Abstract: A delay locked loop (DLL) having an accelerated training interval during a voltage change. An integrated circuit (IC) includes a master DLL configured to generate a clock signal based upon a reference clock signal. The master DLL may train to the reference clock signal in response to a control signal. The IC also includes a control unit that is coupled to the master DLL and may provide the control signal at a first interval in response to receiving an indication that a supply voltage is being changed, and provide the control signal at a second interval in the absence of the indication.

Abstract: Systems and methods for coordinating performance parameters in multiple domains are described. In an embodiment, a method includes receiving a request to change a state of an electronic circuit, where the circuit includes a first domain and a second domain, causing a first parameter of a first circuit serving the first domain to be modified to a first modified parameter based on the request, and causing a second parameter of a second circuit serving the second domain to be modified to a second modified parameter based on the request. In some cases, a parameter may include a clock frequency. In other cases, a parameter may include a voltage. In some embodiments, a system may be implemented as a logic circuit and/or as a system-on-a-chip (SoC). Devices suitable for using these systems include, for example, desktop and laptop computers, tablets, network appliances, mobile phones, personal digital assistants, e-book readers, televisions, and game consoles.

Abstract: A direct memory access (DMA) engine schedules data transfer requests of a data processing system according to both an assigned transfer priority and the deadline for completing a transfer.

Abstract: Adjusting a clock source of a device clock to reduce wireless communication (e.g., radio frequency (RF)) interference within a device. The device clock may be derived from an input clock to a serial interface, e.g., coupled to a display, and may be initially driven by a first clock. Later, it may be determined that the serial interface clock is or will interfere with wireless communication. Accordingly, temporary clock signals may be provided to the device clock while the first clock is modified. Once modified, the modified clock signals may be provided to the device clock to reduce wireless communication interference.

Abstract: In one embodiment, an interrupt controller may implement an interrupt distribution scheme for distributing interrupts among multiple processors. The scheme may take into account various processor state in determining which processor should receive a given interrupt. For example, the processor state may include whether or not the processor is in a sleep state, whether or not interrupts are enabled, whether or not the processor has responded to previous interrupts, etc. The interrupt controller may implement timeout mechanisms to detect that an interrupt is being delayed (e.g. after being offered to a processor). The interrupt may be re-evaluated at the expiration of a timeout, and potentially offered to another processor. The interrupt controller may be configured to automatically, and atomically, mask an interrupt in response to delivering an interrupt vector for the interrupt to a responding processor.

Abstract: A global timebase system and method for a system-on-chip synchronizes multiple clock domains in each of a plurality of receiver modules by broadcasting a global timebase count value as Gray code over a global timebase bus. A global timebase generator includes a binary counter and a binary-to-Gray-code converter. Each receiver module registers the global timebase count value with its own local clock and includes a Gray-code-to-binary converter. The converted value, in binary form, may be used as least significant bits of a globally synchronized local timebase. Most significant bits may be generated by a local binary counter incremented at each 1-to-0 transition of the most significant bit of the global timebase count value.

Abstract: An efficient delay locked loop (DLL) training protocol during a frequency change includes an integrated circuit with a memory physical layer (PHY) unit that includes a master DLL and a slave DLL. The master DLL may delay a first reference clock by an amount, and provide a reference delay value corresponding to the delay amount. The slave DLL may delay a second reference clock by a second amount based upon a received configuration delay value. An interface unit may generate the configuration delay value based upon the reference delay value. A power management unit may provide an indication that the frequency of the second reference clock is changing. In response to receiving the indication, the interface unit may generate a new configuration delay value that corresponds to the new frequency using a predetermined scaling value and provide the new configuration delay value to the memory PHY unit.

Abstract: A delay locked loop (DLL) having an accelerated training interval during a voltage change. An integrated circuit (IC) includes a master DLL configured to generate a clock signal based upon a reference clock signal. The master DLL may train to the reference clock signal in response to a control signal. The IC also includes a control unit that is coupled to the master DLL and may provide the control signal at a first interval in response to receiving an indication that a supply voltage is being changed, and provide the control signal at a second interval in the absence of the indication.

Abstract: An apparatus and method for changing the extra margin adjustment (EMA) for a memory is disclosed. A control unit may access a table responsive to an indication of a change of operating point. The table includes a number of different delay times, each of which corresponds to a particular operating point. The control unit may select the delay time that corresponds to the new operating point to which the memory operation is being changed. The control unit may further convey an indication of the selected delay time to the memory, thereby causing the memory to operate according thereto.

Abstract: In an embodiment, a control circuit is configured to transmit operations to a circuit block that is being powered up after being powered down, to reinitialize the circuit block for operation. The operations may be stored in a memory (e.g. a set of registers) to which the control circuit is coupled. In an embodiment, the control circuit may also be configured to transmit other operations from the memory to the circuit block prior to the circuit block being powered down. Accordingly, the circuit block may be powered up or powered down even during times that the processors in the system are powered down (and thus software is not executable at the time), without waking the processors for the power up/power down event. In an embodiment, the circuit block may be a cache coupled to the one or more processors.

Abstract: A direct memory access (DMA) engine schedules data transfer requests of a system-on-chip data processing system according to both an assigned transfer priority and the deadline for completing a transfer. Transfer priority is based on a hardness representing the penalty for missing a deadline. Priorities are also assigned to zero-deadline transfer requests in which there is a penalty no matter how early the transfer completes. If desired, transfer requests may be scheduled in timeslices according to priority in order to bound the latency of lower priority requests, with the highest priority hard real-time transfers wherein the penalty for missing a deadline is severe are given the largest timeslice. Service requests for preparing a next data transfer are posted while a current transaction is in progress for maximum efficiency. Current transfers may be preempted whenever a higher urgency request is received.

Abstract: Methods for enabling a secure test mode, and integrated circuits (IC's) implementing the same are disclosed. An IC may include a secure functional unit that is protected from access from test access circuitry during normal operation. The secure functional unit may be rendered inaccessible the test access circuitry of the IC following a completion of a test that includes testing of the secure functional unit. An embodiment of an IC that includes circuitry to delay entry into a test mode while a chip-level reset is performed is also contemplated. Entry into the test mode may be delayed until all circuitry of the IC has been fully reset in order to clear stored information.

Abstract: Methods for enabling a secure test mode, and integrated circuits (IC's) implementing the same are disclosed. An IC may include a secure functional unit that is protected from access from test access circuitry during normal operation. The secure functional unit may be rendered inaccessible the test access circuitry of the IC following a completion of a test that includes testing of the secure functional unit. An embodiment of an IC that includes circuitry to delay entry into a test mode while a chip-level reset is performed is also contemplated. Entry into the test mode may be delayed until all circuitry of the IC has been fully reset in order to clear stored information.

Abstract: A multiply accumulate unit (“MAC”) that performs operations on packed integer data. In one embodiment, the MAC receives 2 32-bit data words which, depending on the specified mode of operation, each contain either four 8-bit operands, two 16-bit operands, or one 32-bit operand. Depending on the mode of operation, the MAC performs either sixteen 8×8 operations, four 16×16 operations, or one 32×32 operation. Results may be individually retrieved from registers and the corresponding accumulator cleared after the read cycle. In addition, the accumulators may be globally initialized. Two results from the 8×8 operations may be packed into a single 32-bit register. The MAC may also shift and saturate the products as required.

Abstract: A global timebase system and method for a system-on-chip synchronizes multiple clock domains in each of a plurality of receiver modules by broadcasting a global timebase count value as Gray code over a global timebase bus. A global timebase generator includes a binary counter and a binary-to-Gray-code converter. Each receiver module registers the global timebase count value with its own local clock and includes a Gray-code-to-binary converter. The converted value, in binary form, may be used as least significant bits of a globally synchronized local timebase. Most significant bits may be generated by a local binary counter incremented at each 1-to-0 transition of the most significant bit of the global timebase count value.

Abstract: A size and retry programmable multi-synchronous FIFO. In one embodiment, a multi-synchronous FIFO memory generally comprises a selectable number of addressable memory locations for storing information; read control means synchronized by a read clock for controlling pop transactions configured to read from one or more of the selected number of addressable memory locations; write control means synchronized by a write clock asynchronous to the read clock for controlling push transactions to write to one or more of the selected number of addressable memory locations; and selectable transaction retry control means configured to cause read control means to repeat selected pop transactions and/or cause write control means to repeat selected push transactions.

Abstract: A direct memory access (DMA) engine schedules data transfer requests of a system-on-chip data processing system according to both an assigned transfer priority and the deadline for completing a transfer. Transfer priority is based on a hardness representing the penalty for missing a deadline. Priorities are also assigned to zero-deadline transfer requests in which there is a penalty no matter how early the transfer completes. If desired, transfer requests may be scheduled in timeslices according to priority in order to bound the latency of lower priority requests, with the highest priority hard real-time transfers wherein the penalty for missing a deadline is severe are given the largest timeslice. Service requests for preparing a next data transfer are posted while a current transaction is in progress for maximum efficiency. Current transfers may be preempted whenever a higher urgency request is received.

Abstract: A method and system for DMA transfer of data in scatter/gather mode. A table of buffer descriptors may be used to determine the next buffer to be used when a current buffer storing data that has been transferred or will be transferred and may be used in automatic buffer switching, which does not require processor intervention. Entries in the table of buffer descriptors are entered programmatically. The method and system also provide for hardware writing to table of packet descriptors which describes location and size of incoming data and can indicate whether a packet of data straddles two or more buffers, thus decoupling packet sizes from buffer sizes.

Abstract: A multiply accumulate unit (“MAC”) that performs operations on packed integer data. In one embodiment, the MAC receives 2 32-bit data words which, depending on the specified mode of operation, each contain either four 8-bit operands, two 16-bit operands, or one 32-bit operand. Depending on the mode of operation, the MAC performs either sixteen 8×8 operations, four 16×16 operations, or one 32×32 operation. Results may be individually retrieved from registers and the corresponding accumulator cleared after the read cycle. In addition, the accumulators may be globally initialized. Two results from the 8×8 operations may be packed into a single 32-bit register. The MAC may also shift and saturate the products as required.