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22
All
and more
about Sharp
PC-1500
at
http://www.PC-1500.info
2-3-5. BF flipflop
'Ille CPU has two
supplies
of
power:
VCC
a
nd
VGG
.
As
the IJF llipO
op
is
driven
by
VGG
.
the
srnte of
the
BF
Oipnop
is
retained
as
long
as
VGG is in
supply.
even
if
VCC
s111
>
ply is
out.
The
BF
ni1
>llop
is
set when the
(!
Fl
input is tu
rned
from
low
10
high
level
and
reset
\vhcn
the
OFJ
;
ins1
ructi()n
is
issued
fro1
11
the
("l'lJ.
Low state
of
signal
is
on
the
fl
F
Jlipnor
output IJFO
when the
llipnop
is
active
'"
"'
high
state of
sig
nal
\vhcn
in~tc1
ive.
r---
--
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------
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---
,
'.'(;G
I
'
I
t
I
l
I
I
I
Bi:
flpfl:>p
f
I
.--:
SS
Q
I
I
CPU
L
OCIC
I
I
I
t
orr
I
P.
()
I
fif
O
I
l
I
~
I
I
'
I
CNO
L---
--
-----
-
-
-
----
- -
-
-
-
-
-
-
___
___ .J
)
!3FI
It
is
possible to
conlprise
a
n1e1nory
hackup
systcn1
using this
J~
F
fl iptl
()p.
Do not sale
this PDF!!!
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