DCR-TRV900 - Sony Movie Service Manual (repair manual). Page 4

The HI controller is always monitoring the input signal from the keyboard, LANC,

SIRCS and chime, and issues the corresponding command to mechanism control-

ler, camera controller, OSD, LCD driver and others.  The HI controllers and the

DCR-TRV900 system start up in the following sequence.

1 When a battery is installed, the main power is always supplied to the HI

controller as long as the main power is turned on.  The DCR-TRV900 entire

system is reset by the HI controller.  The HI controller monitors the input

signals all the time.

2 When the POWER ON command is issued from the HI controller as acti-

vated by the key input or any other input signals, the power is supplied to the

mechanism controller, camera controller and digital still controller.

3 Then the respective ICs that are connected to each controller are reset and

start their operations.

…

When the mechanism controller receives the mode transition commands from the

HI controller, it issues the commands to control the I/F that uses the i.- LINK, to

control the tape format (TFD), to control the LINE OUT signal (A01) and to con-

trol I/F (ABC) the microphone input signal.  The respective ICs perform their

function in accordance with the commands.  Status of these ICs are fed back to the

HI controller through the input controller so that the HI controller monitors and

controls the operating mode at all times.

…

When the camera controller receives the mode transition commands from the HI

controller, it performs the following functions.

1 EEPROM (IC757) data reading and writing
2 Timing generator (IC204) control
3 VAP (IC302) control
4 FOCUS, ZOOM and ND filter control and motor control
5 Defects compensation and others

At the same time when the above controls are performed, status of each controller

is fed back to the HI controller through the camera controller.

The mechanism controller and the camera controller are connected in parallel

with respect to the HI controller.  Therefore, when any communication between

the mechanism controller and the camera controller is desired, a command needs

to be sent through the HI controller.  For example, to send a command from the

mechanism controller to the camera controller, it needs to be sent from the mecha-

nism controller to the HI controller first, then from the HI controller to the camera

controller.

…

When the digital still controller receives the mode transition commands from the

HI controller, it performs the following functions.

1 It controls the file name and the header information when writing the com-

pressed data into the PC card and others.

2 It controls the file name and the header information when reading the com-

pressed data from the PC card and others.