Philips Electronics North America Corporation

Koninklijke Philips Corporation N.V.

William W Kolb

William J Silvkoff

Jie Zheng

Jerry Hongbin Hao

Hartmut Karl Habben

Frank S Lee

A memory interface unit for coupling a microprocessor to a memory external to the microprocessor. The memory comprises a plurality of memory banks of mixed type, generic memory banks such as ROM, EPROM, or the like, which are directly addressable, and DRAM memory banks, which are addressable by row and column addresses, validated by row and column strobes. The memory interface provides unique strobes for each of the memory banks, which are programmable in dependence of the type of memory bank to which a particular strobe relates. The unique strobes are programmable so as to support both generic memory and DRAM, as the case may be.

Memory interface unit with programmable strobes to select different memory devices

A pulse edge detector for detecting edges of a pulse signal in a bit stream. The bit stream, and herewith the pulse signal, is synchronized to a clock having half the resolution of a clock signal used to transmit the bit stream. Falling and rising edges of the synchronized pulse signal are determined. It is further determined whether the falling and rising edges of the pulse signal fall within a first or a second phase of the clock signal. The determined phase result is recorded for further processing by a succeeding circuit such as a counter. By determination of the pulse phase in both phases of the clock pulse, a double resolution pulse edge detector is obtained.

Pulse detector with double resolution

A FIFO unit for buffering serial communications includes a register and a unit for maintaining a single pointer. The single pointer functions as an IN pointer during writes and an OUT pointer during reads. The same circuitry maintains the pointer for both reads and writes to the FIFO. This circuitry preferably includes a single counter. If an error occurs during reading, the single pointer can be reinitialized and reading restarted, without loss of data. The register is not erased until reading is complete.

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Sunnyvale, CA, United States of America

William W Kolb