Abstract: The present invention relates to an access request control apparatus and more specifically to an apparatus for determining priority between a plurality of access requests in a memory control apparatus which uses a pipeline. One of the access requests from a plurality of channel processing devices CHP's is selected by a first priority determination circuit. The selected CHP request, the requests from a plurality of central processing units and the request in the loop-back of the pipeline control circuit are considered for selection by a second priority determination circuit. In case a CHP request, selected by the first priority determination circuit, is not selected by the second priority determination circuit or selected but nullified in the course of the pipeline, the CHP request is returned to the first priority determination circuit. But, in this case, a higher priority is given to the CHP request in the first priority determination circuit.

Abstract: A memory system (30) for storing and delivering instructions to a central processing unit (14) in a data processing system includes a main memory (32), a buffer memory (35) and a control unit (42). The main memory includes a series of memory slots (34), each memory slot storing one track. Each track consists of a sequential list of instructions which are executed in order unless a jump instruction is encountered. Each track ends with a jump instruction and begins with an instruction which is a target instruction of at least one jump instruction. The control unit copies each track into the buffer memory prior to delivering instructions from that track to the CPU. This buffer has a pointer (40) which specifies the next instruction in the buffer to be examined. If the instruction is a non-jump instruction, it is delivered to the CPU.

Abstract: A programmable sequencer 10 uses an input mapping circuit 20 including a programmable logic array 30 to map decision variable input conditions onto branch address signals, which are used with primary address signals to form a next state address for state word memory 50. Input mapping circuit 20 preferably includes a branch control circuit 40, controlled by feedback signals from the output of state word memory 50, to selectively transform branch address signals to allow different states to use state word locations sharing the same primary address in state word memory 50. The preferred embodiment also includes a diagnostic circuit 80 useful for programming, and/or diagnosing operation of, sequencer 10.

Abstract: A memory accessing control for a microcomputer system is compatible with both static and dynamic type memories. A gating circuit is responsive to read/write and address latch enable control signals of a microprocessor, and provides an enable signal utilized to generate a chip enable signal compatible with the timing and control requirements of both dynamic and static memories.

Abstract: An interprocessor communication system for a multiprocessor data processing system includes a common control circuit which includes a plurality of clusters where each cluster includes a plurality of semaphore registers and a plurality of information registers. Each type of register may be directly addressed by any processor. Each processor has a cluster code indicative of which, if any, of the clusters the processor may access. Each processor has a local control circuit in relatively close physical proximity and each local control circuit can communicate with the other local control circuits to determine whether one of its counterparts is requesting an operation. The local control circuit monitors and controls the issuance of the processor's instructions to the common control circuit. The local control circuit includes a plurality of local semaphore registers maintained with a copy of data in the common semaphore register cluster associated with that processor.

Abstract: A single-chip microcomputer comprises at least two separate and independent electrically erasable programmable read only memories (EEPROMs) on-board which may be independently programmed, erased and read. Each part of the split EEPROM has its own data bus and address bus. Programming and erasing is controlled by a program register which has separate bits for configuring and latching the data and address buses of a selected EEPROM array, for providing programming voltage to the array of choice and for choosing between programming and erasing the selected array. The split EEPROM provides versatility to the user in allowing one part of the EEPROM to be programmed while the program stored in another part of the EEPROM or RAM may be read and utilized. In addition, test time and effort of the microcomputer may be considerably reduced.

Abstract: A scan apparatus provides an interface and control signals between a secondary computer and data locations in a host computer. The scan apparatus functions independently of the normal operation of the host computer. Scan-out is performed transparently to the operation of the host computer. The host computer is constructed using circuits on semiconductor chips. The semiconductor chips are organized in blocks. Chips within each block include scan apparatus which controls the scan operations in connection with that chip. The scan apparatus in each chip is connected through two I/O pins to a clock line and to a bidirectional scan data line. The scan apparatus on each chip includes a multimode sequencer so that each chip in each block can be independently performing scan sequences. The block scan apparatus and the secondary computer perform the functions of requesting a scan sequence for transmitting the scan data.

Abstract: In a sequence controller, a sequence program store device includes an instruction store unit for writing a specific instruction dedicated to the sequential control and a plurality of latch circuits respectively associated with the outputs from an output unit. The latch circuits are controlled by a signal from a processing device which periodically calls and processes the program from the store device and executes a specific output processing when external input signals satisfy a logical state set by the program; the latch circuits, if a transition condition of the program is satisfied when the specific instruction is processed, retain an output state of the output unit until the next transition condition is satisfied, and release the state retaining the output state before the next transition condition is satisfied.

Abstract: A buffer storage control system is incorporated in a multiprocessor and includes therein operand side buffer storages and instruction fetch side buffer storages. Under control of the system, a store operation is achieved with the use of an identification flag, which indicates that the related address invalidation is to be effected at the operand side or the instruction fetch side, while a fetch operation is achieved with the use of the identification flag which indicates that the related store address is to be recorded in the operand side buffer memory (TAG) or the instruction fetch side buffer memory (TAG).

Abstract: An automatic numbering apparatus for use with a text processing system has first storage element for storing a starting position specified on a display screen of a display and the kind or type of a corresponding outline number, an outline number generator for sequentially generating, when the starting position of the specified item is specified on the display screen and a predetermined key is operated, outline numbers corresponding to the starting positions of the specified items, second storage element for storing the outline number generated by the outline number generator, the starting position thereof, and a corresponding page and text inputted by a data input device (keyboard), and an outline searching device for searching for the outline number, the corresponding position and the corresponding page of the stored contents in the second storage means, whereby the text containing the items can be printed out and a table of contents comprising a list of the items and the corresponding pages as searched by t

Abstract: A sequence control system employing a plurality of programmable logic controllers, each having the same construction and being linkedly connected, can perform complicated sequence control resulting from executing an overall user program based on that of each programmable logic controller while exchanging necessary input/output data; each of the programmable logic controllers can also perform sequence control by itself.

Abstract: To prevent change of data in a non-volatile programmable, ready-only memory (25) forming, together with a microprocessor (23) a control unit, for example for an automotive vehicle, while permitting programming of the memory from an external programming unit (P, 1), an interface (3, 11, 12) is provided through which a release-enable bus (13) also passes, data being transmitted in accordance with a predetermined characteristic--even or odd parity--, the parity correctness being checked. If the parity is correct, an "enter" signal is provided on the release-enable bus for storing the data; if not, retransmission is attempted for a predetermined number of time, and if it cannot be correctly effected, a malfunction indication output signal is generated.

Abstract: A peripheral controller (data link processor) controls data transfers between a host computer and a plurality of tape peripheral units and a single printer peripheral unit. A master microprocessor commands three subordinate controllers to permit concurrent data transfers through a buffer memory in both the Read and the Write directions. A dual channel control from the master microprocessor actuates a DMA switch so that data transfers to/from the tape units can be controlled by switching on alternate control lines which regulate the data transfer operations.

Abstract: An I/O controller functions to provide management of, control of, while functioning as two "virtual" data link processors for at least two separate types of peripheral terminal units, thus enabling data transfers between a host computer and any selected one of the peripheral terminal units. A commonly shared logic interface, common to both virtual controllers, is selected for use by a Request-Program Array Logic unit which arbitrates the utilization of the common logic by one of two virtual controllers at any given time. A first and second status latch is provided in the common front end interface of the I/O controller whereby each status latch provides status signals to the main host computer system of the state of any one of two virtual controllers which share common interface to a host computer.

Abstract: A data communication computer network system is arranged to interconnect autonomous computers with a shared single communication channel to provide point-to-point communication between a plurality of computers. Each computer is connected to a channel control means coupled to the shared channel for establishing and removing the point-to-point communication line. Once a point-to-point communication line is established between a source computer and a designated destination computer, all the information, in the form of data packets, to be transmitted therebetween is transmitted without interruption, by means of successive transmission of the data packets.

Abstract: Plural stations are connected to two independent serial buses and they are permitted to occupy a first serial bus in a predetermined order under control of a bus controller. A second serial bus is used for transmitting to the bus controller an urgent bus occupancy request issued by any of the stations. Upon receipt of the urgent bus occupancy request, the bus controller permits the request-issuing station to occupy the first serial bus regardless of the predetermined order, thereby insuring a fault-free operation of the system for transmitting data between the stations.

Abstract: A data transfer network includes a group of disk drive peripheral units, each has dual ports for connection to two separate peripheral-controllers. A host computer can initiate either peripheral-controller to access selected disk drive units for Read/Write operations.

Abstract: A selective, non-manual power controller provides the selective, non-manual power control of various components of a data processing equipment from and reports the power status of such components to a central location. As opposed to pass power controllers which were limited to powering on or off all of the computer equipment controlled by a given controlling element, this invention provides a non-manual capability for remotely powering on or off any one or more components of a system or systems in a selective manner and providing the power status thereof. By being able to selectively activate or deactivate any or all of the components of a data processing system, the ability to conserve electrical energy is optimized. In many cases, a single component or a set of components are not used for extended periods of time, such as an entire production period or at least a large portion of a production period.

Abstract: A silicon semiconductor wafer containing a plurality of silicon integrated circuits formed therein or attached thereto contains at least one data bus to which some of the circuits are connected. Each of the circuits coupled to the data bus contains an arbitration request circuit which selectively passes a signal that requests that its circuit be given access to the data bus so it can transmit information to another circuit on the wafer. In addition, each of the circuits coupled to the data bus has an arbitration circuit which detects which of any of the circuits coupled to the data bus is requesting access to the data bus and facilitates its circuit gaining access to the data bus if its circuit has a higher preselected priority than any other circuit which is simultaneously seeking access to the data bus. The distribution of the arbitration request circuits and of the arbitration circuits simplifies layout and tends to improve the speed of operation.

Abstract: A data transfer controller allows data to be transferred from a network bus to a system bus in a host computer. The controller has a network bus interface for communicating with the network bus and a system bus interface for communicating with the system bus. The system bus interface has first and second buffers. A dual port memory is utilized and has one port operatively connected to one of the buffers in the system bus interface and to a microprocessor. The direct access channel is established and operatively connected to the other buffer of the system bus interface as well as coupled to the microprocessor and associated control logic. A switch under control of the control logic establishes connections between the second port of the dual port memory and either the direct access channel or the network bus interface.