ASPECTS OF INTELLIGENT SENSOR RECONFIGURATION

One of the more powerful aspects of ASICs for intelligent sensors is t he possibility of reconfiguring the analogue subsystems under digital control. This permits a variety of self-test and auto-calibration acti vities, which give increased accuracy and enhanced reliability, despit e the greater complexity of such systems. In this study, possibilities are explored for exploiting such techniques by means of circuits fabr icated using standard cells. At present such cells do not provide a fu ll instrumentation specification, and a parallel programme is concerne d with the development of cells of higher performance. Standard cells, however, allow a comprehensive study of both hardware and software im plications of providing full self-test and auto-calibration facilities . One of the implications of providing such a wide range of reconfigur ability is that it is possible to create configurations that are not w orkable and may even be destructive. Therefore an important aspect of software drivers for such devices, and for the human interface, is the provision of software filters that prevent such forbidden configurati ons from being implemented, yet without inhibiting the versatility of the approach. The application and use of such filters, which are based on a process of bit-wise masking, are illustrated with examples.