7
Block Diagram
There are four major stages within this DVD player. They operate in this
sequence to produce the discs’ video and audio:
· Power Supply
· Communications
· Servo Control
· Video and Audio Processing
Power Supply
The power supply block delivers five different voltages. Ever 5V is the
only voltage present when the unit is plugged into AC. Ever 5V powers
Interface IC201 to switch on the remainder of the voltages when it re-
ceives the power ON (P Cont) command.
Communications
Plug In
At plug in, Interface IC201 powers on the unit for 1.3 seconds, keeping
the display dark. During this time there is a brief communication between
Interface IC201 and System Control IC202 on the serial bus. At the con-
clusion of this communication “handshaking”, the front panel Dolby Digital
indicator lights and quickly extinguishes as the unit powers off. The front
panel red standby light is on during the entire initial communication, never
turning green when momentarily powering up at plug in.
Power ON
At power ON, the red standby light turns to green and the power supply is
turned on. After another brief communication between IC201 and IC202,
IC202 retrieves and implements the start up program stored in Flash
Memory IC205.
The start up program requires IC202 to check for the presence of these
six ICs on the parallel bus and IC501 on the serial bus:
ICs Checked During Start Up
Name Number Purpose
1. Flash ROM IC205 Start up program instructions
2. Hybrid Gate
Array
IC601 Expansion port for System Control
IC202 to indirectly communicate with
others on the parallel bus.
3. SRAM IC204 IC202’s local memory
4. AV Decoder IC401 Audio (AC-3) and Video (MPEG 2)
decoder
5. ARP2 IC303 CD/DVD data processing and
separation
6. Servo IC701 Analog servo control
7. Audio DSP IC501
Dolby Prologic, Rear channel delays,
5.1 channel downmixing to 2 channels
If an IC does not reply, IC202 instructs IC201 to power off the set.
Servo Control
At the successful conclusion of the start up program, IC202 retrieves servo
parameter data from EEProm IC201 using the serial bus. Then IC202
communicates with expansion port HGA IC601. IC601 relays the infor-
mation to other ICs connected to it. One of those ICs is IC701. Servo
IC701 is instructed to reset the base unit mechanism to the initial position
and confirm it:
· Tray closed
· Tilt servo at mid position
· Sled returned to home position
If the initial position is not confirmed before a time limit (“time out”), IC201
will power off the set. Confirmation comes from IC701 through IC601 to
IC202.
IC202 then sends commands back to servo IC701 for disc detection.
