Abstract: The present invention provides for reducing current spikes in a circuit when changing clocking frequencies. A first frequency is applied to a clock distribution network. A final frequency is selected. The first frequency is applied to a logic element over the clock distribution network. A hold signal is applied to the logic element. The clock rate of the clock distribution network is changed from the first frequency to the final frequency. The hold signal is unapplied to the logic element.

Abstract: The present invention provides for reducing current spikes in a circuit when changing clocking frequencies. A first frequency is applied to a clock distribution network. A final frequency is selected. The first frequency is applied to a logic element over the clock distribution network. A hold signal is applied to the logic element. The clock rate of the clock distribution network is changed from the first frequency to the final frequency. The hold signal is unapplied to the logic element.

Abstract: The present invention provides for reducing current spikes in a circuit when changing clocking frequencies. A first frequency is applied to a clock distribution network. A final frequency is selected. The first frequency is applied to a logic element over the clock distribution network. A hold signal is applied to the logic element. The clock rate of the clock distribution network is changed from the first frequency to the final frequency. The hold signal is unapplied to the logic element.

Abstract: A system and method for testing functional boundary logic at an asynchronous clock boundary of an integrated circuit device. With the system and method, each clock domain has its own scan paths that do not cross domain boundaries. By eliminating the scanning across the boundaries, the requirement to have two clock grids in the asynchronously clocked domains may be eliminated. As a result, circuit area and design time with regard to the clock distribution design are reduced. In addition, removing the second clock grid, i.e. the high speed core or system clock, in the asynchronously clocked domains removes the requirement to have a multiplexing scheme for selection of clocking signals in the asynchronous domain. In addition to the above, the system and method provide boundary built-in-self-test logic for testing the functional crossing logic of boundaries between the clock domains in a functional mode of operation.

Abstract: A method and apparatus for loading a ring of non-scan latches for a logic built-in self-test. A logic built-in self-test value is loaded into a scannable latch from the logic built-in self-test. An override control signal is asserted in response to loading the logic built-in self-test value into the scannable latch. A non-scan latch is forced to load the logic built-in self-test value from the scannable latch in response to asserting the override control signal. Logic paths in the ring of non-scan latches are exercised. The non-scan latch is part of the logical paths. The test results are captured from the logic paths and the test results are compared against expected test results to determine if the logic paths within the ring of non-scan latches are functioning properly.

Abstract: A method and apparatus are disclosed for injecting errors in the functional units of a processor system, and for observing non-injected errors that occur in those functional units. A local error handler layer provides error injection for the various functional units at a local level. A global fault isolation register (FIR) layer couples to the local error handler layer to coordinate the handling of local errors in the multiple functional units of the processor system. A software debugger application or system software communicates with the global FIR layer to control error handling.

Abstract: Systems and methods for performing logic built-in self-tests (LBISTs) in which an LBIST controller provides control signals to multiple LBIST satellites that are co-located with different functional blocks of the device under test, such as processor cores in a multiprocessor integrated circuit. Because the data paths for each satellite are shorter than data paths in conventional LBIST architectures, fewer latches are needed to synchronize the delivery of data to scan chains in the satellites. In one embodiment, each satellite includes a pseudorandom bit pattern generator (PRPG,) scan chains and a multiple-input signature register (MISR). In one embodiment, the LBIST circuitry also includes a control scan chain that is coupled to each of the LBIST satellites and configured to scan data into and out of the LBIST satellites.

Abstract: A clock control hierarchy is provided that is comprised of synchronous and asynchronous hold request signals that are used to start and stop functional units of a chip. Pervasive logic is provided that uses a synchronous “chip hold” signal and asynchronous latch/functional unit hold signals to individually target functional units and latches that are to remain in a held state once the “chip hold” state is released. With the present invention, a chip hold request is first activated followed by scannable latch and non-scannable latch hold requests being activated to identify which latches will be clocked or not clocked when the chip hold is released. Functional unit hold signals are activated to place certain ones of the functional units of the chip in a hold state. The chip hold request is deactivated and the chip operates with the selected functional units and latches being maintained in a held state.

Abstract: Methods and apparatus provide for: producing a control signal at a first substantially steady state logic level indicative of a sleep mode, and at a second substantially steady state logic level indicative of a normal mode; producing a gate signal that is at a substantially steady state null level when the control signal is at the first logic level, and that oscillates at a local clock frequency when the control signal is at the second logic level; producing a local clock signal from a system clock signal as a function of the gate signal; and interposing at least one signal propagation latch circuit between an origin of the control signal and the location at which the gate signal is produced.

Abstract: Systems and methods for performing logic built-in self-tests (LBISTs) in digital circuits, where boundary scan chains in functional blocks of the circuits can be selectively coupled/decoupled to isolate the functional blocks during LBIST testing. In one embodiment, processor cores of a multiprocessor chip are isolated and LBIST testing is performed to determine whether any of the processor cores is malfunctioning. If none of the processor cores malfunctions, the processor cores are tested in conjunction with the supporting functional blocks of the device to determine whether the multiprocessor is fully functional. If one or more processor cores malfunctions, these processor cores are isolated and the remaining processor cores are tested in conjunction with the supporting functional blocks of the device to determine whether the multiprocessor operates properly with reduced functionality.

Abstract: The present invention provides a data processing system, a method, and a computer program product for stopping at least two clock signals that oscillate at different frequencies and restarting the at least two clock signals at their correct phase. A RUNN counter stops the at least two clock signals. The RUNN counter stops the faster clock signal and restarts the faster clock signal at the correct phase. A phase status circuit determines the phase where the slower clock signal stopped and produces a phase status signal. A second circuit utilizes the phase status signal to start the slower clock signal at the correct phase. Therefore, the present invention insures that the faster clock signal and the slower clock signal are restarted at the correct phase. In another embodiment, the second circuit enables the present invention to start the slower clock signal at a desired phase.

Abstract: An apparatus and method for controlling asynchronous clock domains to perform synchronous operations are provided. With the system and method, when a synchronous operation is to be performed on a chip, the latches of the functional elements of the chip are controlled by a synchronous clock so that the latches are controlled synchronously even across asynchronous boundaries of the chip. The synchronous operation may then be performed and the chip's functional elements returned to being controlled by a local clock in an asynchronous manner after completion of the synchronous operation. This synchronous operation may be, for example, a power on reset (POR) operation, a manufacturing test sequence, debug operation, or the like.

Abstract: An apparatus and method for using electrical fuses (eFuses) to store phase-locked loop (PLL) configuration data are provided. With the apparatus and method, a portion of the eFuses present in the integrated circuit are reserved for the PLL configuration data. Upon power up, a power up controller and eFuse controller direct the sensing and serial transfer of the data in the portion of eFuses to the PLL under the reference clock. When the transfer is complete, the power up controller directs the PLL logic to load the configuration data and start. The mechanism of the present invention allows manufacturing to tailor the PLL configuration on a given device based on the characteristics of that device and its intended usage. Thus, the same PLL may be used in the same or different architectures to perform different operations based on the configuration data passed into the PLL from the eFuses.

Abstract: The present invention provides for reducing current spikes in a circuit when changing clocking frequencies. A first frequency is applied to a clock distribution network. A final frequency is selected. The first frequency is applied to a logic element over the clock distribution network. A hold signal is applied to the logic element. The clock rate of the clock distribution network is changed from the first frequency to the final frequency. The hold signal is unapplied to the logic element.