puck@omsvax.UUCP (12/01/83)
<Ignore this line - it's meant to be eaten.> As a followup to my article on the hardware manual, I have to let this group in on another manual I've come across. It's titled "Timex/Sinclair Interfacing", by James M. Downey and Don Rindsberg. Published by Prentice-Hall, Inc., Englewood Cliffs, New Jersey 07632. What a gem. It is a book, as its name implies, about interfacing to the TS/ZX computers. The chapter headings give a pretty good indication of what the book is about: 1) Fundamentals of microcomputers 2) Construction techniques 3) Creating space for expansion in the Sinclair 4) Parallel output ports 5) Parallel input ports 6) Handling analog signals 7) Joysticks 8) Memory Expansion 9) Interfacing printers 10) The Sinclair as a dumb terminal 11) Level-shifting for the printer and the dumb terminal Schematics are given for each part of the project, and the individual parts are tied together at the end in a reasonable configuration of a dumb terminal. At each step of the way, short programs are also listed that will test out the hardware after it's hooked up. The authors specifically mention that all of the projects listed have been tested on Timex and Sinclair computers (great!). All in all, an excellent book on interfacing to the TS/ZX, and not too bad for general interfacing techniques applicable to any micro. The only thing it lacks that I really wanted was the schematic for the TS/ZX, but my other book has that, so I'm happy. Oh, yeah, it also doesn't go into major RAM expansion - the authors apparently felt that the TS/ZX RAM pack was "the most cost-effective method" of adding memory accessible to BASIC. The plans for a simple logic probe are also included in the book for debugging the hardware; most of the sections of the book assume you've built it. There are lots of little quirks and gotcha's that the book describes that would definitely cause problems in trying to roll your own interface, such as the fact that a RAM image *must* exist 32K higher than the physical RAM for the display to work. By the way, all of the convolutions of Sinclair's little box are supported in this book; that includes the 4K ZX80, even after it's been upgraded to 8K. For those who want to do your own interfacing to this computer, this book is a must. (By the way, I did get a chance to peek through the "Explorer's Guide to the ZX 81", and found it to be sadly lacking in the hardware description - I guess it's better than nothing, though.) /\ / \ <puck> \ / \/ Responses to: ogcvax \ microso \ !omsvax!puck uwvax / hplabs /
zemon@felix.UUCP (12/10/83)
The interface book you mentioned sounds pretty interesting. Does it, or have you found anything else that does, describe how to the the ZX80 as a printer buffer? Art Zemon