Abstract: A method of selecting CAS latencies in a system. Specifically, a system which includes a plurality of memory devices and a memory controller is provided. Because different memory devices may have different CAS latencies, a system CAS latency is selected wherein the system CAS latency is the fastest common CAS latency of each of the plurality of memory devices. After a read request is delivered to a memory device, the memory controller initiates a transmission flag to the memory device at a time equal to the system CAS latency, indicating that it is safe to transmit the requested data from the memory device to the memory controller. The transmission flags may be used in conjunction with mode registers such that one or both of the transmission flag and the data may be received by or delivered by a corresponding memory device.

Abstract: A computer system includes a system controller that has configuration storage to store information to indicate whether the system controller is to associate tag information with a memory access request, and to indicate whether debug information or device identification information is to be encoded in the tag information.

Abstract: A computer system includes a processor bus, a system bus, a memory bus and a system controller. The system controller is adapted to programmatically tag memory access requests to indicate a characteristic of the receiving interface or a characteristic of the requesting device. Characteristics of the receiving interface include internal interface state information such as current length of input and output queue structures. Characteristics of the requesting device include whether the device is a burst oriented or a non-burst oriented memory access device.

Abstract: A method for use with a computer system includes permitting a first bus agent to access a bus during predetermined windows of time and preventing a second bus agent from accessing the bus outside of the windows. The first bus agent has a higher priority than the second bus agent. The method includes monitoring the use of the bus by the first bus agent during the window and the regulation durations of the windows are selectively regulated based on the use.

Abstract: One embodiment of the present invention provides a system for synthesizing a circuit that allocates propagation delay between modules in the circuit based upon wireload information. The system receives a circuit divided into modules coupled together by a number of signal lines. The system defines a first set of timing constraints, and uses the first set of timing constraints to compile the circuit from a hardware description language specification into a first gate-level implementation. Next, the system performs a timing analysis on the first gate-level implementation to determine positive or negative slack values for the signal lines. These slack values specify amounts of extra propagation delay available on the signal lines. Next, the slack values are used to define a second set of timing constraints by allocating the slack values between the modules based upon wireload information.

Abstract: A computer system includes a system controller that has configuration storage to store information to indicate whether the system controller is to associate tag information with a memory access request, and to indicate whether debug information or device identification information is to be encoded in the tag information.

Abstract: A computer system includes a memory bus, a memory device and a bridge. The memory device is adapted to furnish a data strobe signal to the memory bus and furnish other signals (to the memory bus) that are indicative of data. The bridge includes a first circuit that is adapted to use the other signals to capture the data in response to the data strobe signal. A second circuit of the bridge is coupled to the first circuit and is adapted to receive a data strobe signal from a memory bus. The data strobe signal is furnished by the memory device and includes a postamble. The second circuit is also adapted to monitor the data strobe signal to detect a signature of the data strobe signal that precedes the beginning of the postamble and prevent the first circuit from responding to the data strobe signal after detection of the signature.

Abstract: A method and system transfer read data from a memory device having a data bus and a data masking pin adapted to receive a masking signal during write operations of the memory device. The method includes placing a sequence of read data words on the data bus and applying a data bus inversion signal on the data masking pin, the data bus inversion signal indicating whether the data contained each read data word has been inverted. Another method and system transfer data over a data bus. The method includes generating a sequence of data words, at least one data word including data bus inversion data. The sequence of data words is applied on the data bus and is thereafter stored. The data bus inversion data is applied to invert or not invert the data contained in the stored data words.

Abstract: A method and system masking data being written to a memory device having a data bus. One method includes applying masking data on the data bus, storing the masking data in the memory device, applying write data on the data bus, storing the write data in the memory device, and applying the stored masking data to mask the stored write data.

Abstract: A memory system and method according to various aspects of the present invention comprises a memory and an adaptive timing system for controlling access to the memory. The adaptive timing system captures data in a data valid window (DVW) in a data signal. In one embodiment, the adaptive timing system comprises a delay circuit for sampling the data signal at a midpoint of the DVW. The adaptive timing system may also comprise an identifying circuit for identifying whether the midpoint of the DVW corresponds to an actual midpoint of the DVW and adjusting the delay circuit accordingly.

Abstract: An electronic system according to various aspects of the present invention includes a memory having a location-specific command interface and a general command interface. The memory communicates with other components in the system via a main command bus configured to transfer address-specific commands and a supplementary command bus configured to transfer general commands. Commands may be received by the memory simultaneously at the respective interfaces.

Abstract: An electronic system according to various aspects of the present invention includes a memory module configured to operate in multiple modes. The memory module includes at least one connection configured to perform different functions when the memory module is operating in different modes. In one embodiment, the memory operates in a normal mode and an SPD mode. While in SPD mode, the connection performs one or more SPD functions, such as operating as an SMBus interface connection. In normal mode, the connection serves a function associated with normal operation of the module, such as addressing functions.

Abstract: An application specific integrated circuit has at least one standard cell, integrated circuit connection circuitry connected to the at least one standard cell and at least one programmable circuit that is connected or selectively connectable to the integrated circuit connection circuitry. The selected connection is made by metal mask changes if and when it is desirable to change the logic of the application specific circuit. The programmable circuit is a general-purpose logic block and may be reprogrammed to effect design changes.

Abstract: A technique for reducing the latency associated with a memory read request. A bypass path is provided to direct the address of a corresponding request to a memory controller. The memory controller initiates a speculative read request to the corresponding address location. In the meantime, the original request is decoded and directed to the targeted area of the system. If the request is a read request, the memory controller will receive the request, and after comparing the request address to the address received via the bypass path, the memory controller will cancel the request since the speculative read has already been issued. If the request is directed elsewhere or is not a read request, the speculative read request is cancelled.

Abstract: A configuration register used to adjust a clock or request signal with respect to the other. Specifically, a look-up table is provided in the memory controller. The look-up table is filled at bootup such that it contains test information from a master look-up table in the system BIOS, for instance. The look-up table in the memory controller stores current test data correlative to optimal sampling times for the current configuration. Adjustable delay elements or adjustable load elements may be used to change the relative sampling time of the request signal correlative to the values stored in the memory controller look-up table.

Abstract: A method of selecting CAS latencies in a system. Specifically, a system which includes a plurality of memory modules is provided. Because different memory modules may have different CAS latencies, multilevel signaling is used to standardize the CAS latencies throughout the system. A static pin is provided on each memory device such that a drive signal can be received. The voltage level of the drive signal corresponds to a selected CAS latency for the system.

Abstract: A memory for storing address translation data includes one or more page table entry structures. Each page table entry structure includes a base address field to identify an allocated page of memory, a prior page field to identify zero or more allocated pages of memory that are sequential to and before that page of memory identified by the base address field, and a subsequent page field to identify zero or more allocated pages of memory that are sequential to and after that page identified by the base address field.

Abstract: A method for use with a computer system includes receiving a first data strobe signal from a bus and introducing a delay to the first data strobe signal to produce a second data strobe signal. The method includes determining whether the delay is within a predetermined range of delays, and if not, the method includes adjusting the delay to cause the delay to be within the predetermined range. The second data strobe signal is used to capture data from the bus.

Abstract: A computer system includes a memory device including banks, and a memory interface coupled to the memory device. The memory interface is adapted to store requests that are associated with the banks. At least two of the requests are copending. The memory interface is adapted to determine whether the banks associated with the copending requests are idle and execute the requests based on the determination.

Abstract: The present invention comprises a host bus clocked in a host clock domain, a secondary bus for receiving a reset command clocked in a secondary bus clock domain and a controller for dynamically delaying transactions on the host bus until the secondary bus is out of reset.