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Communications
Before normal communications can begin, start-timing pulses are needed.
Then Data and Clock (I
2
C) communications will run as long as the set is
powered ON.
Start
Once the TV is powered ON, Set +9Vdc is available to the Y/C Jungle
IC301 at pin 44. Then IC301's internal oscillator starts, making horizon-
tal and vertical drive signals and a 60Hz Vertical Timing (VTIM) pulse
from pin 5. This 60Hz VTIM pulse begins the communications by telling
IC001 when to begin sending out Data and Clock signals.
Run
Memory Retrieval
Micro IC001 first communicates with the memory IC003. TV settings
were stored into memory IC003 the each time they are changed while
the TV was ON. At power ON, IC001 sends out clock and data commu-
nications to Memory IC003 to retrieve this information. The return data is
sent back to IC001 on the same data line (IC001/pin 36 – IC003/pin 5)
and is supported by clock signal from IC001/pin 39.
User Settings Transferred from Memory
The user settings stored in memory will include:
•
TV station – last station used, CC, channel block, favorites
•
Input Selection - Video 1, Video 2, or TV input
•
Picture settings – Brightness, color, sharpness, etc. (if not at default
level)
•
Volume – level, tone, balance, speaker ON/OFF
The waveform of the VTIM signal is shown preceding the IC003 memory
data and clock signals.
57
TV ON - Active channel.
Channel 1 – IC301/pin 5; VTIM
Channel 2 – IC001/pin 36; Bi-directional Data
Channel 3 – IC001/pin 39; Clock Output to IC003
Channel 4 – IC001/pin 37; Bi-directional Data
All waveforms at 5V/div.; Time base = 2msec/div.
ID Code Transferred from Memory
In addition to the user data transferred from memory into IC001, operat-
ing parameters such as size, gamma, linearity, and the TV's ID codes are
also transferred.
These ID codes identify the model's features. Having the wrong codes
will permit the TV to display parts of a feature that does not exist in that
model. For instance, a video 3 may appear on the OSD when there is no
video 3 input. These ID codes are accessible for check and correction
from the service menu (see the service manual for access information
from the remote control).
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