Choice and use of microprocessors in health care

29 November 19 79, Middlesex Hospital Medical School, London, UK

This was a meeting at which two philosophies about the choice of microprocessors seemed to prevail. The first, and possibly the cheapest, was to purchase an 'off the shelf' machine, such as the PET or TP~S-80, and apply it to the task in hand. This procedure was not always painless, and often, as several of the presenters found out, such machines required considerable interfacing to their par- ticular problem. The alternative philo- sophy was to use a development system to produce dedicated micro- processors with the desired programs in EPROM. The latter seemed, from the afternoon session, to be having most success in the applications field.

One question asked at the meeting was: 'Should the hospital staff be trained to be computer operators?' Ideally a microprocessor system should be simple to operate; a few buttons may do the job rather than a whole keyboard, and so allow untrained staff to operate the system easily.

In the field of information storage and retreival, applications ranged from caculating and storing the results from fluid and solute balance measurements on patients in an intensive care unit, to a machine producing labels in a pharmacy.

Interesting applications in the area of physiological measurement were reported. Monitoring of physiological data in the operating theature is an obvious choice of application. Infor- mation on inspired oxygen, blood pressure, heart rate etc. is processed

to give permanent records, a visual display in the form of bar graphs and a short term trend, as well as operation of a comprehensive alarm system.

A microprocessor-controlled electro- oculography system, used to measure retinal function, was reported. Use of the microprocessor allowed a reduc- tion in the amount of external elec- tronics, and the introduction of any changes to the running of the test could be performed by simple software modification.

Although the meeting outlined many useful applications, it also demonstrated the large number of problems to be overcome before microprocessors are totally at home in the hospital environ- ment. Perhaps now is the time for the Hospital Physicists' Association Io begin microprocessor workshops to allow a free exchange of problems and ideas.

Derek Pearson, Dept. of Medical Physics, University of Leeds

Second international conference on automotive electronics

29 October - 2 November 19 79, Institution of Electrica/Engineers, London, UK, Organized by the Computing & Control and Electronics Divisions of the lEE

Oil producers demand more for their oil; governments demand greater con- trol of noise, exhaust emissions and fuel economy ; consumers demand greater reliability and more con- venience features in their automobiles. These have, in the past few years, meant that microprocessors are playing an ever-increasing part in automotive electronic systems. At this week-long conference many of the papers con- sidered aspects of microprocessor use in cars and one whole afternoon was devoted exclusively to microprocessors and microcomputers for engine controls and other vehicle electronic systems. These two sessions are reported here.

In his keynote speech, C R Barrett of Intel considered the requirements

for LSI in vehicle electronics: func- tional capacity, cost and reliability. The first two of these will not be problems, but reliability will be an issue because of the harsh operating environments found in automobiles. The current main uses of LSl are in data processing, where environments are benign and well controlled and the important failure mechanisms are intrinsic to the chips. Most research is thus aimed at these intrinsic failures, which as Dr Barrett said: 'may be the wrong thing as far as you [the auto- motive industry I are concerned.'

Many of the environmental failure mechanisms are diff icult to predict, especially from short term tests, and even much milder environments than those likely to be encountered on the road can lead to extrinsic failures. As an example Dr Barrett mentioned that a deionized water spray for less than 30 s can result in failure through the formation of tin dendrites giving shorting of leads.

The solution seems to lie in an approach similar to that adopted for military and space applications a full definition of the environment, a common specification for components, adjustment of manufacturing processes and screening to meet this specification and minimization of environmental effects through system design. The impact of harsh environments can be reduced by building in error correction and redundancy, and accepting that failures will occur.

The next speaker, D R Carley of RCA, also dealt with the environ- mental problems encountered and how they might best be overcome. RCA's approach is to use CMOS rather than NMOS, the noise immunity and out- put voltage range making CMOS more suitable. Mr Carleyalso spent some time describing the automated layout procedure developed by RCA for designing custom I/O chips. This pro~ cedure (APAR) uses a library of 60 verified cells and results in faster design but larger chips.

Papers from A Manku and D G Smedley dealt with particular appli- cations. Mr Manku described a fuel

64 microprocessors and microsLvstems