International Business Machines Corporation

Thomas Winlow

Michael John Palmer

Philip J Murfet

Christopher N Wallis

Adrian C Lee

Stephen Furniss

A hardware simulator comprises a plurality of interconnected programmable logic devices (20) which are connected via a data bus (22) and a control bus (24). Address signals on control bus (24) are read by an interconnect logic block (18) associated with each device to selectively link the output latches and input latches of the devices (20) to the data bus (22). Accordingly, a series of signal transfers is carried out between the devices simulating the hardware. The interconnect logic blocks may be programmed to provide whatever connections between devices are required.

Integrated circuit logic functions simulator for selectively connected

An asynchronous serial data receiver for receiving a stream of data bits, characterized by a plurality of shift registers (54) into which samples corresponding to points within said data bit stream are read, different shift registers (54) holding a different set of said samples, said points being separated by most one half of a data bit period, and a decoder (60-90) responsive to said samples held in said shift registers (54) for recognizing points of known phase within said data assessed relative to which samples which corresponding to points within said data bits may be identified for reading. The invention provides a high speed serial receiver which is particularly suitable for use within disc drives and data storage and retrieval systems in general. The serial data receiver of the present invention does not require a clock synchronized with the incoming data. Furthermore the serial data receiver is able to share the sampling of the data bit stream between a plurality of shift registers (54) none of which need be clock more than once per data bit period.

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Eastleigh, United Kingdom

Thomas Winlow