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3-2. BC Board Descriptions
Carries out the switching of the switches on each board and
setting of DAC data.
1. Serial Communication with Boards
The system control CPU (!Cl) carries out serial communication
with the sub CPU of each board inserted in the slots using the 4
signals-MISO,
MOSI, SLCK, and SLOT NO. It regularly
receives abnormal detection signals from the power supply
circuit and deflection circuit, and information (KILLER) for
discriminating between color and black/white for signals input
from each input adapter. It chooses who to communicate with
using the signals SLOT-0 to SLOT-7.
2. Internal Signal Generation
ICI04 to ICI 10 generates internal signals (PLUGE, 5STEP,
WHITE, ORA Y, CROSS HATCH). The clock generated by
IC121 (525 mode:14.3181 MHz, 625 mode:14.1875 MHz) is
input to IC120 (sync generator) to generate the sync signal.
3. VITC Reading
The Y/G signal is input to IC102, ICI03, and IC126, and the
VITC signal is read and input to the CPU and to display the IC7
(character generator).
The Y/G signal is input to IC124 to display the· closed caption
signal.
4. Character Generator
IC7 (character generator) is controlled to display the menu, etc.
5. Parallel Remote Control
The input signal of CNS (parallel remote control terminal) is
read by IC5 (1/0 PORT EXPANDER).
6. ISR Terminal
The CPU (ICI) carries out communication with .the ISR devices
via IC23 (serial control unit) and· IC27 and IC28 (RS232C
transceiver).
7. Serial Remote Terminal
The CPU (ICl) carries out communication with the remote
devices via IC22 (serial control unit) and IC25 and IC26
(RS485 transceiver).
8. Communication with Control Block (HC Board)
The CPU (ICI) carries out communication with the control
block (HC board) via IC14 (RS422 transceiver), receives key
input information a:nd the memory card reading data, and
transmits LED light information and the memory card writing
data.
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