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2004 Jan 26 15
Philips Semiconductors Product specification
MPEG-2 video and MPEG-audio/AC-3
audio encoder with multiplexer
SAA6752HS
7 FUNCTIONAL DESCRIPTION
7.1 System operation
7.1.1 GENERAL
The SAA6752HS has a multi-processor architecture.
The different processing and control modules are not
locked to each other but run independently within the limits
of the global scheduling. The data transfer between the
processing units is carried out via FIFO memories or the
external SDRAM. The device is configured and the
operation modes are selected via the I
2
C-bus.
7.1.2 OPERATING MODES
There are five operating modes:
1. Idle. This mode is set after applying a hard reset (i.e.
on power-up). In this mode the SAA6752HS can be
initialized by the host to the required configuration.
Video and audio processing is disabled. A hard reset
always resets the SAA6752HS configuration
parameters back to the default states.
2. Stop. In Stop mode, the video and audio input
processing is enabled but the multiplexer output
remains disabled. It is possible to read status
information on the input video and audio signals via
the I
2
C-bus. The SAA6752HS initialization settings
cannot be modified, except to some specific dynamic
encoding parameters (i.e. bit rate setting).
3. Encode. In this mode, the multiplexer output is
enabled. Like Stop mode, only dynamic encoding
parameters can be modified in this mode.
4. Paused. This mode allows the SAA6752HS to make
seamless transitions. Restarting from Paused mode
will generate a stream output with sequential time
stamps and MPEG buffer model content.
5. Power-down. In this mode, the internal clock is
disabled, sending the SAA6752HS into a
(non-functional) power saving state. A hard reset will
re-initialize the SAA6752HS.
handbook, full pagewidth
MHC130
Power-
down
Idle
SLEEP
HARD RESET
HARD RESET
Stop Encode Paused
power
applied
RECONFIGURE
RECONFIGURE
ENABLE
STOP
START
START
START
PAUSE
Fig.3 Mode transition diagram.