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Table 8-1 . M
a
j
o
r
Sig nal Defi n itions
M
od el 5383 Α
M
ai n tenance
Mnemonic
Description
A, B ,C,D
Display Data Bu s BCD lines ( W eig h t: Α=1, Β=2, C=4, D=8) .
M
G
TT L ver sio n of
M
GE;
u
se d to co n t r ol
R
ST B L atc h .
M
G E
M ain gate control sig nal (EEC L logic level); allows i npu t to fr equ e ncy
co un ters (w he n L ow) .
MR S
Co un ter
r
eset a nd display
d
igit test command (ge n e r ate d by
R
S sig n al) .
O F
Ove rflow ; low TT L level i nd icates ove rflow of freque n cy co un ter s .
RB I
R
ip p le
B
lank in g I n pu t; low TTL level allows
b
la nk i n g of ze r os i n d is p lay;
h
igh TTL level i nh ibits zero
b
la nki n g .
RBO
Rip p le Blan k i n g O u t pu t; low TTL level w h e n zeros a r e
b
la nk ed f r om
d
isp lay ;
h
ig h TT L level at all ot h er times.
R
S
H
ig h
TT L
level
r
esets
cou nte r w he n
GAT E TIME
switc h
posi-
tio n is ch anged .
P
rovid es
d
isplay
d
igit test w h en GAT E TIME switc h is
h
el d b etween
positio ns .
_
R SC
R
SC
TTL signals t h at
r
eset f reque n cy co unte r s .
R
ST B
TT L signals th at
r
eset t h e var iable Time
B
ase co unte r
a
nd Mai n Gate
R
ST B
L atch es dur i ng t he upd ate se qu en ce (see
F
igure 4-3) .
50 ΤΗ RU S9
E
igh t co n ti n uo u sly cyclyi ng
d
is p lay scan sig n als ; eac h sca n li n e activates
one
d
isplay
d
igit.
Τ _ R
TT L signals th at tra nsfe r
f
requ ency cou nter B CD
d
ata to t h e sto rage
TR
latc h es duri n g the
u
pdate se que nce (see
F
ig ur e 4-3) .
W
U
sed fo r
o
u tpu t m ultiplexi n g of t h e
H
ex Mu ltiplexed Deca d e Co un te r
B CD c ha racter s . T hese sig n als also dr ive t he Ηυ
B
CD-to-Decimal ιοη -
Ζ
ve rte r
p
roviding th e Scan sig nals (50 thru S9) .
._1s
L
ow TTL level that ill u minate t h e LE D
d
is p lay
d
ecimal
p
oin ts an d co nt rol
1s
lea d in g ze r o blank i ng .
111s
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