Sony CDP-101 - Remote Control Circuit Description

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3. CIRCUIT DESCRIPTION
@ CX7947
3-1. Summary
CX7947
is
a
power
consumption
reduction-type
remote
control
LSI,
When
no
key
input
exists,
it
can
_
be
initialized
by
stopping
the
clock.
On this model, if a function key is not pressed, it
is in the initial state and the IC pins maintain the
following states.
1) IC state for initial state
© ‘clock stopped
© key output pins (KO1 — KO8) maintain level
soy?
Pin Name
Function
VSS
KO6
KO7
KO8
IR
MDS
MD4
MD3
MD2
MD1
MDO
KI8
KI7
KI6
VDD
| GND
key output
key output
key output
remote control
output
mode switching
mode switching
mode switching
mode switching
mode switching
mode switching
key input
key input
key input
power supply
ie)
remote control output (IR) pins maintain level
“ Q”’
64?
© indication output (IND) pins maintain level
2) Release of initial state
The initial state is immediately released when
there is input to the key input pins.
3) Clock on/off
' The clock oscillation is stopped for initial state
only. When aswitch is turned on from initial state,
the clock begins oscillating within 10 msec.
Once oscillation begins, even if key input stops
right away, oscillation continues for 9.0 ms, then
jt returns to initial state and oscillation stops.
Oscillation continues while key input continues or
during remote control output.
eee
to, | | sto,
a oscillation .
}—___—
9.0
msec
———.>|
clock
4) Clock oscillation stopped state
CLI pin: maintained at VDD level inside IC
CL2 pin: level ‘1’? output
3-2. Pin Function Description
Pin Name Function
key input
key input
key input
key input
key input
indication output
oscillation input
oscillation output
key output
key output
key output
key output
key output
1
2
3
4
5
6
7
8
9
3-3. Data Code
©
Each
switch
is
connected
to
one
pin
of
the
key
matrix
output
pins
(KO1
—
KO8)
and
one
pin
of
the
key
matrix
input
pins
(KI1
—
KI8),
The
data
codes
for
each
switch
have
the
following
relation-
ships
depending
on
to.
which
pin
each
switch
is
connected,
R1Ol]—
© Data code 2° and the switches have the following
relationships. On this model, pin MDO is used
open, so the data code is “0”.
_ Switch
2 switches used, MDO is used open
3 switches used, MDO sends level ‘*‘1”
Level “1” or level ‘‘0” can be impressed continu-
ously to MDO DC-wise or during key read-in only.
In this case, if level “1” is impressed during key
read-in, remote control output data code 2° will
have “1”? output. However, if level ‘1’? is im-
pressed DC-wise, power consumption is performed
_ by the Pull Down register.