May June 1980 - Commodore Computers

MAY/JUNE. WAY/JUNE. 1980. I960. ISSUE 4. 4 COMPUTE. 37
Review:
PET AND THE IEEE 488 Bus (GPIB),
by Eugene Fisher and C. W. Jensen.
Osborne/McGraw Hill, 233 pp. $15.00
$15.OO
Review by
Review by
Jim Butterfield
The IEEE-488 bus may be a small part of the overall
PET/CBM system, but there's enough in it to fill a
book - and then some. One gels gets the impression
ion
that Fisher and Jensen could have gone on for
another 200 pages or so without exhausting the subject.
It's a very thorough book, and it documents
the IEEE-f88 IEEE-488 bus and PET's role in considerable
detail: line by line, command by command. The book
is primarily y aimed at hardware enthusiasts and engineering
types; but even the casual user r who just plugs
in and hopes it works will find useful information
here. There are general descriptions of what goes on,
with liberal sketches depicting the interactionn in a
somewhat whimsical form. There are extensive lists of
compatible equipment and descriptions of applications.
There'ss even a short diagnostic test which may
help pinpoint t trouble on the e bus.
For those who need to plunge into technical
detail, it's all there: from connector pin designations
to lO signal sequences, everything is spelled ed out in
detail. Chapter 5, "Execution and Timing Sequences",
is the longest chapter in the book. It contains
step-by-step outlines of everything that happens
on the bus for every relevant evant PET Basic command.
There arc are a few things the authors didn't tackle.
Chapter 6 deals with interfacingg non-standard devices.
The interface described is for a receive-only device
which responds to everything the PET sends. A
schematicc is given, , and a subsequent chapter details
a similar interface to the Centronics PI printer.
But the design of a selecting interface, which can be
called in as needed by the PET, is not touched
upon. Even a brief outline here would have been
useful.
Similarly, il the authors stay away from the question
of multiple PETs communicatingg with each other or
with a common device over the CPIB GPIB bus. It's ' s a
tricky subject and laced with pitfalls; users lI would
have been grateful for r any hints they might have
been given.
Even so, the e book has a wealth of detail on
all levels. There's hardly a page without a diagram,
chart, , illustrationn or photograph. . Timing questions
and logic sequences are described meticulously.
The book is remarkably fl·ee free from errors. A few
creep in: table 5-122 seems to have omitted the
""unlisten" " signal; page 72 should show an EOI on
the last E of GENE; page 109 seems to show the
CRR and EOI coming from the PET rather than the
external device. The sequence given on page 83:
OPEN 5,5 "TEST"" doesn't seem to work on myy
PET: it gives a syntax error. The authors might
have mentioned the one-character delay that PET
introduces in the output (so that it can append the
EOI signal at the right time).
I would have liked to see more attention given
to multiple devices. At first glance, it appears that
since PET only works one device at a time, the
single-talker, single-listener listener description is adequate.
But all devices arc are on-line during the selection sequences;
and it seems to be important t to emphasize
that any device can pull a line to true aand all
devices must release ease the line to false. That's the
whole point behind the three-wire handshake; yet I
couldn'tt find the information in the introductory
section. .
But what the book is missingm is minor compared
to what it's gOl. got. It's a gold mine of both con-
ceptual information and hard facts. It covers hardware,
software, mechanical assemblies, and standards.
It lists numerous us devices and gives copious references.
In short, it's virtually everything you wanted to
know about the IEEE-488 l bus .. or are likely to want
lO to knO\·v know in thee future.
©
Money Back Guaranlee
~.-
Dealer Inqulrt •• Welcome
UNDERSTANDING YOUR PET/CBM
Volume I: Basic Programming
New 248-page book Includes all the former TIS workbooks
except "PET Graphics." Provides Information for both ROMs and
a comprehensive Index. Only $14.95.
Also Irom from TIS
W8-3 WB-3 PET Graphics $4.95
Software produclS products 00 on cassette Of or Uoppy floppy disk with wilh complete instruction
manual. Each S24.95 S2-S.95 (cassette). $29.95 (diskette).
SW-l SW-1 MAIL B mailing list system
SW-2 CHECKBOOK record
SW-3 ACCOUNTS keep track 01 of who owes you how much
SW-4 MEOI MEDITT create and maintain date Iiles
files
SW-5 CALENDAR appOintments. appointments, meetings at·a-glance
at-a-glance
TtS TIS
P.O. Box 921, Dept. C
Los Alamos, Alamos. NM 87544
Add S2 $2 (S5