Abstract:
An integrated circuit capable of monitoring analog voltages inside an analog block is presented. The integrated circuit has an analog test multiplexer (mux) whose inputs are connected to analog voltages of interest inside an analog block. The analog test multiplexer directs a selected analog voltage from an analog block to the output of the analog test mux. The integrated circuit further includes an analog monitor state machine which provides the selection bits to the analog test multiplexer, enabling random access to the analog voltages inside the analog block. The integrated circuit also includes an analog to digital converter for converting the selected analog voltage from the analog test multiplexer into a digital representation.
Abstract:
Systems that provide integrated circuit device circuitry having an integrated optical-electronic interface for high-speed off-device communications are provided. An optical-electronic interface may be incorporated into an integrated circuit device, freeing up some or all of the electrical I/O pins of the integrated circuit device. Transceiver I/O channels may be provided on an integrated circuit device that can be switched between electrical and optical transceiver I/O channels.
Abstract:
An integrated circuit (e.g., a programmable integrated circuit such as a programmable microcontroller, a programmable logic device, etc.) includes programmable circuitry and 10 Gigabit Ethernet (10 GbE) transceiver circuitry. The programmable circuitry and the transceiver circuitry may be configured to implement the physical (PHY) layer of the 10 GbE networking specification. This integrated circuit may then be coupled to an optical transceiver module in order to transmit and receive 10 GbE optical signals. The transceiver circuitry and interface circuitry that connects the transceiver circuitry with the programmable circuitry may be hard-wired or partially hard-wired.
Abstract:
A buffer circuit includes a current source circuit, first and second switch circuits that are coupled to the current source circuit, a first resistor coupled to the first switch circuit, a second resistor coupled to the second switch circuit, and a third switch circuit coupled to the first and the second resistors. The third switch circuit couples the first and the second resistors to a node at a first voltage when the buffer circuit is configured to function in a current mode logic buffer mode. The third switch circuit couples the first and the second resistors to a node at a second voltage when the buffer circuit is configured to function in an H-bridge buffer mode.
Abstract:
Methods and apparatus are provided for generating a clock signal with relatively high bandwidth and relatively low phase noise. A circuit of the invention can include a pair of transistors serially coupled between a signal of relatively high voltage and a source of relatively low voltage, where a voltage of the signal of relatively high voltage can vary according to a voltage of a variable control signal. A gate of one of the pair of transistors can be coupled to an input clock signal, and an output node between the pair of transistors can be coupled to an output clock signal. The circuit can also include a third transistor, whose drain and source are coupled to the output clock signal, and whose gate can be coupled to a gear input signal. This circuit can advantageously operate under at least two different gears, each with different bandwidth and phase noise characteristics.
Abstract:
Circuitry for receiving a serial data signal (e.g., a high-speed serial data signal) includes adjustable equalizer circuitry for producing an equalized version of the serial data signal. The equalizer circuitry may include controllably variable DC gain and controllably variable AC gain. The circuitry may further include eye height and eye width monitor circuitry for respectively producing first and second output signals indicative of the height and width of the eye of the equalized version. The first output signal may be used in control of the DC gain of the equalizer circuitry, and the second output signal may be used in control of the AC gain of the equalizer circuitry.
Abstract:
A link simulation tool for simulating high-speed communications link systems is provided. Communications links may include link subsystems such as transmit (TX) circuitry, receive (TX) circuitry, oscillator circuits that provide reference clock signals to the TX and RX circuitry, and channels that link the TX and RX circuitry. The link simulation tool may model each of the subsystems using behavioral models. The behavioral models may include characteristic functions such as transfer functions, probability density functions, and eye characteristics. The link simulation tool may have a link analysis engine that is capable of performing two-dimensional (two-variable) convolution operations and in applying dual-domain (frequency-time) transformations on the characteristic functions provided by the behavioral models to simulate the performance of the link system. The link simulation tool may have an input screen that allows a user to specify desired link parameters and a data display screen that display simulated results.
Abstract:
A loss-of-signal detector includes digital and analog monitoring of incoming data. The incoming signal is compared digitally to at least one predetermined pattern that may indicate a loss of signal, and also is monitored by an analog detector that detects transitions in the data. If the digital comparison fails to match any of the at least one predetermined pattern, or if transitions are detected by the analog monitoring, even if the digital comparison produces a pattern match, then loss of signal is not indicated.
Abstract:
An integrated circuit (“IC”) may include clock and data recovery (“CDR”) circuitry for recovering data information from an input serial data signal. The CDR circuitry may include a reference clock loop and a data loop. A retimed (recovered) data signal output by the CDR circuitry is monitored by other control circuitry on the IC for a communication change request contained in that signal. Responsive to such a request, the control circuitry can change an operating parameter of the CDR circuitry (e.g., a frequency division factor used in either of the above-mentioned loops). This can help the IC support communication protocols that employ auto-speed negotiation.
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.