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When the tuner is not connected to the system, the system
controller is switched to talker after data is received from
the deck controller.
When
the system controller passes display data independ-
ently to the display controller, output of a display com-
mand when the system controller is a talker is followed by
output of the CS signal and 80-bit display data to the
display controller. After the display command
is received
the deck controller waits until transmission of the 80-bit
display data has been completed before switching to talker
status.
Display Command
(T)
System Controller
(L)
nal
80-bit display data
1
(T)
Deck Controller
(T)
Tuner Controller
Display Controller.
(L)
The
tuner
controller
also waits for transmission
of the
80-bit display data to be completed
before switching to
deck controller
command
reception
mode.
For the deck
and tuner controllers to change the display contents in the
display unit, each controller generates 80 bits of display
data
following
output
of the relevant command
during
talker status. Listener deck or tuner controller skips reading
the 80 bits of data. Following input of the 80 bits of data,
the system controller adds the necessary volume data etc,
and switches temporarily to talker status for output of 80
bits of display data to the display controller.
* Serial clock is 100kHz, the
talker being operated by internal
clock and the listener by external
EB
clock.
0 ag
(et
ra
Ae Fe, ere
eee
(H)
.
aa)
ee ee
RN
Fig. 15 System controller display data transmission timing
System Controller
(T)
el
F-sotir dispiay—4
:
[1
80-bit display
(L)
data
Command
Tuner Controller
Display Controller
(T)
me
Fig. 16 Timing for display data output from deck controller
@ Standby Function
The system controller checks whether the car's Acc key is
ON or OFF at ieast once every 6msec. (pin 50). If the key
has
been
switched
OFF
and
the
system
controller
is
switched
to talker status, a display command
is generated
and 80 bits of "all 0' data is passed to the display con-
troiler,
resulting
in the display
being cleared.
When
the
system
controller
is next switched
to talker status,
the
standby
command
is passed to the deck and tuner con-
trollers, resulting in the deck and tuner being switched off.
During
standby
mode
(Acc
OFF),
the deck
and tuner
controllers back up only the RAM data, the CPU functions
being halted. If the system controller check finds that Acc
13
is ON, the clock counter functions are continued.
If the
Acc ON condition is detected for two seconds, the system
controller transmits a display command
to the serial inter.
face together with the display data preceding the change to
Acc OFF condition, resulting in the deck and tuner con.
troller standby mode
being cancelled by that data. {f the
mode when Acc is switched OFF
is deck or tuner mode,
a tape or tuner
command
is generated
and the mode
i;
reverted to the mode when Acc was OFF.
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