摘要:
A method and apparatus are provided for parallel addressing a CAM and a RAM, and also for using a single wordline to address the CAM and/or RAM. The CAM and RAM are addressed using a common wordline, and the common wordline is also used for writing to the CAM during a write cycle and strobing the CAM during a read cycle.
摘要:
A structure and method of operation of a cache memory are provided. The cache memory is organized such that the data on a given line of any page of the main memory is stored on the same line of a page of the cache memory. Two address memories are provided, one containing the first eight bits of the virtual address of the page of the data in main memory and the second the entire real page address in main memory. When an address is asserted on the bus, the line component of the address causes each of those lines from the cache memory to read out to a multiplexor. At the same time, the eight bit component of the virtual address is compared in the first memory to the eight bits of each line stored in the first memory, and if a compare is made, the data on that line from that page of cache memory is read to the CPU. Also, the entire real address is compared in the second memory, and if a match does not occur, the data from the cache to the CPU is flagged as invalid data. A structure and method are also provided to determine if duplicate addresses exist in the second address memory.
摘要:
An associated memory structure having a plurality of memories amenable for testing and a method of testing the memories is provided. First and second memories are formed, wherein data in the first memory provides a basis for at least a portion of the input to the second memory during functional operation of two memories. Preferably, an output latch for receiving the output test data from the first memory is provided. Means are provided for loading the first memory with data which is utilized as a basis for providing at least a portion of the input to the second memory. An access path from the output port of the first memory to the input port of the second memory allows use of the data in the first memory to generate at least a portion of the input to the second memory. The first memory is first tested independently of the second memory. Thereafter, the first memory is loaded with preconditioned data that is used as a basis for inputs to the second memory during testing of the second memory. The second memory is then tested by generating inputs to the first memory during testing of the second memory. Thus, outputs of the first memory constitute at least a portion of test data inputted to the second memory. A latch is provided to capture the output of the test data from the second memory.
摘要:
According to the present invention, a circuit and methods for enhancing the operation of SOI fabricated devices are disclosed. In a preferred embodiment of the present invention, a pulse discharge circuit is provided. Here, a circuit is designed to provide a pulse that will discharge the accumulated electrical charge on the body of the SOI devices in the memory subarray just prior to the first access cycle. As explained above, once the accumulated charge has been dissipated, the speed penalty for successive accesses to the memory subarray is eliminated or greatly reduced. With a proper control signal, timing and sizing, this can be a very effective method to solve the problem associated with the SOI loading effect. Alternatively, instead of connecting the bodies of all SOI devices in a memory circuit to ground, the bodies of the N-channel FET pull-down devices of the local word line drivers can be selectively connected to a reference ground. This would enable the circuit to retain most of the speed advantages associated with SOI devices while overcoming the loading problem described above. With this preferred embodiment of the present invention, the major delay caused by the bipolar loading effect is minimized while the speed advantage due to providing a lower, variable Vt effect is preserved. The overall body resistance of the individual devices has a minimal effect on the device body potential.
摘要:
A silicon-on-insulator (SOI) structure and method of making the same includes an SOI wafer having a silicon layer of an original thickness dimension formed upon an isolation oxidation layer. At least two p-type bodies of at least two SOI field effect transistors (PFETs) are formed in the silicon layer. At least two n-type bodies of at least two SOI field effect transistors (NFETs) are also formed in the silicon layer. Lastly, an SOI body link is formed in the silicon layer of the SOI wafer adjacent the isolation oxidation layer for selectively connecting desired bodies of either the p-type SOI FETs or the n-type SOI FETs and for allowing the connected bodies to float.