Hewlett-Packard J. Vol 33 No 8 (August 1982)

Hardware Bennett, K H and Singleton, P 'The design of a microprocessor-based access logic for the Cambridge ring' J. Microcomput. Applic. Vol 5 No 3 (1982) pp 195-207 The Cambridge Ring represents one solution to the problem of providing high bandwidth communication between nodes which are geographically close (the Ring speed is 10 Mbit/s and the distance between nodes is about 400 m). This paper considers the problems of using the full bandwidth potential when interfacing high speed devices such as computers. The authors have thus designed an access logic with the following objectives: it should be an outboard processor containing communications software; a high host-host transfer rate is essential; there should be short hosthost response times; and there should be error-detection, message ordering and a fair scheduling policy. The design they hit upon was a Z80based DMA device which used 8-bit data and 16-bit address buses. The design of the device allows the upper and lower bytes of the transmit and receive buses to be superimposed. The main use to which the device will be put it interfacing 4080s, PDP-I I s and LSI-I Is to Keele University's Ring network.

Best, D W, Kress, C E, Mykris, N M, Russell, J D and Smith, W J 'An advanced architecture CMOS/ SOS microprocessor' IEEE Micro Vol 2 No 3 (August 1982) pp 11-26 Most architectures in use today's microprocessors are yon Neumann register-oriented architectures with limited high level language support. The authors describe a 16-bit processor implemented on a single silicon-onsapphire (SOS) die and using a language-oriented stack architecture. The chip is said to execute more than 355 000 operations/s when used with a medium speed memory. Discussions of the instruction set architecture, microarchitecture, implementation, interface and performance. An appendix - a portion of the programmers reference card - provides an overview of the instruction set.

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Calaghan, V and Barker, K 'SAS - an experimental tool for dynamic program structure acquisiton and analysis' J. Microcomput. Applic. Vol 5 No 3 [1982) pp 209-223 The life cycle of a program may be envisaged as comprising two stages development and maintenance. Trle authors estimate that the maintenance part accounts for 75 per cent of the total program cost. In addition software now accounts for about 80 per cent of the total life-cycle system cost. The authors have thus designe d an experimental microprocessor-based tool, SAS (software analysis system), to enable dynamic program structure acquisition and analysis to be made on digital machines. The system uses a universal hardware extraction techniques to obtain branch vectors which are used to analyse and display the structure of the software being monitored. The authors define their maintenance activities (as described by Swanson) as corrective - fixing a preexisting error; adaptive - modifying the software to accommodate environmental change; and perfective improving or augmenting the performance capabilities. The hardware comprises CPU board, disc controller, two structure table RAM boards, EPROM and structure and control boards. The authors show an example of how the system works: the location of a hex work output routine associated with 990 microcomputer and monitor.

Di Manzo, M, Frisani, A and Vernazza, T 'A monitoring distributed system'

Microproc. Microprog. Vol 10 No 1 (August 1982) pp 1 9 - 2 4 A hardware monitor for a multimicroprocessor system is presented. It is based on a number of interface cards plugged in'to the local and global buses of the target machine. Signals are sent to a supervising CPU that performs data reduction and interpretation and controls the interface cards. Problems with the target architecture and from the nature of the signals are discussed.

Hewlett-Packard J. Vol 33 No 8 (August 1982) A special issue on silicon IC fabrication. Topics covered include optical IC litho-

graphy using trilayer resist, beam recrystallized polysilicon, dry etching, X-ray lithography, electromigration and thin films formed by plasmaenhanced chemical vapour deposition. Lin, L 'Spectrum analyser chip for speech recognition' Electron. Prod. Des. Vol 3 No 8 (August 1982) pp 51--52 A monolithic audio spectrum analyser is described. It is designed to perform the spectrum analysis function of a speech recognition and is implemented with double poly NMOS technology. Filter characteristics for 16 channels are given.

Myers, W 'Towards a local network standard' IEEE Micro Vol 2 No 3 (August 1982) pp 2 8 - 4 5 Tow special issues of Microprocessors and Microsystems have appeared this year on local area networks. The field looks set to provide the links in office and factory automation. Ware Myers sets out the history of LAN standards since the setting up of the IEEE 802 standards project in Feburary 1980 to establish new standards. Applications supported by a LAN considered by the committee included file transfer and access protocols, access to remote databases, graphics, work processing, process control and digitized voice transmission. The network must also support a range of peripherals and gateways to other networks. Alternatives such as the carrier-sense multiple access method token pass and token ring method are outlined. The article concludes with the identification of three possible scenarios for the future of LANs.

Rappaport, A 'Instruments' EDN Vol 27 No 14 [16 July 1982) pp 106-114 Computer-aided engineering (CAE) workstations are moving IC development from the draughting room to the systems design laboratory. Custom and semicustom IC technologies are particularly suited to approaches involving CAE workstations. Much of the work will be based around silicon foundries which make ICs from customer-supplied artwork. Andy

microprocessors and microsystems