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and more about Sharp
PC-1500
at http://www.PC-1500.info
CD
DOB register
The
register
used IO
determine the direction
of
the
port
PB.
Selection
of
the
inpm/
outplll
port
is the same as
in
the
DDA resister.
DDB
can
read/
write data
when
the register
is
selected
(
I
101).
©
OPA
register
OPA
7
6
5
•
3
~
0
,_,__LI_!
I
I
The
OPA
register is
the
buffer for input and
output
of
di1rn
to
the
port
PA.
Jn
the
case
of
output.
DD
Ai
must
be
set
to
..
I"
(output mode) and
the register
must
be
selected
(
1110),
then
the
data
on
the
bus line
is
loaded
intoOPr'\i, Hl be
output
on
P/1i.
Jn
the
case of
input.
DD
Ai m
ust
be
set to
"O"(input mode) which prohibits
output
from
OPAi.
then
the
contents
of
PAi
arc loaded
into
OPAi
and
the
data
is
sent on
the
bus
line.
<D
OPB
register
The
OPB
register
is
the
buffer
fo
r
input and
o
utput of
data
to
the
port PB.
It
has
the
same
fu nction as the
OPA
1 ·egister.
OPB can
read/
write
data
when
the
register
is
selected
(I
I
I
I).
©
OPC
register
The
OPC
register can
read
/
write
data
when
the
register
is selected (
IOOO).
Also. the
contents
of the
data
bus
can
be
latched to
the OPC
regi~tcr
at
the
falling
edge
of
the
external input
clock P4>.
@
F
register
The
F register can
read/
write
data
when the register
is
selected
(OJ
I
I).
F0-2
determines
the clock rate of the modulation
clock
F
X
and
F3-5
the
modulation
clock of
FY.
x
_L
F6J roJ F4_1 F3J
F2J
n
J
Fo_I
I
Determines
the modulation clock
tate
of
FX
,
Determines the
modulation clock
rate
of
FY.
I
C
lock rate
0
0
0
1'
+
64
0
0
1
4>+
128
Change of
SOO
output
moae
~'
t
0
,p
+256
0
Notmal
serial
data
transfer
0
1
1
,p
+
512
I
f\1odulated
serial
data transfer
1
0
0
ol
+ 1024
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not
sale
this PDF!!!
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