Hitachi 46W500 Training page 26

DP-3X MICROPROCESSOR DATA COMMUNICATIONS CIRCUIT EXPLANATION
U301 Main Tuner (with MTS outputs).
The Microprocessor controls the Main Tuner by SDA2 (Data) and SCL2 (Clock) I
SCL2 and SDA2 lines for the Main Tuner are output from the Microprocessor at pins (31 SDA2 and 28 SCL2)
respectively. These lines go directly to the Main Tuner, SDA2 at pin (5) and SCL2 at pin (4). These lines control
band switching, programmable divider set-up information, pulse swallow tuning selection, etc...
U302 PinP Tuner (monaural only).
The Microprocessor controls the Sub Tuner by SDA2 (Data) and SCL2 (Clock) I
SCL2 and SDA2 lines for the Main Tuner are output from the Microprocessor at pins (31 SDA2 and 28 SCL2)
respectively. These lines go directly to the Main Tuner, SDA2 at pin (5) and SCL2 at pin (4). These lines control
band switching, programmable divider set-up information, pulse swallow tuning selection, etc...
I003 EEPROM
The EEPROM is ROM for many different functions of the Microprocessor. Channel Scan or Memory List, Cus-
tomer set ups for Video, Audio, Surround etc... are memorized as well. Also, some of the Microprocessors inter-
nal sub routines have variables that are stored in the EEPROM, such as the window for Closed Caption detection.
Data and Clock lines are SDA1 from pin (30) of the Microprocessor to pin (5) of the EEPROM and SCL1 from
pin (29) of the Microprocessor to pin (6) of the EEPROM. Data travels in both directions on the Data line.
Note: In this chassis, if the EEPROM is removed or defective, the Microprocessor will LOCK the picture. No
functions other that the front Power Button will work. LOCK will appear on the screen, but the customer's menu
can not be accessed.
U401 Flex Converter FC04
The projection television is capable of displaying NTSC as well as ATSC (SDTV) and HD (High Definition).
The Flex Converter is responsible for receiving any video input and converting it to 33.75 Khz output (2.14H).
This output is controlled by sync and by the customer's menu and how it is set up. The set up can be 4X3 with
grey side panels, Smooth Wide, Fill or Full and even 4X3 with Black Side panels. 16X9 for SDTV. This set will
automatically bypasses the Flex Converter completely and inputs the 1080i signal directly to the Rainforest IC
I501. This happens when a true 1080i signal or Antenna C is selected. The Flex Converter can take any NTSC, S-
In, Component, NTSC or any of the 18 formats of ATSC except 1080i which doesn't route through the Flex con-
verter. Control for the Flex Converter is Clock, Data and Enable lines. The Clock, Data and Enable lines must
be routed through the Level Shift IC I007 to be brought up to 5V.
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The Clock line for the Flex Converter is output from the Microprocessor at pin (53 Clock). Clock is input to
I007 at pins (2 Clock) and is output at pins (18) then through the PFC1 connector pin 10
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The Data line for the Flex Converter is output from the Microprocessor at pin (52 Data). Data is input to
I007 at pins (4 Data) and is output at pins (16) then through the PFC1 connector pin 11
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The Enable line for the Flex Converter is output from the Microprocessor at pin (54 FCENABLE). Enable is
input to I007 at pins (6 Enable) and is output at pins (14) then through the PFC1 connector pin 12.
Data from the Flex Converter is also sent back to the Microprocessor. Data from the Flex is sent out of the PFC1
connector pin 11 to pin 5 of I007, level shifted down to 3.3V and output at pin 15 into pin 51 of the Microproces-
sor I001.
I007 Level Shift
The Microprocessor operates at 3.3Vdc. Most of the Circuits controlled by the Microprocessor operate at 5Vdc.
The Level Shift IC steps up the DC voltage to accommodate.
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Pin 18 outputs a Clock signal, used by the Flex Converter
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Pin 14 outputs an Enable signal, used by the Flex Converter
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Pin 16 outputs a Data signal, used by the Flex Converter.
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Pin 15 outputs 3.3V Data, sent from the Flex Converter
2
C communication lines.
2
C communication lines.
(Continued on page 3)
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