Hitachi 46W500 Training page 25

DP-3X MICROPROCESSOR DATA COMMUNICATIONS CIRCUIT EXPLANATION
Microprocessor Data Communications circuit diagram.
(See DP-3X Microprocessor Data Communications Circuit Diagram for Details)
The Microprocessor must keep in communication with the Chassis to maintain control over the individual cir-
cuits. Some of the circuits must return information as well so the Microprocessor will know how to respond to
different request.
The Microprocessor uses two types of communication for control, I
2
lines . The I C communication scheme only requires 2 lines for control. These lines are called SDA and SCL.
Serial Data and Serial Clock respectively.
Also, due to the fact that this Microprocessor operates at 3.3Vdc, it requires a Level Shift IC to bring the DC
level of the control lines up to make it compatible with the connected components. The Level Shift IC also brings
the DC levels down as outside circuits communicate with the microprocessor.
The Microprocessor communicates with the following ICs:
ON THE SIGNAL PWB:
•
UD2003 Digital Module (ATSC Tuner DP-36 and DP-38 Chassis Only)
•
U301 Main Tuner
•
U302 PinP Tuner
•
I003 EEPROM
•
U401 Flex Converter
•
I010 Level Shift
•
I501 Rainforest
•
IA01 Audio Control
ON THE TERMINAL PWB:
•
IY01 3D Y/C
•
IV01 A/V Selector
•
IV11 Digital to Analog Converter DAC
•
IV03 Y Pr/Pb Selector
•
IY04 Main Video Chroma Y Pr/Pb Selector
•
IY03 Sub Video Chroma Y Pr/Pb Selector
The following explanation will deal with the communication paths used between the Microprocessor and the re-
spected ICs.
ON THE SIGNAL PWB:
UD2003 Digital Tuner (ATSC Tuner) DP-36 and DP-38 Chassis Only
The Microprocessor controls the Digital Tuner via communication lines. They are listed below;
•
DM RTS (Digital Module Receive Transmission) from pin 9 of PMS1 connector to pin 27 of the I001.
•
DM CTS (Digital Module Serial Clock) bi-directional pin 20 of I001 pin 7 of the PMS1 connector.
•
DM TXD (Digital Module Transmission Data) bi-directional pin 35 of I001 pin 6 of the PMS1 connec-
tor.
•
DM RXD (Digital Module Receive Data) bi-directional pin 36 of I001 to pin 5 of the PMS1 connector.
•
Power 2 (Turns on Digital Module separate from the main Power On line) from pin 58 of I001 to pin
11 of the PMS1 connector. The Table below shows the relationship between Power_1 and Power_2.
MODE Power _1
Stand By
Timer
TV On
Power _2
Lo Lo
Lo Hi
Hi Hi
2
C Bus and the Serial Data, Clock and Load
When the Timer is set for an unattended Recording,
the Set turns on the Tuner and allows the "Video
Out (Monitor out) to become active so that a re-
cording can be made without turning on the entire
set.
(Continued on page 2)
PAGE 02-01