摘要:
In one embodiment, a timing slave packet switching device receives a received primary reference clock signal. The timing slave packet switching device communicates a first plurality of packet network synchronization packets over a packet switching network with a remote primary reference clock source and derives an over-network clock based on the first plurality of packet network synchronization packets. A phase offset between the phase of the over-network clock and the phase of the received primary reference clock signal is determined and typically stored in non-volatile storage. Subsequent to said determining the phase offset, the timing slave packet switching device communicates a second plurality of packet network synchronization packets over the packet switching network with the remote primary reference clock source and adjusts the phase of a clock derived from the second plurality of packet network synchronization packets based on the phase offset.
摘要:
In one embodiment, a timing slave packet switching device receives a received primary reference clock signal. The timing slave packet switching device communicates a first plurality of packet network synchronization packets over a packet switching network with a remote primary reference clock source and derives an over-network clock based on the first plurality of packet network synchronization packets. A phase offset between the phase of the over-network clock and the phase of the received primary reference clock signal is determined and typically stored in non-volatile storage. Subsequent to said determining the phase offset, the timing slave packet switching device communicates a second plurality of packet network synchronization packets over the packet switching network with the remote primary reference clock source and adjusts the phase of a clock derived from the second plurality of packet network synchronization packets based on the phase offset.
摘要:
A system for on-chip testing of embedded memories using Address Space Identifier (ASI) bus in Scalable Processor ARChitecture (SPARC) microprocessors. An integrated circuit includes a plurality of memory arrays, Address Space Identifier (ASI) bus interface logic connected by an ASI bus to the plurality of memory arrays, and a memory control unit and a memory built-in self-test (MBIST) engine connected to the ASI bus interface logic. Rather than direct access, the MBIST engine utilizes the ASI bus interface logic and the ASI bus to perform memory testing. The MBIST engine, programmed with memory array parameters, includes a programmable state machine controller to which is connected a programmable data generator, a programmable address generator, and a programmable comparator. The data generator provides data as appropriate. The address generator provides addresses as appropriate. The comparator provides test results information for the particular test situation. The MBIST engine generates a test status output.
摘要:
A boundary scan cell design which places the multiplexor before the functional flip-flip on the functional line path, reducing the multiplexor delay in the critical path. This optimizes the multiplexor and functional flip-flop orientation, allowing for a significant reduction in the time required from output of the functional flip-flop to a pin or to the interior of the CPU (the clock to q delay). In order to ensure that boundary scan mode functions properly, the functional flip-flop may be designed to act as a buffer, i.e. become transparent, when the boundary scan cell is in boundary scan mode.
摘要:
A boundary scan cell design which places the multiplexor before the functional flip-flip on the functional line path, reducing the multiplexor delay in the critical path. This optimizes the multiplexor and functional flip-flop orientation, allowing for a significant reduction in the time required from output of the functional flip-flop to a pin or to the interior of the CPU (the clock to q delay). In order to ensure that boundary scan mode functions properly, the functional flip-flop may be designed to act as a buffer, i.e. become transparent, when the boundary scan cell is in boundary scan mode.
摘要:
A method and apparatus for test of asynchronous pipelines. An asynchronous data pipeline includes first and second pluralities of pipeline stages in an alternating sequence. Each of the pipeline stages includes a control circuit, a latch circuit configured to latch data responsive to an indication from the control circuit, and a combinational logic circuit coupled to receive data from an output of the latch circuit. Each of the latch circuits is scannable. The latch circuits of the first and second pluralities of pipeline stages form a data scan chain configured to load test data into the combinational logic circuits during testing of the data pipeline. The data pipeline further includes a control scan chain configured to load control data for operating the control circuits during testing of the data pipeline. Testing of the data pipeline can include independent testing of the control portion or the data portion.
摘要:
A method and system for testing a chip at functional (operational) speed. The chip may include an integrated circuit having a number flops and memory arrays arranged into logically functioning elements. Additional flops may be included to output to one or more of the other flops in order to provide inputs to the flops at the functional speed such that the receiving flops executing at the functional speed according to the received input at a next functional clock pulse to facilitate testing the chip at the functional speed.
摘要:
A method and apparatus for conveying test response data from an integrated circuit to ATE via a plesiochronous interconnect. The integrated circuit includes a core logic unit and a first transmitter coupled thereto by a first data path. In a normal mode, data conveyed from the core logic unit to the transmitter may be transmitted plesiochronously over an interconnect coupled to the transmitter output. The integrated circuit further includes a second data path coupled between the core logic unit and the interconnect. During a test mode, test response data may be conveyed from the core logic unit to ATE via the second data path and the interconnect, wherein the test response data is synchronously transmitted over the interconnect.
摘要:
A method of testing chips for manufacturing defects or operational based defects. The method may be used with any chip having logically function elements, including chips having multiple cores configured to be physically and logically identical. The method may be used to limit the total number of bits required to test the cores by demultiplexing and/or compacting the bits provided to the cores and/or outputted from the cores during a scan test.
摘要:
A method and circuit for capturing and observing the internal state of an integrated circuit that utilizes a scan chain capable of capturing the functional state of an integrated circuit during functional testing without interrupting the functional testing. The functional state may be captured by and shifted out of the scan chain concurrently with functional testing. The scan chain includes sequential elements, each having a functional state and a scan state that operate in parallel. The method and circuit may further include a signature analyzer for compressing the contents of the scan chain into a signature. The method and circuit may capture and compress multiple functional states into a combined signature.