A method and circuit adaptively adjust the timing offset of a digital signal relative to a clock signal output coincident with that digital signal to enable a latch receiving the digital signal to store the digital signal responsive to the clock signal. The digital signal is applied to the latch, and stored in the latch responsive to the clock signal. The digital signal stored in the latch is evaluated to determine if the stored digital signal has an expected value. The timing offset of the digital signal is thereafter adjusted relative to the clock signal. and the digital signal is once again stored in the latch responsive to the clock signal at the new timing offset. A number of digital signals at respective timing offsets relative to the clock signal are stored and evaluated, and a final timing offset of the digital signal is selected from the ones of the timing offsets that cause the latch to store the digital signal having the expected value. The timing offset of the digital signal is thereafter adjusted to the selected final timing offset. A read synchronization circuit may adaptively adjust the timing offset of digital signals in this manner, and such a read synchronization circuit may be utilized in many types of integrated circuits, including packetized dynamic random access memories, memory systems including a memory controller and one or more such packetized dynamic random access memories, and in computer systems including a plurality of such packetized dynamic random access memories.

Method and apparatus for adaptively adjusting the timing offset between a clock signal and digital signals transmitted coincident with that clock signal, and memory device and system using same

Large capacity memory systems are constructed using stacked memory integrated circuits or chips. The stacked memory chips are constructed in such a way that eliminates problems such as signal integrity while still meeting current and future memory standards.

Methods and apparatus of stacking DRAMs

A integrated circuit, such as a memory integrated circuit, includes a vernier clock adjustment circuit receiving an input clock signal and providing a rising-edge clock signal representing the input clock signal delayed by a rising-edge delay and providing a falling-edge clock signal representing the input clock signal delayed by a falling-edge delay. An edge triggered circuit receives data and the rising-edge and falling-edge clock signals, and stores data at the rising-edge of the rising-edge clock signal and at the falling-edge of the falling-edge clock signal. One form of the invention is a memory system having a memory controller coupled to memory modules through data and command busses. Each memory module includes the vernier clock adjustment circuitry.

Clock vernier adjustment

A method and apparatus is disclosed for sensing the resistance state of a Programmable Conductor Random Access Memory (PCRAM) element using complementary PCRAM elements, one holding the resistance state being sensed and the other holding a complementary resistance state. A sense amplifier detects voltages discharging through the high and low resistance elements to determine the resistance state of an element being read.

Complementary bit PCRAM sense amplifier and method of operation

In one embodiment, the invention is a 64 bit hardware ID (H/W ID) for tying a software product to a particular computer to prevent software piracy. The 64 bit hardware ID represents ten different components of the user's computer: the CD-ROM device, the disk adapter, the disk device, the display adapter, the first drive serial number, the MAC address, the processor serial number, the processor type, the RAM size in Mb, and the SCSI adapter. Each time the software product is opened, the expanded H/W ID is compared to the hardware on the computer to determine whether a predetermined minimum number of components match. In one embodiment, the expanded H/W ID allows for expansion of the user's computer because so long as the component originally listed in the expanded H/W ID can be found on the computer, then that component matches the expanded H/W ID. Typically, seven out of ten components in the expanded H/W ID must match the computer before the software product will fully operate.

Hardware ID to prevent software piracy

An automated, portable, and time conservative memory test system for identifying test parameters including type, control line configuration, depth, width, access time, and burst features of any one of a wide variety of synchronous memories including SDRAMs and SGRAMs, and whether an IC chip, bank, board or module, without requiring hardware, modifications or additions to the memory device being identified, and without requiring storage of test patterns or characterizing data in the memory device. The tester is comprised of a 32-bit RISC CPU (80) in electrical communication with address/data/control bus (82) and with processor clock (84) which provides timing for the CPU. ROM (90) provides a non-volatile storage for all memory test system operating software programs, and RAM (93) provides temporary and intermediate storage for software programs.

Synchronous memory test system

A distributed tester method and system communicates test recipes for testing electronic devices from a host computer over a network to a test site. The test site translates test recipes into test instructions for execution by a test engine that determines the status of the electronic device. For instance, in a tester for testing memory, a test recipe is defined and stored with a host computer to determine test data for storage on the memory device under test at the test site. The host computer controls execution of the test recipe over the network. The test recipe is defined and stored in an XML formatted data file transmitted over the network to a processor at the test site. The test site processor translates the XML formatted data into test instructions for execution by a test engine. The test engine determines whether the memory device under test accurately stores data and provides the results, such as erroneously stored data, to the host computer through the network. A test design host and a global data master also interface with the network to aid the design and storage of test recipes. The distributed test method and system advantageously improves flexibility of testing over a geographically disbursed area and with divergent test recipes and devices under test.

Method and system for distributed testing of electronic devices

An automated, portable, and time conservative memory test system for identifying test parameters including type, control line configuration, depth, width, access time, and burst features of any one of a wide variety of synchronous memories including SDRAMs and SGRAMs, and whether an IC chip, bank, board or module, without requiring hardware modifications or additions to the memory device being identified, and without requiring storage of test patterns or characterizing data in the memory device.

Synchronous memory tester

A digital programmable delay which provides a series of pulses that are programmed in both pulse latency and trigger latency to control the operation of a memory module test system.

Programmable pulse generator

A time conserving method of identifying width, depth, access time, control line configurations, and part type of any of a plurality of different synchronous memories. A nested loop process is used to develop, and apply to a synchronous memory being identified, trial control line configurations taken from ordered entries of tables representative of the plurality of synchronous memories. The width, depth, control line configurations, and part type are determined from the responses evoked from the synchronous memory being identified. The delay between a read command issued by the test system CPU and a reading of bit patterns from the synchronous memory is incremented in finite steps in successive write/read iterations until the bit pattern read is identified to the bit pattern written into the synchronous memory, thereby identifying the access time of the synchronous memory.

Jack C. Little

Papers

Synchronous memory test system

Method and system for distributed testing of electronic devices

Synchronous memory tester

Programmable pulse generator

Method and system for automatic synchronous memory identification