December 1981, Volume 1, Number 4

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Mhz clock. The clock can be controlled from an external crystal, or from an internal oscillator, and is available to the rest of the system. Refresh is provided by the chip; software can select the interval between successive refreshes, or even suspend it entirely!

The on-chip memory management unit provides for a flexible memory structure, by allowing dynamic page relocation, as well as write protect features. The 16 address lines output by the CPU are transformed into 19 bit physical addresses. This large cache of memory will facilitate multiple users (as for example, in schools), or foreground/background processing (playing Adventure and monitoring the nuclear power plant at the same time!).

Delivery of the new CPU is not expected until the first quarter of 1983, and a price has not yet been quoted. It should be stressed that the chip will not be pin-forpin compatible with the Z80. however, it should not be impossible to make a very compact interface board, although until detailed pinouts and bus timings are published this can only be a dream. If the promise is kept of full software compatibility with the Z80, and three to five times the throughput with the same speed memory, then this will be quite some chip!

A/D BOARD FOR NASCOM £135 + VAT Fast Analogue to Digital conversion on the NASCOM * 8 Bit resolution * Sample and hold * 8 input channels * Overvoltage protection * 30 microsecond conversion * Full flag/interrupt control * Prototyping area * Built and tested EPROM PROGRAMMER £63 + VAT * Programs 2708/2716 – 3 rail * Zero insertion force socket 2508/2758 – 1 rail 2516/2716 – 1 rail 2532/2732 – 1 rail * Built and tested GRAPHICS BOARD FOR NASCOM £55 + VAT Very high resolution graphics on your NASCOM * 384 x 256 bit mapped display * Graphics software supplied * Mixed text and graphics * Full software control * 4Mhz NASCOM required * Built and tested DUNCAN LANGUAGE FOR NASCOM £12 + VAT * DUNCAN is a fast real time interpreter / control language for NASCOM and was featured in “PRACTICAL COMPUTING” May 81. _ _______ ______, MILL HILL, LONDON, ___ ___. Tel. __-___ ____

This is an OCR’d version of the scanned page and likely contains recognition errors.

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