Motorola Corporation

International Business Machines Corporation

Freescale Semiconductor,inc.

David D Barrera

Paul C Rossbach

Bahador Rastegar

Gary L Miller

Michael E Gladden

Don-Sun Min

Bahador Rastegar, Deceased

Md H Taufique

Dave Levitan

A source clock signal is received from a primary semiconductor device by a secondary semiconductor device via an interconnect. A local clock signal is generated on the secondary semiconductor device based on the source clock signal. A mode control signal is generated on the secondary semiconductor device, where the mode control signal indicates one of an unlock mode of operation and a lock mode of operation of the secondary semiconductor device. A physical interface (PHY) clock signal is generated based on the local clock signal, where the PHY clock signal includes the local clock signal during the lock mode, and the PHY clock signal includes an inverted version of the local clock signal during the unlock mode. Data received from the primary semiconductor device via the interconnect is latched at a positive edge of the PHY clock signal during the unlock mode and the lock mode.

Synchronous communication between system in package (SiP) devices

An integrated circuit is disclosed that includes a first signal line adjacent to a second signal line. A first latch is coupled between the first and second signal line. The first latch includes a first transistor having a first current electrode coupled to the first signal line and a control electrode coupled to the second control line and a second transistor having a first current electrode coupled to the second signal line and a control electrode coupled to the first signal line. The first signal line typically runs substantially parallel to the second signal line. A signal generator circuit may be coupled to a first end of the first and second signal lines and a receiver circuit may be coupled to a second end of the first and second signal line. The first latch may be coupled closer to the second end of the first and second signal lines than the first end of the first and second signal lines. In one embodiment, the signal generator circuit comprises a precharge circuit that precharges the first and second signal lines to a predetermined voltage such as a low state or a high state. The circuit may include additional signal lines and additional latches where a latch is coupled between each pair of adjacent signal lines. In an embodiment in which the latch transistors are NMOS transistors, the second current electrodes of each of the transistors is coupled to a ground node. The signal lines may comprise the word lines of a semiconductor memory.

Method and apparatus for coupling noise reduction in a semiconductor device

A cache memory uses content-addressable tag-compare arrays (CAM) to determine if a match occurs. In a semi-associative instruction cache, with the CAM and eight cache lines grouped together to form camlets, a binary index is used to address one camlet in the cache array, and the effective address tag match is used to select a potential line within the camlet in accessing data stored in the cache array. Since an E-tag match causes that cache line's wordline to activate, proper cache operation requires that no two (or more) E-tags within a camlet have the same match criteria (ECAM entry); the invalidation of entries is done to prevent this from happening. Due to the mapping of the effective address into the E-tag CAM and the camlet binary index, addresses that are 1-Meg apart point to the same camlet and have the same ECAM tag. The method thus employs a semi-associative cache having cache lines configured in camlets of, for example, eight lines per camlet. An LRU indication is stored in each camlet showing which line was least-recently-used. Upon occurrence of a cache replacement operation, it is determined whether or not a replacement line has a tag matching a line that is already in the camlet, and, if so, this line is invalidated and it is indicated to be the least-recently-used line. The next replacement goes to this line, whereas otherwise it would have appeared to be the most-recently-used since its wordline went high for the invalidate operation.

Semi-associative cache with MRU/LRU replacement

A memory cache (14) has a semi-associative cache array (50), a cache reload buffer (40), and a cache reload buffer driver (42). The memory cache writes received data to the cache reload buffer and waits until the data is requested again before it invalidates any cache aliased entries in the semi-associative cache array. This invalidation step requires no dedicated cycle but instead is a result of the memory cache being able to simultaneously read from the semi-associative cache array and the cache reload buffer.

Memory cache with automatic alliased entry invalidation and method of

A memory cache (14) has a plurality of cache lines (50) for storing a series of contiguous memory elements. Each series of memory elements are interlaced within the corresponding cache line on a element-by-element basis and on a bit-by-bit basis. This storage strategy allows the memory cache to output a subset memory elements within a cache line quickly and in the original contiguous order. The invention may be advantageously incorporated in an instruction cache of superscalar data processor to provide a series of sequential instructions for execution.

Growing community of inventors

Austin, TX, United States of America

David D Barrera