Abstract: Transceiver circuitry may include a storage element that receives data signals from an external element, an alignment detector circuit, and a register. The storage element has a write clock terminal that receives a channel clock signal and a read clock terminal that receives another channel clock signal. The alignment detector circuit is adapted to generate an asserted ready signal when a predefined pattern is detected in the received data signals. The register receives an output signal from the storage element and outputs the output signal based on the asserted ready signal that is generated by the alignment detector circuit. The register may be clocked by the same channel clock signal that is received at the read clock terminal of the storage element.

Abstract: Circuits and techniques for operating an integrated circuit are disclosed. A disclosed method includes receiving a data packet with a first operating frequency rate with first and second receiver circuits. The data packet may include a plurality of preamble bits. The first and second receiver circuits may operate at second and third operating frequency rates, respectively. A portion of the data packet received at the first receiver circuit is transmitted to a control circuit. The plurality of preamble bits within the portion of the data packet is identified with the control circuit. A clock circuit is then calibrated based on the plurality of preamble bits. The first and second receiver circuits may be clocked with first and second clock outputs from the clock circuit.

Abstract: Techniques for sampling input data streams with an integrated circuit (IC) are provided. The technique includes receiving a first input stream at a first operating rate. The first input stream is transmitted to a plurality of subsequent transceiver channels on the IC. The first input stream is then sampled at a second operating rate at each of the plurality of subsequent transceiver channels with each of the plurality of subsequent transceiver channels outputting a data stream at the second operating rate. The data stream from each of the plurality of subsequent transceiver channels is adjusted. A data stream from one of the plurality of subsequent transceiver channels is selected as an output of the IC.

Abstract: An integrated circuit (IC) is provided. The IC includes a transceiver, a boundary scan chain and a plurality of routable pathways. The transceiver includes an interconnection coupling circuit components. The transceiver receives data and transfers the received data through the interconnection. The received data is utilized to test the interconnection between the circuit components. The transceiver deserializes the data once the data completes its propagation through the interconnection. The boundary scan chain receives and shifts the deserialized data from the transceiver and transfers the shifted deserialized data out of the IC. The shifting is performed when asserted with an instruction of an Input Output (IO) standard. The plurality of routable pathways provides a pathway between the transceiver and the boundary scan chain so that the deserialized data may propagate.

Abstract: Integrated circuits with data communications circuitry are provided. The data communications circuitry on an integrated circuit may receive data that was transmitted from another integrated circuit at a data rate. The data communications circuitry may include oversampling circuitry that oversamples the data to produce an oversampled version of the data at an oversampled data rate. Downsampling circuitry in the data communications circuitry may be used to downsample the oversampled data. The downsampling circuitry may include cascaded groups of registers that store the oversampled data. The outputs of each of the groups of registers may be combined to form a combined parallel output. A downsampling control circuit may have a multiplexer that selects a subset of the signals from the combined parallel output in response to control signals from a transition detector. A middle bit detector may extract a bit value from the selected subset to use as the downsampled output.