Sony HDCAM HDW-F900R Maintenance Manual page 81

1-26-5. System Control (FP-152 Board and
SS-92G Board)
FP-152 board
The FP-152 board has the FP CPU (IC816 : with built-in
flash RAM) as the sub system control for VTR.
The FP CPU (IC816) performs the following processes.
. Communication with the VTR main CPU (IC1 : SS
CPU) on the SS-92G board
The FP-152 board and the SS-92G board are connected via
the MB-1096 board. The FP CPU (IC816) and the SS CPU
(IC1) on the SS-92G board are connected by the clock signal
synchronous-type serial communication once in every field at
the frequency of about 1 MHz. The clock signal is a fixed
length of 57 bytes. The SS CPU (IC1) is used as the master
clock generator.
. Audio mode control
Audio control is performed by receiving the audio mode
information and the menu setup information from the SS
CPU (IC1) on the SS-92G board. The port of the FP CPU
(IC816) is used as the input port and the switch informa-
tion that is required for the audio mode control is input to
this port. The control output is output from the I/O EX-
PANDER IC (IC823) of the FP-152 board.
. Audio control IC
The following processes are performed by establishing
parallel communication with the audio control IC (IC404)
of the FP-152 board.
. AGC/LIMITER processing
. Gain control during manual control
. Recording/playback error correction
. LPF
. EMPHASIS/DE-EMPHASIS
. Head room level switch
. Level detection
. Internal SG ON/OFF control
. Audio delay control
The block has a circuit configuration that can isolate the
bus to enable the FP CPU (IC816) to operate even when
the main power is turned off.
. AUDIO level indication
The audio level information is supplied from the audio
control IC (IC404) of the FP-152 board, and is sent to the
SS CPU (IC1) of the SS-92G board. It has the data size of
16 bits x 4CH. The SS CPU (IC1) performs soft process-
ing such as peak detection of the 16-bit data and creates the
audio level indication data that is sent to the FP CPU
(IC816). The FP CPU (IC816) displays the audio level on
the LCD at every serial communication event.
HDW-F900R/V1 (E)
. CTL/TC/UBIT display
The ON/OFF information of the switches that are connect-
ed to the port is scanned and sent to the SS CPU (IC1) of
the SS-92G board. The SS CPU (IC1) changes the display
data in accordance with the setting conditions, and the
display data is sent to the FP CPU (IC816). The FP CPU
(IC816) displays the received data at every serial commu-
nication event.
The FP CPU (IC816) only sends the switch information to
the SS CPU (IC1), and does not create the display data.
. Watch IC control
The watch data is read from the watch IC (IC831) of the
FP-152 board, and is sent to the SS CPU (IC1) of the SS-
92G board. The SS CPU (IC1) sends also the time data to
the camera CPU (IC27) of the AT-172 board. The view-
finder uses the time data for displaying the time. When the
time of the watch is set with the use of the menu, a set of
data, a year, month, day, time and minute, is sent to the FP
CPU (IC816) in the reverse route. At the same time, the
time setting request is issued from the SS CPU (IC1). The
FP CPU (IC816) sets the time to the watch IC (IC831) and
confirms the data.
. WARNING LED control and alarm tone control
The WARNING information is supplied from the SS CPU
(IC1) of the SS-92G board that is used to turn on and off
the WARNING LED (D819) on the FP-152 board. The 1
kHz square wave output from the PWM generator circuit
inside the FP CPU (IC816), is used as the alarm tone and is
output from the FP CPU (IC816 : pin-44).
. Connection circuit with the wireless receiver (optional
equipment)
The RS-232C TRANSCEIVER (IC809) on the FP-152
board acts as the interface circuit for connection with the
wireless receiver. The FP CPU (IC816) performs the serial
communication when the optional wireless receiver is
installed, and reads the reception RF sensitivity and muting
information. This data is sent to the camera CPU (IC27) of
the AT-172 board via the SS CPU (IC1) on the SS-92G
board so that it can be viewed on the viewfinder.
. Software download function
The FP CPU (IC816) is a CPU with built-in flash memory
that enables rewriting of software.
To rewrite the software, the software that is saved in a
memory stick is read by the camera microprocessor and is
on the SS-92G board transferred to the FP CPU (IC816)
via the SS CPU (IC1) for rewriting. The FP CPU (IC816 :
pin-4) goes "H" during rewriting to release the WRITE
INHIBIT.
The FP-152 board contain the power supply control circuit.
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