Sony ICF-7600DA - Page 8

NAMING
DESCRIPTION
(cont'd)
input
signals:
data
signal
from
the
rotary
encoder
and
request
signal
from
the
rotary
encoder
output
signal:
reset
signal
from
the
rotary
encoder
A
partial
circuit
of
the
rotary
encoder
and
these
corresponding
waveforms
at
each
input
or
output
terminal
are
those
shown
below.
_|
4-bit exclusive output ports.
34 PB3 PORT B
THRU THRU
37 PBO
(34)
(LAT-B)
(LATCH
SIGNAL)
(BAND
INFO.)
(35)
(LAT-A)
(LATCH
SIGNAL)
(FREQ.
POSITION
DISPLAY)
(36) (DAT-S) (DATA
SIGNAL)
(37) (CLK-S) (CLOCK
SIGNAL)
For
ports
PBO
and
PB1,
the
sink
current
is
minimized
to
a
specially-low
drain,
so
the
PBO
and
PB]
are
able
to
be
used
as
the
return-signal
sources
for
the
key
matrix.
Accordingly,
any
of
the
reverse-current-preventive
diodes
-can
be
eliminated
when
these
PBO
and
PB1
ports
are
used
as
the
key-return-signal
sources.
When
these
ports
are
used
as
ordinal
output
ports,
it
will
happen
any
of
the
low-level
output
signal
will
not
be
output
properly
depend-
ing
upon
the
circuit
employed,
because
of
the
low
sink
current.
In
these
cases,
pull-down
resistors
are
used
in
these
output
lines.
Under
the
port-operation
commands
like
“IN”,
“OUT”,
“SOB”,
“RPB”
commands,
etc.,
the
PAO
port
coincides
with
the
least
significant
bit
of
the
registor
or
the
operand,
the
PA3
coincides
with
the
most-significant
bit
of
them.
The
same
applies
to
the
Port
B
and
Port
C
respectively.
These
exclusive
output
ports
should
be
initialized
using
the
programmes,
because
these
ports
output
unstable
and
undefined
output
signals
at
the
initial
power-on
condition,
i.e.,
from
“‘L”
to
“H”.
The
output-data
contents
are
the
same
as
these
previous
last
ones
when
the
CE
terminal
changes
from
“‘L”
to
“H”
or
from
“‘H”
to
“L”,
and
when
the
CKSTP
commands
are
under
execution.
Accordingly,
the
initialization
with
programmes
is
needed
too
where
required.
In
this
set,
these
ports
are
used
as
those
shown
in
the
parenthesises.
The
40-bit
frequency-position
displaying
information
and
the
8-bit
band
information
are
sent
out
to
external
circuits
as
serial
data
flows.
The
data
and
the
clock
signals
are
used
in
common
for
the
band
information
(for
IC201)
and
for
the
frequency-position
information.
A partial block diagram is shown blow.
BAND-OUTPUT CODE
—_—_—___
LSB=>MSB
BUZZER
SWL_
SWH
ALARM
DATA
| BAND INFORMATION
CLOCK LATCH
METER-BAND FREQUENCY SCALE
INDICATOR
FREQUENCY-POSITION
DISPLAYS
DISPLAY
DATA FREQUENCY-POSITION
DISPLAYS
CLOCK LATCH
CLOCK LATCH
FREQUENCY
POSITION
trailing
edge
low
level
DISPLAY
BAND
INFORMATION
leading
edge
leading
edge
|
Note:
Frequency-position
display
turns
on
when
the
data
is
“1”.