Microprocessor applications

Microprocessor applications

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own 'watchdog' unit. This continuously monitors its operation and the program regularly checks the operation of the multiplexers and other central equipment. Any malfunction initiates both audible and visual warnings. The central equipment is supplied complete with power supply units including a 24 volt DC back-up power supply ensuring that the program will automatically restart following a ship's AC mains failure. The use of locally mounted analogue and contact multiplexer units greatly reduces the overall system cabling in the ship. Some of the optional extras available for comprehensive operating systems include exhaust gas temperature monitoring, data logging, print log, and manoeuvre recording. (GEC-

Elliott Process Automation Ltd. New Parks, Leicester, UK LE3 1UF Tel: (0533) 871331).

Microprocessor applications

More products for OEM computer

Microcomputer

Intel has brought out many new microcomputer products in 1976. Details are given here of three of the more recent devices for use with the SBC-80/10 OEM computer. This card consists of an Intel 8080A CPU, 4k bytes of ROM or PROM, l k bytes of RAM, 148 programmable parallel I/0 lines and a serial communications interface. The SBC-016 16k RAM board contains 32 Intel 2107B dynamic RAMS together with all refresh, control and interface circuitry. Up to four cards can be used with each SBC-80/10. The RAMS are automatically refreshed every 1.5 ms unless a memory or write cycle is in progress; in which case refresh is delayed until the memory reference cycle is complete.

Ampex has introduced a family of microcomputer core memories designed for terminal, peripheral and microprocessor applications. The MCM-1814, provides electrically alterable read-only memory (EAROM) and normal random access memory (RAM) in a single module. Operating in either full word or byte mode, the MCM-1814 gives 400 nanosecond access to 4096 words of up to 18 bits each. The MCM-1814 combines the proved reliability and non-volatility of core with a unique write-protect feature which prohibits alteration of data in one or more 512-word blocks. Thus, a single MCM-1814 module provides both an electrically alterable readonly memory for microprograms or other data and a normal random access memory. As the write-protect feature is controlled by switches, information can be easily changed, or new information stored in the EAROM blocks on site and the blocks again protected. The MCM-4300 memory provides non-volatile storage of 2048, 1024, 512 or 256 four bit data words. Designed specifically for Read-ModifyWrite applications, the MCM-4300 provides data access in 450 ns. A data-save feature is incorporated to prevent loss of data under all conditions of power turn on/off or temporary power failure. The Ampex MCM-1000 memory provides 450 ns access to 1024, 2048, 4096 or 8192 eight or nine bit data words and full cycle operation in 1300 ns. The MCM-1000 memory combines the core's proved reliability and nonvolatility with the enhanced performance margins and uniformity of Ampex temperature independent UNIBIT cores. The MCM family will operate at ambient temperatures up to 55°C without forced air cooling when mounted in an open card rack and up to +70°C with forced air cooling. The modules require minimal current from +5V and +10V (+12V) power supplies. Each module of all models is a completely self-contained memory including timing and control, address and data registers, decoding and drive

A wire link on the board is used to set the address of the first byte of RAM. Read/write buffers on the board provide a TTL compatible interface with the control, address and databases of the system. Read, write and refresh cycle times of the card are 735, 1360 and 735 ns respectively.

The Microprocessor Applications Bibliography covers the period January 1970 to October 1975 and contains 77 references. Each reference includes a 50 to 100 word summary of the original source and full details needed to locate it. The coverage includes journal and conference papers, books, theses, reports and patents published worldwide. This bibliography, the first in a series planned by the lEE Library, has been published in co-operation with I EE's Microprocessor Applications Group and costs £2.50. The Group provides an informal forum for the discussion of techniques associated with the use of microprocessors and of the technical aspects of microprocessor applications. It also identifies areas in which research and development are required. Although sponsored by the lEE, membership of the Group is also open to nonInstitution members. Meetings a.re held at two-month intervals and they usually take the form of short informal talks by invited speakers.

The SBC-406 board contains all the control circuitry to support an additonal 6k bytes of program memory. The sockets for this memory are included on the board. The memory array is divided into two blocks, one of 2k bytes and the other of 4k bytes, and each block can be set at any base address in the memory map, beginning on any 2k boundary. This is done using wire links and switches. The SBC-104 card can be used to increase the memory size and to enhance the I/0 capability of the SBC-80 /10. The card contains an additional 4k of RAM, provides 48 more programmable I/0 lines, adds a second serial communications interface and doubles the program memory size by providing sockets for another 4k bytes of ROM or PROM. The I/0 lines are provided by two Intel 8255 programmable peripheral interface units configured by the system software as input. Interrupt requests may originate from eight sources. (Intel Corp (UK)

(Institution of Electrical Engineers Savoy Place, London WC2R OBL, Tel." 01-240 1871. Telex 261176).

Ltd., Broadfield House, 4 Between Towns Road, Cowley, Oxford 0)(4 3NB UK Tel: 0865 771431).

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