International Business Machines Corporation

Bruce W Singer

Frank David Ferraiolo

Timothy Jay Dell

Norman Jay Rohrer

John E Gersbach

Kamal Emile Dimitri

Bruce G Hazelzet

Charles Joseph Masenas

Marc Raymond Faucher

Kent A Dramstad

A memory card design which adds parity for non-parity computer systems to supply error detection capabilities is provided. The apparatus includes a memory card, parity DRAM locatable on the memory card, logic for generating and checking parity bits and logic for the control of the generating, checking and storing parity bits. Also, in another embodiment, the apparatus adds error correction code to the memory card to provide error detection and correction code to systems lacking such capabilities.

Memory card design with parity and ECC for non-parity and non-ECC systems

A self-timed circuit for use a clocked logic system is disclosed that comprises a timing detection device for detecting a timing margin of a critical path, the critical path being a path that limits the speed of the system. The circuit further comprises increase logic for increasing the speed of the system clock if the timing margin allows it, and decrease logic for decreasing the speed of the system clock if the timing margin indicates such a need. The increase and decrease logic comprise threshold generator and reset logic, and clock control logic.

Self-timed circuit having critical path timing detection

A multiple clock translator for a microprocessor is provided for synchronizing data from an external clock speed to an internal clock speed that is a non-integer multiple of the external clock speed. The translator comprises a latch circuit and a synchronization signal generator. The latch circuit receives data at the external clock speed and outputs data at the internal clock speed. The latch circuit includes an input latch and a sync latch, and receives an external clock having an enabling phase and an internal clock having an enabling phase. The input latch is docked by the enabling phase of the external clock, and the sync latch is docked by the enabling phase of the internal clock and enabled by a sync pulse. The synchronization signal generator generates a series of sync pulses that are output to the latch circuit in a selected pattern, wherein the pattern is a function of the non-integer multiple.

Non-integer multiple clock translator

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Richmond, VT, United States of America

Bruce W Singer