SAA7205 Philips Semiconductors, SAA7205 Datasheet - Page 3

• Manufacturer Part Number: SAA7205
• Description: MPEG-2 systems demultiplexer
• Manufacturer: Philips Semiconductors

Philips Semiconductors
1
1997 Jan 21
Input data fully compliant with the Transport Stream
(TS) definition of the MPEG-2 systems specification
(International Standard; November 1994)
Input data signals: Forward Error Correction (FEC) or
descrambler interface
– modem data input bus (8-bit wide)
– valid input data indicator (PKTDATV)
– erroneous packet indicator (PKTBAD/PKTBAD)
– first packet byte indicator (PKTSYNC)
– byte strobe signal [for the asynchronous mode only
The interface can be configured to either of two modes:
– asynchronous mode; PKTBCLK < 9 MHz, for
– synchronous mode; PKTBCLK is not used for
The descrambler chip clock [DCLK (9 MHz, 33% duty
cycle)] is generated and output by the demultiplexer
External memory; standard 32K
Required typical access time
(t
Effective bit rate: f
Control Interface; 8-bit multiplexed data/address
(MDAT7 to MDAT0), memory mapped I/O (P90CE201
microcontroller parallel bus compatible), in combination
with two microcontroller interrupt signals (IRQ and NMI).
In addition, a number of address input pins
(MA9 to MA2) allow direct access to a selected set of
demultiplexer registers.
Output ports:
Video; two alternative applications;
– third party video decoder compatible (master or slave
– Philips SAA7201 compatible (via general purpose
MPEG-2 systems demultiplexer
WP
FEATURES
PKTDAT7 to PKTDAT0
(PKTBCLK)]
connection to a modem (e.g. FEC)
connection to an external descrambler operating at
9 MHz. The descrambler chip clock (9 MHz; 33%
duty cycle) is generated and output to the
demultiplexer.
horizontal or vertical sync generation)
output)
)
35 ns.
bit
72 MHz
50 ns, write pulse width
8-bit static RAM.
3
Audio; third party audio decoder, or Philips SAA2500
compatible
Audio/video; third party combined A/V decoder
compatible, (programmable)
Teletext; a Teletext Clock/Teletext Data (TTC/TTD)
based serial interface to selected teletext decoders
(e.g. SAA9042). Alternatively, this interface can be
programmed to provide data for Vertical Blanking
Interval (VBI) insertion of teletext data. The interface
therefore includes a teletext data request input (TTR).
In this mode, the interface is compatible with the
SAA7183 (EURO-DENC) TXT interface.
HS Data; high-speed data output, outputting entire
transport packets, packet payloads, PES packet
payloads, or sections (programmable) at byte clock
frequency (9 MHz). In the test mode it is capable of
outputting copies of either video, audio or other data
streams (programmable).
HS pins are combined with the general purpose
interface. The general purpose interface is bidirectional,
and can therefore, be used as an alternative transport
stream input.
Descrambler; 8-bit wide data input interface, combined
with the modem input bus. A descrambler device may
output a descrambled transport stream at 9 MByte/s.
A 9 MHz descrambler clock is generated and output by
the demultiplexer.
Microcontroller support; only for control, no specific
demultiplexing tasks are performed by the
microcontroller. However, parsing and processing of
Program Specific Information (PSI), and Service
Information (SI) is left to the microcontroller.
Error handling; stream dependent error handling
algorithms, invoked either if the PKTBAD/PKTBAD input
signal is set, or if the transport_error_indicator bit
(MPEG-2 syntax) is set or if the parser detects an
MPEG-2 syntax error. Different handling algorithms are
applied for the various output ports.
Preliminary specification
SAA7205H