Vol.2 n°11 november 1977

Vol.2 n°11 november 1977

p.3 In the Queue (table of contents)

p.3 In the Queue (table of contents)

Foreground

p.10 MEMORY MAPPED IO

p.10 MEMORY MAPPED IO

[theme : Hardware] [author : Ciarcia]

p.50 USING INTERRUPTS FOR REAL TIME CLOCKS

p.50 USING INTERRUPTS FOR REAL TIME CLOCKS

[theme : Real Time Techniques] [author : M F Smith]

p.68 DOES ANYBODY KNOW WHAT TIME IT IS?

p.68 DOES ANYBODY KNOW WHAT TIME IT IS?

[theme : Peripherals] [author : Grappel]

p.72 ADDING AN INTERRUPT DRIVEN REAL TIME CLOCK

p.72 ADDING AN INTERRUPT DRIVEN REAL TIME CLOCK

[theme : Real Time Systems] [author : Sneed]

p.76 FLOATING POINT ARITHMETIC

p.76 FLOATING POINT ARITHMETIC

[theme : Software] [author : Hashizume]

p.80 BUILDING A COMPUTER FROM SCRATCH

p.80 BUILDING A COMPUTER FROM SCRATCH

[theme : Hardware] [author : Jones]

p.94 A 6502 PERSONAL SYSTEM DESIGN : KOMPUUTAR

p.94 A 6502 PERSONAL SYSTEM DESIGN : KOMPUUTAR

[theme : Hardware] [author : Brader]

p.146 IMPLEMENTING AN LSI FREQUENCY COUNTER

p.146 IMPLEMENTING AN LSI FREQUENCY COUNTER

[theme : Hardware] [author : Lynne]

p.150 SWEET16: THE 6502 DREAM MACHINE

p.150 SWEET16: THE 6502 DREAM MACHINE

[theme : Software] [author : Wozniak]

p.166 DO YOU NEED THE REAL TIME?

p.166 DO YOU NEED THE REAL TIME?

[theme : Real Time Systems] [author : Trollope]

Background

p.18 SIMULATION OF MOTION : An Improved Lunar Lander Algorithm

p.18 SIMULATION OF MOTION : An Improved Lunar Lander Algorithm

[theme : Modelling] [author : S P Smith]

p.26 A MINICOMPUTER FAIR : TINY AND PERSONAL

p.26 A MINICOMPUTER FAIR : TINY AND PERSONAL

[theme : Computer Fairs] [author : Piele]

p.54 SPIKES : Pesky Voltage Transients and How to Minimize Their Effects

[theme : Hardware] [author : McCain]

p.172 NIMBLE : THE ULTIMATE NIM?

p.172 NIMBLE : THE ULTIMATE NIM?

[theme : Software] [author : Doliner]

Nucleus

p.4 In This BYTE

p.4 In This BYTE

p.6 The Compleat Robotics Experimenter

p.6 The Compleat Robotics Experimenter

p.30 Letters

p.30 Letters

p.37 BYTE's Bugs

p.38 BOMB Lands on APL

p.38 BOMB Lands on APL

p.46 The TRS-80 : Radio Shack's New Entry

p.46 The TRS-80 : Radio Shack's New Entry

p.60, 197, 218 Programming Quickies

p.60, 197, 218 Programming Quickies

p.66 My Experiences with the 2650

p.66 My Experiences with the 2650

p.145 Ask BYTE

p.145 Ask BYTE

p.160 Switching ROMs in the Fairchild F8 Evaluation Kit

p.160 Switching ROMs in the Fairchild F8 Evaluation Kit

p.162 BYTE's Bits

p.162 BYTE's Bits

p.170, 198 Technical Forum

p.170, 198 Technical Forum

p.190, 220 Languages Forum

p.190, 220 Languages Forum

p.206 Book Reviews

p.206 Book Reviews

p.211 Clubs and Newsletters

p.211 Clubs and Newsletters

p.226 Classified Ads

p.226 Classified Ads

p.228 What's New?

p.228 What's New?

p.256 BOMB

p.256 BOMB

p.256 Reader Service

p.256 Reader Service

Cover by Bruce Holloway

In this BYTE

In this issue, author Steve Ciarcia begins what we expect to become a regular feature in BYTE: Ciarcia's Circuit Cellar. Steve, a senior engineering consultant to the aerospace industry by profession, is a rare combination of writer and tinkerer. The conceptual model he brings to his interactive column format is that of the late C L Stong's stewardship of "The Amateur Scientist" in Scientific American, but with an emphasis on hardware and software combinations to accomplish interesting applications of personal computing systems. Steve welcomes feedback from readers ...CH

Games and models which employ moving objects require some attention to details of motion as simulated by a computer program. Beginning a series of articles on the subject of moving objects, Stephen P Smith's Simulation of Motion : An Improved Lunar Lander Algorithm shows how a real time game can incorporate models of motion in more than one dimension.

Donald T Piele shows that a computer fair doesn't have to be big to be good . A Minicomputer Fair: Tiny and Personal describes the University of Wisconsin's efforts to produce their own micro extravaganza, which drew over 700 attendees. Readers may get some ideas about putting on shows of their own based on Professor Piele's experiences.

What might not be appreciated by the neophyte is the fact that an interrupt driven clock suggests other uses besides keeping time. In M F Smith's article on Using Interrupts for Real Time Clocks you 'll find a simple timekeeping algorithm, and a sketch of how it can be extended to share processor time between two different processes.

Do you occasionally find incorrect data in your computer when you know you entered the correct information and processed it with a reliable program? Does your computer do strange things every time the washing machine or furnace turns on? Perhaps your problem is voltage transients. John McCain writes about Spikes: Pesky Voltage Transients and How to Minimize Their Effects.

If you want to post a calendar of events in your computer's memory with a resolution of 1 second, a mere three integrated circuits added to an existing LSI digital clock can turn it into a source of time information for your computer. Use Robert Grappel 's article in this issue to find an answer to the metaphorical question: "Does Anybody Know What Time It Is ?"

Any regular source of interrupts can be used as the key element in a simple real time clock for the typical personal computer. James R Sneed shows how to create such an interrupt source, then program a 6502 to generate internal variables for hours, minutes, seconds and 1/15th seconds of the day in his article on Adding an Interrupt Driven Real Time Clock.

If you do a lot of mathematical calculations on your microcomputer, you'll enjoy reading Floating Point 'Arithmetic by Burt Hashizume. Find out how to add an economical floating point package to your system and improve your number crunching facilities.

An excellent way to learn about computers is to build one yourself. Hilary D Jones shows that this is not such a terrifying task. Read Building a Computer From Scratch and find out how to construct a working (albeit limited) computer for under $70 (plus the price of a power supply).

Occasionally readers ask for detail plans of computer systems. David Brader, a BYTE reader from Electric City WA, has implemented an excellent piece of homebrew craftsmanship in his Kompuutar system based on the MOS Technology 6502 processor. In this issue, we provide David's complete design for the central processor, control panel interface, and serial terminal interface of a general purpose computer.

Frequency counters are useful tools for a variety of applications. Perry Lynne shows you how to add one to your microcomputer in Implementing an LSI Frequency Counter. His design takes advantage of the Intel 8253 programmable interval timer (as well as the power of the microprocessor) to produce a design that is both accurate and economical.

How do you make an 8 bit machine emulate a more comprehensive design? In his article, SWEET16: The 6502 Dream Machine, Stephen Wozniak details the design and functions of a low level interpreter for 16 bit operations which extend the functions of the more limited 8 bit 6502 processor.

Continuing the theme of real time and how to keep track of it, G A R Trollope provides an example of the interrupt driven approach, implemented through the IRQ interrupt line of a 6800 processor with a PIA port. Do You Need Real Time? If so, turn to th is article.

The game of NIM is well-known in the annals of computer lore, but many people have had no contact with it. Irwin Doliner presents us with a version of the game and supplies us with the design theory behind it in his article, NIMBLE: The Ultimate NIM?