HP 5384A Service Manual

8-37. LOGIC SYMBOLS
8-38. The electronic sy mbolog y used in thi s book is
ex
plained s tarting in paragraph s 8- 39.
8-39. EXPLANATION OF NEW LOGIC
SYMBOLS (by F. A_ Mann)*
8-40. Introduction
8-41 . The International Electrotechnical Co mmi ss ion
IIE C) has been developing a very p owe rful sy mb olic
language th at ca n show the relation s hip of each input
of a digital logic circuit to each output wi thout
show in g ex pli citly the internal logic. At the heart of
the sys tem is dependency notat io n, w hi ch will be ex-
plained in a later paragraph.
8-4
2. The sys t em was in t rodu ced in the USA in a
rudimentary fo rm in IEEE / ANSI Standard ¥32.14-1973.
La c king at that time a complete development of
depend en cy notation, it offered littl e more than a
s
ub sti tuti on of rectangular shapes for the familiar
distinctiv e shapes for representin g the basicfu ncti ons
of AND, OR, negation, etc. This is no lon ge r the case.
8-4
3. Int ernat iona lly , Workin g Group 2 of IE C T ec h-
nical Committee TC -3 is pr epar i ng a new document
( Pu blicat ion 617-12i that will consolidate the o ri ginal
wo rk s tarted in th e mid 1960 's and pu blished in 1972
i
Pu blicat ion 117- 15 ) and the ame ndm e nt s and sup -
pl ements that have foll owed. S imil arly for the USA,
IEEE Co mmitt ee SCC 11.9 is r ev i si ng th e publi ca ti on
IEEE Sta ndard 91 / ANSI Y32.14. Texas Ins trum en ts (and
He wlett -Packar d\ is partic ip a tin g in the work of both
organizations and {a l Supplement to th e (T exas I ns tru-
me nt s) TTl Data B oo k intr o du ces n ew l og ic symbols
in an ti c ip at ion of the new stand a rd s. Wh en chan ges
are made as the standards de velo p, futur e e diti o ns of
the TTL Data Book will take those changes into
account.
8-44. The fo ll ow in g exp lan atio n of th e n ew sy mbolic
language is necessarily bri ef and greatly co nd ensed
fr
om what th e standards publi cations will finally co n-
tain. This ( description ) is not in ten de d to be su ff icient
for those peop le who will be developing sy mbol s fo r
new devi ces. It is prim arily in tend ed to make po ss ibl e
the
understandi ng of the symbo ls u sed in this book;
com paring the sym bol s with f un c tion al bl ock dia-
grams and/ or fun ction tables will further help that
understanding.
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8-45. Symbol Composition
8-46. A sy mb ol comprise s an outl in e or a comb i-
nati on of o utline s together with one or more qualify-
ing symbols (characters ). The shape of the symbo ls
(
outline) is not si gn ifi c ant. As s hown in figure 8-2,
general qualif y ing symbols are u se d to te ll exactly
what logical operation is performed by the elements.
Table 8-2 show s th e general qualifying sy mbols used
in the T.l. TTL data bo ok. Inpu t lin es are placed on t he
left and output lin es are placed on th e right . When an
exception is made to that convent ion , the dire cti on of
signal flow is indicated by an arrow as sh ow n in Table
8-3.
OU TLINE\
r GENERAL QUAL IFYI NG
SYMBOL
~
__ ...
. · --
I NPUTi
20UTPUT
LINES
LINES
. .. . .
"Possible posi t io ns to r QU3 1if ying symbo ls re latin g to inputs and outputs
Figure 8-2. Te~t Setup fo r AJ C37 and C23 Se l ect io n
8-47. All outpu ts of a single, un sub divided element
always ha ve id entical internal log ic states determined
by th e f un cti on of the element except w he n ot he r-
wise indicat ed by an associated qua lify in g symbo l or
label inside the ele ment.
8-48. The o utlin es of el emen ts may be abutted (ad-
joining ) or e mb edded {e nclosed ) in which case the
fo
llowing conventions appl y. There is no l og ic con -
nec tion bet wee n th e e lem ents when the lin e commo n
to
their outlines is in the dir ec tion of signal fl ow.
Ther e is at l eas t one lo gic co nnection bet ween th e
elements when the li ne common to th e ir o utline s is
perpendicular to th e d ir ection of signal flow. The
number of lo gic con ne c ti ons between e lements will
be clarified by th e u se of qualifying symbo ls and this is
discussed f urth er u nder that topic. If no indications
are shown on either side of the commo n l ine, it is
assu med the re is only o ne connection.
8-49. When a c ir cuit has one or more in puts that are
co mmon to more than one ele m en t of the circ ui t, the
co mm o n- control blo ck may be u se d. This is the on ly
di s tincti vely shaped out l in e used in the IE C system.
*From " 1961 Supp leme nt to the TTL Data Book for De sign
Engineer~ ". copyr i gh t . r; 1 98 1 Te xa ~ Instru men ts I nco rpora te d.
Reproduced by pe rmi ~s i on.
B-5

HP 5384A Specifications

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Brand	HP
Model	5384A
Category	Cash Counter
Language	English