Xerox Corporation

Other

Kenneth Gillett

Frank M Nelson

John W Daughton

Edward L Steiner

Stephen P Wilczek

Charles P Holt

Kenton W Fiske

Thomas Criswell

George E Mager

William P Kukucka

Andrew T Ling

Richard M Malinich

Philip Richardson

Warren L Hall

Kenneth A Davis

James J Donohue

A data communication system having a master unit, an interface, and one or more remote units. The master unit includes a programmable controller having a data processor, memory storage for storing programs and command and data bytes, and address and data buses. The interface is connected to the master unit via the address and data buses, and includes a memory connected to the data bus for temporarily storing command and output data bytes from the master unit pending transmittal thereof to the remote units and for storing input data bytes from the remote units pending transfer thereof to the master unit. A first communication path, along which command and data bytes from the interface memory are transmitted to the remote units, couples the interface with the remote units. A second communication path, along which input data bytes from the remote units to the interface memory are transmitted, couples the remote units with the interface.

Serial data communication system having simplex/duplex interface

A data communications system having a programmable master controller including memory means and command byte generating means and a plurality of additional controllers providing input data bytes to the master controller and having means for receiving command bytes from the master controller. The additional controllers are each connected to the master controller such that corresponding data bits are ORed together and means are provided for the simultaneous transmission of data bytes from the additional controllers to the master controller such that corresponding bits of the simultaneously transmitted bytes have mutually exclusive data therein.

Programmable master controller communicating with plural controllers

An electrophotographic reproduction machine for use as a copier/duplicator having a master microprogrammed controller and a plurality of area controllers cooperatively operative to carry out a plurality of machine operation tasks. At least one of the area controllers contains a separate microprogrammed controller for controlling selected tasks and devices in the reproduction machine in synchronism with the operation of other tasks as controlled by the master controller. An optical communication link couples the master and area controllers and serves to isolate the master controller from transients and a direct I/O connection.

Distributed microprocessor control system for a copier/duplicator

A data communications system for an electrophotographic type reproduction machine or copier. The system includes a programmable master controller with memory and a command byte generator. A plurality of secondary controllers provide input data bytes reflecting the machine status to the master controller and receive command bytes from the master controller for operating the machine components. The secondary controllers are each connected to the master controller such that corresponding data bits of the secondary controller are ORed together to provide simultaneous transmission of input data bytes from the secondary controllers to the master controller while assuring that corresponding bits of the simultaneously transmitted bytes have mutually exclusive data therein.

Data communications system for a reproduction machine having a master

A data communication system for an electrophotographic type reproduction machine or copier having a master unit, an interface, and one or more remote units. The master unit includes a programmable controller having a data processor, memory storage for storing programs and command and data bytes, and address and data buses. The interface is connected to the master unit via the address and data buses, and includes a memory connected to the data bus for temporarily storing command and output data bytes from the master unit pending transmittal thereof to the remote units and for storing input data bytes from the remote units pending transfer thereof to the master unit. A first communication path, along which command and data bytes from the interface memory are transmitted to the remote units, couples the interface with the remote units. A second communication path, along which input data bytes from the remote units to the interface memory are transmitted, couples the remote units with the interface.

Serial data communication system for a reproduction machine

In a controller for a host machine such as an electrostatographic copier having a central processing unit module connected via a system bus to an input-output processing unit module, a direct memory access system functioning as part of the input-output processing unit module and operative to provide a high-speed means of refreshing and updating control registers in the host machine by direct accessing of memory in the central processing unit module. The direct memory access system may be programmed to synchronously refresh-update the host machine's control registers as in its normal mode and also asynchronously refresh-update the control registers as in the abnormal mode of a detected electrical disturbance in the electro-sensitive periphery surrounding the control registers, thus requiring restoring thereof. High-speed movement of data by the direct memory access system is achieved through dedicating a portion of random access memory in the central processing unit module for such accessing, and transferring control of the system bus from the central processing unit module to the direct memory access system. This enables data accessed through a fixed sequence of addresses from dedicated memory to be transferred directly to the host machine's control registers without incurring time constants that would otherwise be had if the data were to be manipulated by a central processor in the central processing unit module.

Direct memory access module for a controller

A non-volatile storage module as utilized in a controller for directing a plurality of control registers of a host machine. The controller includes a central processor that is communicatively coupled through a system bus having control data, and address lines to the module and host machine. The non-volatile storage module includes a data memory operative to interface with the system bus for storing data, and for input-output of the data therefrom through the system bus upon command of the central processor. In addition, the module further includes a power storage unit coupled to the data memory for distributing a plurality of power signals from the host machine through a plurality of critical and non-critical power lines to the data memory for providing a power source that may be utilized therein for a power down condition and for sensing a power down condition on the critical power line from the power storage unit for the switching thereof to the data memory. The module also includes an apparatus that is operative upon indication of a power down condition from the host machine for generating an enabling signal to the data memory while a current address signal on the system bus is being received by the data memory.

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Redondo Beach, CA, United States of America

Kenneth Gillett