Micro Configured For Direct DRAM Support

Published in Computer Design November, 1984

This article describes an application that I developed to demonstrate that my Z8 emulator supported even the most complex of the microcontroller's operating modes. In this application, the program constantly changes the configuration of the ports, switching between latched and unlatched and between static input and output modes. No other in- circuit emulator has ever been able to support this kind of activity.

I don't like the way the magazine edited this article. For one thing, I would never use the word “shrewd” to describe my work. The cleverness of my work should be evident from its description without my having to belabor the point. Also, the editor seems to misunderstand that this design results from my using the Z8's native capabilities in ways clearly unanticipated by its creators rather than from the Z8 having been “designed to shrink component count by generating most of the unique control signals needed in a particular application”. There is no way that Zilog ever expected the multiplexed data/address port to be used for multiplexed address/address with a static I/O port providing the data interface. This was so original that it would seem bizarre were it not so effective.