Philips DVD763SA/001 Service Manual page 56

Circuit Descriptions and List of Abbreviations
– Stereo PCM data output. Two possible stereo sources
can be selected as stereo PCM output:
1. Stereo PCM coming from the STi55xx via the PCM
input on Furore.
2. Stereo or down-mix-PCM derived via a decimation
filter from the SACD-DSD signal.
– Digital audio output interface (IEC958). The IEC958
format is intended to connect the DVD736SA to a
digital receiver. No DSD signals are defined for
IEC958, therefore the 'DSD-->PCM converted' signal
is transmitted. Following two types of signals are
possible on the digital interface:
1. IEC958 data coming from the STi55xx.
2. IEC958 data (stereo or down-mix-PCM) derived
via a decimation filter from the SACD-DSD signal.
– Clock + reset input. Two different processing clocks
and a reset pulse are needed:
1. Sys_clk: System clock for data processing part,
frequency can be 27 MHz or 768*FS.
2. 384*FS: Processing clock for LLD and post
processing.
3. RESETn is an asynchronous reset and should be
low for at least 1 period of DSD_CLK.
Memory
• SDRAM.
– The size of the SDRAM is 64 Mbit.
– The SDRAM (items 7500 and 7502) has the following
functions:
– It is used by the MPEG video decoder as a frame
buffer,
– It holds the software and the variables used by it.
• Flash-ROM. Two 2MB Flash-ROMs (items 7402 and
7403) hold the DVD firmware, and are controlled by pin 186
(FLASH_OEN) of the STi55xx. It must be able to perform a
download (by disk or OS-link) in a Flash-only system.
• EEPROM. User settings, player settings, and region code
2
are stored in a 32 Kb I C EEPROM.
Audio Output
The audio interfaces available in SD4.0SA_CH are I2S and S/
PDIF for digital audio output, and I2S karaoke microphone
input.
In SACD player, two types of DACs (that are PCM DAC and
high end DSD DAC), are used on AV board.
The audio data path to both DACs is routed via the Furore 2.
I2S audio
The STi55xx is capable of 6-channel I2S output. These
channels can be configured to output 5.1 Dolby Digital, DTS,
etc.
• PCM_OUT0: Left and Right.
• PCM_OUT1: Centre and LFE (subwoofer).
• PCM_OUT2: Left and Right surround.
Two additional channels (available in STi5580 and STi5588)
are capable of providing down-mixed stereo.
S/PDIF
The S/PDIF signal level (pin 57, SPDIF_OUT) is 5V TTL at
module interface. To meet the complete S/PDIF specifications,
an external de-coupling circuit (item 7720, diagram M7) is
implemented.
I2S karaoke (optional)
The STi5580 and STi5588 have built-in karaoke processing.
The internal karaoke block accepts I2S signal, acting as the
master by generating the required KOKPCMCLK frequency.
This frequency is always 1/4 the music sampling frequency.
An external analogue-to-digital converter (ADC), acting as
slave, is required to convert the microphone signals to I2S
signals.
CD-DA/DVD Data Path
The data path for CD-DA and DVD is as follows:
DVD763SA
• I2S data from the M2 basic engine enters the STi55xx.
• The STi55xx processes the data, and sends the 6 PCM
output channels to Furore 2. The LeRi channels are directly
passed to the AV board also.
• The switch matrix of the Furore 2 sends the two incoming
stereo PCM channels (LeRi) to the AV board.
• The switch matrix of the Furore 2 sends the six incoming
PCM channels to the high end DAC board.
• The mute signal from the STti55xx is directly passed to the
AV board. This requires a patch on the mono board.
• The IEC958 output of the STi55xx is fed directly to AV
board.
The clock distribution is as follows:
• The master clock 384FS is received from the high end DAC
board.
• From this clock the 27 MHz clock for STi5580 and the
Furore 2 is derived (Video clock).
• From the 27 MHz clock the audio clock (256FS) is derived.
The STi55xx and Furore 2 use this clock. For CD-DA FS
amounts to 44.1 KHz, for DVD 48 or 96 KHz.
• In case of CD-DA, the high end DAC uses its internal clock
(384FS). In case of DVD, the switch matrix of Furore 2
sends the audio clock (256FS) to the high end DAC on AV
board.
• The AV board receives the 256FS clock.
Selection of the audio clock is done in the clock factory. For a
description of the clock factory, see paragraph 'Clock Factory'.
SACD Data Path
The data path for DSD/DST is as follows:
• I2S data from the basic engine enters the Furore 2.
• The Furore 2 processes the data. This results in 6 DSD/
DST channels.
• The switch matrix of the Furore 2 sends the 6 DSD/DST
channels to the high end DAC on AV board.
• The 6 DSD/DST channels are down mixed to a stereo PCM
signal.
• The switch matrix of the Furore 2 sends the stereo PCM
signal to the AV board.
• The mute signal from the STi55xx is directly passed to the
AV board. This requires a patch on the mono board.
The clock distribution is as follows:
• The master clock 384FS is received from the high end DAC
on AV board.
• From this clock the 27 MHz clock for Sti55xx and Furore 2
is derived (video clock).
• From the 27 MHz clock the audio clock (256FS) is derived.
The STti5580 and Furore 2 use this clock.
• The high end DAC on AV board uses its own XTAL clock
(384FS). The 256FS clock to the DAC board is switched
off, to prevent for interference.
• The AV board receives the 256FS clock.
Selection of the audio clock is done in the clock factory. For a
description of the clock factory, see paragraph 'Clock Factory'.
Video Output
Digital video (optional)
Digital YUV output is routed directly from STi55xx ports to a 24-
pin connector (item 1704). From the same connector, the
HSYNC, VSYNC and 27MHZ_CLK signals are available. The
digital YUV connector is the interface to external video
processing devices; such as high quality progressive scan
codex and high quality video DAC.
Analogue video
The STi55xx is capable of 6-channel analogue video. Three
channels (pins 25, 26 and 27) are RGB or YUV format, while
the other three channels (pins 32, 33 and 34) are Y, C, and
CVBS.
A video output buffer (see diagram M7, e.g. item 7701 for R) is
implemented: an 8MHz/16MHz selectable filter stage and a
75Ω drive stage.
9. EN 71