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a combination of the two. Some applications of gate-array based products are in the automotive market, controlling engine timing, fuel flow emissions ...

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a combination of the two. Some applications of gate-array based products are in the automotive market, controlling engine timing, fuel flow emissions and so on, security systems and pinball machines. The author of the second article enumerates the factors that must be taken into account to determine the feasibility of various array technologies and supplies comprehensive array- and vendor-selection questionnaires. Gate-type limitations, packaging, and delivery time depend upon the array chosen and the quality of service offered by the vendor.

Kruger, R 'Intelligent GPIB controller' Electronics Industry Vol 7 No 11 (November 1981 ) pp 4 6 - 4 7 National Semiconductors' response to the increasingly popular demand for GPIB instruments has been the introduction of a new single-board microcomputer, the BLC-8488. The BLC-8488 facilitates communication between Multibus-compatible systems and instruments using the GPIB format. The board features I/O control blocks and can operate as bus slave or bus master on Multibus. Onboard intelligence takes the shape of a Z80A and associated circuitry including a clock generator, failsafe timer, wait control logic, I/O decoder and a programmable interrupt controller for fast processing of up to eight vectored interrupts. The board can rapidly access 1 Mbyte of Multibus memory to GPIB and five groups of GPIB commands are available to the user.

Nicholson, B 'Speech ICs widen voice-response computer system applications' Electronics Industry Vol 7 No 11 (November 1981) pp 14-17 The widespread use of voice response in computer systems has been prevented on grounds of cost. By developing cassette-player technology, Medway Data Ltd hope to lop 90 per cent off the starting price of a system down to around £5000. The Medway tape accessing system has a very fast and sophisticated drive consisting of two motors capable of driving tape at


80 in/s in either direction. Although fast (2 -3 s delay on average), this tape system cannot cope with strings of previously undefined letters or numbers such as an authorization code. This has led Medway to investigate speech ICs with Triangle Digital Services. They have worked on the Nat Semi Digitalker board and their own Instant Speech board (see Microprocessors c~ Microsystems December

1 981 ). The three different options using telephones and terminals should cater for most markets.

Nicholson, B 'Microprocessor evolution continues advances span 4- to 32-bit levels' Electronics Industry Vol 7 No 10 (October 1981) pp 21- 31 The breathless advance of microprocessor development shows no sign of slowing down and this article summarises some of the latest innovations such as dual CPUs, user instruction set definition at the bottom end, internal 16-bit operation on midrange multichip microprocessors, coprocessor strategies and sophisticated memory management support for the 16-bit market and the new 32-bit microprocessor. Dual CPU 4-bit devices can handle tasks in parallel rather than in serial and the second CPU can also implement dedicated functions such as UARTs or other I/O tasks. This approach provides an alternative to the orthodox method of adding extra memory and functional blocks to overcome the control limitations at the expense of a little extra silicon. Another approach to microchip development is to add functions so that a subset of a chip's capabilities will meet any simple control task. This is the case in the forthcoming NEC 8-bit 64-pin nMOS device. The strip-chip architecture topology (SCAT) developed by Texas Instruments allows die-size and hence price to be reduced and has great potential for modification to fit the needs of industrial, telecommunications and automotive market sectors. The fabrication of CMOS microprocessors has an even rosier future. They are second-sourced widely by the big American and Japanese companies and Intel have lost their lead in this

field to Japanese companies like NEC with their CMOS 8048s and 8049s and Hitachi's new 8-bit CMOS, the HD 6301 which contains 4 kbyte of: ROM and 128 kbyte of RAM supplemented with 29 I/O ports, a 16-bit timer an instruction cycle time of 1 #s and other features. Improvements in the Z80 have consolidated its position around the top of the multichip 8-bit microprocessor market. The adoption of 16-bit architecture for 8-bit nMOS devices as practiced by Intel allows cheap and easily understandable 8-bit upgrades. Inte[ have managed to hang on in the 16-bit scene with their independent and coprocessor multiprocessor structures though the benchmark tests used to sell all 16-bit microprocessors are 'notoriously unfair'. The article concludes with an assessment of future strategies for 32-bit microprocessors, 16-bits in CMOS, signal processing and bit-slice architecture.

Masuda, Y 'Logical analyzer aids efficiency of

digital devices'/. Electron. Eng. Vol 18 No 178 (October 1981) pp 4 6 - 4 9

Fukaya, H 'Principle and applications of logic analyzers' ]. Electron. Eng. Vol 18 No 178 (October 1981) pp 51- 54 As analogue devices increasingly become superseded by their digital counterparts, problems specific to digital equipment become apparent. One of the particular issues associated with digital systems is that of shortening the time needed for debugging because of the difficulties analysing the interaction between hardware and software in real time. The twatsu Electric SL-4601 logic analyser solves these problems and Masuda discusses the functions and characteristics and basic configuration of the analyser. Fukaya expounds the virtues of a rival piece of equipment, the Matsushita VP-366A, and insists that as well as obtaining information about digital equipment, a logic ana!yser must accumulate and display information from many channels simultaneously, issue trigger signals with a desirable word pattern and handle and display data according to the same system as is used by the equipment.

microprocessors and microsystems