain bits of the error count to corresponding bits of the threshold.

Abstract: A programmable logic device (“PLD”) includes high-speed serial interface (“HSSI”) circuitry. The HSSI circuitry includes clock signal circuitry that allows various components of the HSSI circuitry to be clocked in different ways to facilitate use of the HSSI circuitry to support a number of different communication protocols. Some of the HSSI clock signals may be routed through the clock distribution network of the associated PLD logic circuitry. The HSSI circuitry may include phase compensation buffer circuitry to compensate for possible phase differences across the interface between the HSSI circuitry and the associated PLD logic circuitry.

Abstract: Clock rate matching circuitry is provided to buffer data between two clock domains that may have slightly different frequencies. To facilitate supporting a wide range of different communication protocols, the clock rate matching circuitry includes dedicated control circuitry and is also associated with other circuitry that is capable of acting as control circuitry that can be used as an alternative to at least part of the dedicated control circuitry. For example, the dedicated control circuitry may be set up to support one or several industry-standard protocols. The other circuitry (which may be, for example, programmable logic circuitry) is available to support any of a wide range of other protocols, whether industry-standard or custom.

Abstract: A serial interface for a programmable logic device substantially eliminates skew across multiple channels both in the receiver and in the transmitter. Even when the channels are independent (e.g., are in different quads), skew is substantially eliminated by monitoring to determine when all channels have reached their active states (i.e., in the case of receiver channels when all channels have achieved byte alignment and have received an alignment character, and in the case of transmitter channels when all transmit PLLs have locked), and only then allowing data to flow between the serial and parallel domains.

Abstract: An I/O interface for configuring hard IP embedded in a FPGA includes a register load signal, a CSR initialization signal, and a register data signal. After programming the DPRIO registers, the register data controls the operation of the hard IP block. The interface supports both CSR load mode and the MDIO interface. The user-friendly I/O interface eliminates all requirements on the end-user and is virtually transparent to the end-user.

Abstract: An integrated circuit like a programmable logic device (“PLD”) includes a communication channel employing 8B/10B coding. Disparity information determined by 8B/10B decoder circuitry in the communication channel is supplied to other circuitry of the PLD so that any requirement for disparity to have a particular value in conjunction with certain received codes can be checked. On the transmitter side, circuitry is provided for selectively forcing the 8B/10B encoder to use a commanded disparity (which can be either positive or negative) under particular circumstances.

Abstract: A data converter, or “gearbox,” for a padded protocol interface uses a reduced number of components by processing a narrower intermediate data stream, while at the same time multiplying the clock speed of its intermediate input and output so that it processes more data per clock cycle. The data streams can be narrowed to any integer factor of the original width (other than the original width).

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.