Broadcom Corporation

Conexant Systems, Inc.

Daniel Schoch

Mohammad Nejad

Guangming Yin

Sridevi R Joshi

Ichiro Fujimori

Wim F Cops

Naser Adas

A bit stream multiplexer includes an input ordering block, a plurality of multiplexers, an output ordering block, and a Pseudo Random Bit Stream (PRBS) function. The input ordering block is operates to receive a first plurality of transmit bit streams at a first bit rate, order the first plurality of transmit bit streams based upon a first order select signal, and produce a first plurality of ordered transmit bit streams at the first bit rate. The input ordering block may also deskew the first plurality of transmit bit streams. The plurality of multiplexers operate to receive the first plurality of ordered transmit bit streams at the first bit rate and produce an interface plurality of transmit bit streams at an interface bit rate. The output ordering block operates to order the interface plurality of transmit bit streams based upon an interface order select signal. The PRBS function produces a PRBS that is coupled to at least one of the interface plurality of transmit bit streams. A bit stream demultiplexer is similarly constructed.

Built-in-self test for high-speed serial bit stream multiplexing and demultiplexing chip set

A bit stream multiplexer and a bit stream demultiplexer of the present invention couples a communication Application Specific Integrate Circuit (ASIC) to a high-speed bit stream media. The bit stream multiplexer includes a first transmit data multiplexing integrated circuit having an input that receives a first plurality of bit streams at a first bit rate from the communication ASIC and an output that produces a second plurality of bit streams at a second bit rate, the second plurality having fewer bit streams than said first plurality. It further includes a second transmit data multiplexing integrated circuit having an input that receives the second plurality of bit streams at the second bit rate and an output that produces a single bit stream at a line bit rate, the single bit stream having a predetermined bit order. The bit stream demultiplexer includes similar demultiplexing integrated circuits. These circuits include an interface that may be ordered, have signal line polarities altered, or bit asserted states altered depending upon the particular implementation.

Signal line selection and polarity change of natural bit ordering in high-speed serial bit stream multiplexing and demultiplexing integrated circuits

A low-speed delay locked loop (DLL) facilitates a deskewed interface between a high-speed RX data demultiplexer circuit directly to an Application Specific Integrated Circuit (ASIC) with which it is integrated by locking a 156 MHz ASIC clock to a 156 MHz reference derived from a high speed 2.5 GHz clock. The DLL employs a digital interpolator to generate 32 phases of the 156 MHz clock. The digital interpolator supplies the phases using a double clocked shift register with recirculating feedback. The shift register is double clocked using the 2.5 GHz clock. The register outputs are tapped and fed to a 32:1 multiplexer having a phase select input that is controlled by the phase difference signal generated by the DLL. The phase difference control signal is converted to a digital representation of its magnitude by which the requisite number of phase shift increments may be selected. The phase chosen is that which eliminates any difference in the phases of the 156 MHz clock that clocks the data transmitted to the ASIC domain and the clock that is used in the ASIC domain to latch the data. Thus, the interpolator takes advantage of the availability of the high-speed clock to generate a sufficient number of phases for a low speed DLL.

Low-speed DLL employing a digital phase interpolator based upon a high-speed clock

A low-speed DLL facilitates a deskewed interface between a high-speed RX data demultiplexer circuit directly to an Application Specific Integrated Circuit (ASIC) with which it is integrated by locking a 156 MHz ASIC clock to a 156 MHz reference derived from a high speed 2.5 GHz clock. The DLL employs a digital interpolator to generate 32 phases of the 156 MHz clock. The digital interpolator supplies the phases using a double clocked shift register with recirculating feedback. The shift register is double clocked using the 2.5 GHz clock. The register outputs are tapped and fed to a 32:1 multiplexer having a phase select input that is controlled by the phase difference signal generated by the DLL. The phase difference control signal is converted to a digital representation of its magnitude by which the requisite number of phase shift increments may be selected. The phase chosen is that which eliminates any difference in the phases of the 156 MHz clock that clocks the data transmitted to the ASIC domain and the clock that is used in the ASIC domain to latch the data. Thus, the interpolator takes advantage of the availability of the high-speed clock to generate a sufficient number of phases for a low speed DLL.

An integrated circuit includes a core circuit and a buffer circuit. The buffer circuit includes a plurality of input buffers and a plurality of output buffers that service a plurality of voltage domains on a single set of input/output lines. These voltage domains are controllable to service multiple voltage levels, consistent with various interface standards. In one construction, the core circuit operates at 1.2 volts and the buffer circuit supports both a 1.2 volts interface standard and a 3.3 volts interface standard.

Switchable power domains for 1.2v and 3.3v pad voltages

Multiple ICs communicate with a controller through a shared bus. The ICs are also joined to an output of the controller in a daisy chain configuration. Each IC includes an input for receiving a signal on a link of the daisy chain and an output for providing a signal on a link of the daisy chain. The daisy chain links are used for address initialization. Thus only one controller pin and two IC pins are required for address initialization. The daisy chain links may be used for distributing address data, or may be used for distributing an enable signal that allows an IC to store address data provided on the shared bus.

Apparatus and methods for initializing integrated circuit addresses

Switchable power domains for 1.2V and 3.3V pad voltages

A signal generator is disclosed. The signal generator includes a variable frequency selector that is configured to provide a variable frequency for generation of a variable frequency signal. The signal generator also includes a periodic signal generator. The periodic signal generator is used to generate a periodic signal. The periodic signal generator has an input receiving the variable frequency signal and an output providing the periodic signal. The periodic signal has a frequency approximately the same as the variable frequency selection. The periodic signal generator stores a table of values associated with a reference periodic signal, each stored value corresponding to a discrete time in the reference periodic signal. The periodic signal generator is configured to interpolate between the discrete points in the table of derivative values.

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Costa Mesa, CA, United States of America

Daniel Schoch