Specifications

Circuit Descriptions, List of Abbreviations, and IC Data Sheets
EN 50 L03.2U AA9.
9.8 Control
The microprocessor part of the UOC has the complete control
and CC/Teletext processing on board. The User menu's and
Service Default / Alignment Mode's are generated by the uP.
Communication to other ICs is done via the I2C-bus.
9.8.1 I2C-Bus
The main control system, which consists of the microprocessor
part of the UOC (7200), is linked to the external devices (Tuner,
NVM, Audio ICs, etc) by means of the I2C-bus. An internal I2C-
bus is used to control other signal processing functions, like
video processing, sound IF, vision IF, synchronization, etc.
9.8.2 User Interface
The chassis uses a remote control with RC5 protocol. The
incoming signal is connected to pin 67 of the UOC.
The keyboard, connected to UOC pin 8, can also control the
set. Button recognition is done via a voltage divider.
The front LED (6691) is connected to an output control line of
the microprocessor (pin 11). It is activated to provide the user
information about whether or not the set is working correctly
(e.g., responding to the remote control, normal operation (USA
only) or fault condition)
9.8.3 I/O Selection
For the control of the input and output selections, there are
three lines:
STATUS1
This signal provides information to the microprocessor on
whether a video signal is available on the SCART1 AV input
and output port (only for Europe). This signal is not connected
in LATAM/NAFTA sets.
STATUS2
This signal provides information to the microprocessor on
whether a video signal is available on the SCART2 AV input
and output port (only for Europe).
For sets with an SVHS input it provides the additional
information if a Y/C or CVBS source is present.
The presence of an external Y/C source makes this line 'high'
while a CVBS source makes the line 'low'.
SEL_AV1_AV2
This is the source select control signal from the
microprocessor. This control line is under user control or can
be activated by the other two control lines.
9.8.4 Power Supply Control
The Power Supply is interfaced with the microcontroller (UOC)
to provide the power supply with the control signals required for
burst mode operation in standby and to vary the picture width
by adjusting V_BAT.
The microprocessor part is supplied with 3.3 V and 8 V. The 3.3
V is derived from the "V_aux/V_audio" voltage via a 3V3
stabilizer (7493). The 8 V is derived from the 33V tuner voltage
via TS7491 and TS7496.
Two signals are used to control the power supply: STD_CON
and PW_ADJ.
STD_CON
This signal is generated by the microprocessor when over-
current takes place at the "Main" line. This is done to enable the
power supply into standby burst mode, and to enable this mode
during a protection.
This is of logic "high" (3.3 V) under normal operation of the TV.
When the TV set is in Standby (or fault) condition, this signal is
a continuous pulse of 5 ms "low" (0 V) and 5 ms "high".
Note: In the L01 chassis this was inverted.
Figure 9-2 Block diagram of power supply interface with UOC
PW_ADJ
This signal is generated by the UOC through a PWM port. This
PWM port is configured in Push Pull mode to generate a square
wave signal of 0 to 100% duty cycle with a default value of 50%
duty cycle.
PW_ADJ will eliminate tolerance and can adjust the picture
wide slightly.
9.8.5 Protection Events
Several protection events are controlled by the UOC. In case
one of these protections is activated, the set will go to
"Standby" mode.
Deflection protections
The main protections for deflection are X-ray protection, frame
amplifier failure detection, black current loop stability
protection, and +8V auxiliary supply protection. For X-ray
protection, the X-ray detection bit, XDT, must always be set to
"1" (detection mode). High EHT protection must be triggered
via software upon detection of the XPR bit switching to "1".
A suitable number of checks are done before putting the set
into protection mode in order to prevent false triggering.
For service requirements, the Enable Vertical Guard (RGB
blanking), EVG, can be disabled (set to "0") although this is not
necessary.
The following bits are monitored:
• SUP (Supply voltage indication)
• XPR (X-ray protection)
• EVG (Enable Vertical Guard)
• NDF (Output Vertical Guard)
• BCF (Black Current Failure)
I2C protection
To check whether all I2C IC's are functioning.
POWER SUPPLY
BLOCK WITH
TEA 1506
CONTROL IC
UOCAC INPUT
Std_Con
+3V3
PW_ADJ
CL 36532044_039.eps
180603