Sony FWD-40LX1, Руководство по обслуживанию

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3-3
FWD-40LX1
The D3 board has a function that is activated from power saving by the signal input to the INPUT1
terminal (CN1400) and the sync signal and SOG signal from the INPUT2 terminal (CN1600). In
specifications, when a signal is input to the INPUT1 terminal, it is notified from a scaler (IC2300) to a
microcomputer (34-pin) for activation that the signal was input by setting an SCDT signal high. A
SYNC_IRQ signal is set high using a sync processor circuit (consisting of IC1806, IC1807, IC1802, and
IC1805) when an H/V sync signal or SOG signal is input to the INPUT2 terminal. The unit is activated
when a microcomputer (3-pin) detects that the SYNC_IRQ signal is set high.
In this unit, the frequency of an RGB signal and a component during two-screen display is measured
using the port of a microcomputer. For an RGB signal, the sync signal selected using a switch (IC1603)
is converted into a composite sync signal using a sync selection circuit (consisting of IC1800, IC1803,
and IC1804) and then input to a sync separation circuit (IC1809). For a SOG signal, the green
(composite) signal amplified using an amplifier circuit (consisting of Q1801, Q1802, Q1806, and
IC1808) is input to a sync separation circuit. In the sync separation circuit, H and V sync signals are
separated. After that, frequency measurement (H_COUNT and V_COUNT), polarity discrimination
(POL_H and POL_V), and sync signal detection (EXT_H and EXT_V) are performed to discriminate an
input signal by using each signal input to the port of a microcomputer.
The “video sync” mode is provided as the function of this unit. In this mode, a composite signal is input
from pin 13 of an INPUT2 terminal instead of a sync signal. During processing, this signal is input from
IC1604 to the composite input pin of a switch (IC1603). Using a sync separation function of IC, a signal
is input to the scaler and sync selection circuit as a composite sync signal.
This unit has an RS-232C connector (CN1006) for external communication. Using a dedicated
command, the unit can be controlled or the firmware of a microcomputer and scaler can be rewritten. By
using an interface (IC1002), the signal of an RS-232C connector is output to this unit in the range of 5 V
and to the external connection unit in the range of 12 V. IC1002 is connected with a microcomputer and
scaler using a communication selector switch (IC1004) and can be communicated using UART. External
communication can be performed from the network board (BKM-FW32/BKM-FW50) connected to
option slot 1 as well as from an RS-232C connector. In this case, the 232C_SHDN signal connected with
an option board is set low, and the input/output signal of IC1002 is set disable. The communication lines
(OP_TX and OP_RX) from the option board are connected using a communication selector switch
(IC1004).
A communication selector switch is usually connected to a microcomputer. It is connected with the
scaler only when the firmware of a scaler is rewritten. The switching can be done by setting a
GM_UPGRADE signal (at pin 27 of a microcomputer) low to a microcomputer using a dedicated
command. In this case, the GM_BINT output signal from IC1007 goes low, and a microcomputer does
not perform communication (such as rewriting of setting) with a scaler at all. To cancel this setting, pull
out and insert an AC cord, that is, reset this unit.
One of the communication functions is to rewrite the firmware of a microcomputer and scaler. A rewrite
switch (S1000) is set so that it goes low when firmware is rewritten from an RS-232C connector. (The
rewrite switch is set so that it goes high during factory setting.) As a result, a microcomputer can be
controlled from pins 6 and 8 of an RS-232C connector. When the signal at pin 6 is set high, an FWE
signal is set low and a microcomputer is set to the write mode. (The signal at pin 1 (MD2) of a
microcomputer is set low.) When the signal at pin 8 is set high, a CPU_RST signal is set high and pin 92
of a microcomputer is reset. By this pin control, the firmware of a microcomputer and scaler can be
rewritten using firmware write software.
Firmware can also be rewritten from an option board. Rewrite can be done without switching SW1000
by controlling the reset of a microcomputer using the signal line of OP_CPU_RST and the setting of a
microcomputer write mode using the signal line of OPFWE.