SAA7219

` Conditional access descrambling Digital Video Broadcasting (DVB) compliant and MULTI2 compliant
` Stream demultiplexing: Transport Stream (TS), Packetized Elementary Stream (PES), program and proprietary streams
` Internal 32-bit MIPS RISC based Central Processing Unit (CPU) supporting MIPS16 instruction set and running at 81 MHz
` Low-power sleep modes supported across the chip
` Comprehensive driver software and development tool support
` Package: SQFP208.

1.1 External interfaces

` Versatile compressed stream input at 108 Mbits/s
` A 32-bit microcontroller extension bus supporting DRAM, SDRAM, Flash, (E)PROM and external memory mapped I/O devices. It also supports a synchronous interface to communicate with the integrated MPEG Audio Video Graphics Decoder (AVGD) SAA7215 at 40.5 Mbytes.
` An IEEE 1284 interface (Centronics) supporting master and slave modes. Usable as a general purpose port.
` An interface to IEEE 1394 devices (such as Philips PDI 1394 chip-set)
` Two UART (RS232) data ports with Direct Memory Access (DMA) capabilities (187.5 kbits/s) including hardware flow control signals RXD, TXD, RTS and CTS for modem support
` A Synchronous Serial Interface (SSI) to connect an off-chip modem analog front-end
` An elementary UART with DMA capabilities, dedicated to front panel devices for instance
` Two dedicated smart-card reader interfaces (ISO 7816 compatible) with DMA capabilities
` Two I<sup>2</sup>C-bus master/slave transceivers with DMA capabilities, supporting the standard (100 kbit/s) and fast (400 kbits/s) I<sup>2</sup>C-bus modes
` 32 general purpose, bidirectional I/O interface pins, 8 of which may also be used as interrupt inputs
` One Pulse Width Modulated (PWM) output with 8-bit resolution
` A General Purpose/High Speed (GP/HS) interface supporting stream recording through IEEE 1394 interface IC
` An extended JTAG interface for board test support.

1.2 CPU related features

The SAA7219 contains an embedded RISC CPU, which incorporates the following features:
` A 32-bit PR3930 core running at 81 MHz
` 8-kbyte, 2-way set associative instruction cache
` 4-kbyte, 4-way set associative data cache
` A programmable Low-power mode, including wake-up on interrupt
` A memory management unit with 32 odd/even entries and variable page sizes
` Multiply/accumulate/divide unit with fast multiply/accumulate for 16-bit and 32-bit operands
` Two fully independent 24-bit timers and one 24-bit timer including watchdog facilities
` A real-time clock unit (active in Sleep mode)
` Built-in software debug support unit as part of Extended Enhanced JTAG debug interface
` On-chip SRAM of 4 kbytes for storing code which needs fast execution.

1.3 MPEG-2 systems features

` Hardware based parsing of Transport Stream (TS), Philips Semiconductors program and proprietary software data streams. Maximum input rate is 108 Mbits/s.
` A real-time descrambler consisting of 3 modules:
   A control word bank containing 14 pairs (odd, even) of control words and a default control word
   The DVB descrambler core implementing the stream decipher and block decipher algorithms
   The MULTI2 descrambler algorithm implementing the CBC and OFB mode descrambling functions.
` Hardware section filtering based on 32 different Packet Identifiers (PIDs) with a flexible number of filter conditions (8 or 4-byte condition plus 8 or 4-byte mask) per PID and a total filter capacity of 40 (8-byte condition checks) or up to 80 (4-byte condition checks) filter conditions:
   4 TS/PES filters for retrieval for data at TS or PES level for applications such as subtitling, TXT or retrieval of private data
   Flexible DMA based storage of the 32 section substreams and 4 TS/PES data substreams in the external memory
` System time base management with a double counter mechanism for clock control and discontinuity handling, 2 Presentation Time Stamp (PTS)/Decoding Time Stamp (DTS) timers
` A GP/HS filter which can serve as an alternate input from for example IEEE 1394 devices. The IEEE 1394 GP/HS mode supports packet insertion and has an internal SRAM for storing 2 packets. It can also output either scrambled or descrambled TS to IEEE 1394 devices.

2.1 SAA7219 overview

The SAA7219 is part of a comprehensive source decoding kit which contains all the hardware and software required to receive and decode MPEG-2 transport streams, including descrambling, demultiplexing. In addition, it includes a PR3930 core which is a 32-bit MIPS RISC-based CPU core supporting the MIPS 16 instruction set to reduce memory requirements and several peripheral interfaces such as UARTs, I²C-bus units, an IEC 1883, and an IEEE 1284 (Centronics) interface. The SAA7219 is therefore capable of performing all controller tasks in digital television receiver applications such as set-top boxes. Furthermore, the SAA7219 is compliant to DVB and MULTI2 standards.

The SAA7219 receives transport streams through a versatile stream input interface capable of handling both byte-parallel and bit-serial streams in various formats, supporting data streams up to and including 13.5 Mbyte/s (108 Mbits/s). The stream data of SAA7219 is first applied to an on-chip descrambler incorporating a DVB descrambling algorithm, on the basis of 14 control word pairs stored in on-chip RAM. Demultiplexing is subsequently applied to the stream, to separate up to 32 individual data streams.

The demultiplexer section SAA7219 includes clock recovery and timebase management. Program Specific Information (PSI), Service Information (SI), Conditional Access (CA) messages and private data are selected and stored in external memory, for subsequent off-line processing by the internal PR3930 CPU core.

To support advanced board testing facilities the SAA7219 includes boundary scan test hardware, according to the EJTAG standard. The device features a Low-power sleep mode, which is capable of sustaining set-top box stand-by functionality, thus eliminating the need for a separate front-panel controller. The SAA7219 requires a supply voltage of 3.3 V and most devices input and output interfaces are 5 V tolerant except the extension bus which is 3.3 V only. The SAA7219 is mounted in a SQFP208 package.

2.2 SAA7219 in a DVB system

The SAA7219 has been designed to offer optimum performance when used with the SAA7215 for MPEG-2e AVG decoding.

· Synchronous bus interface transfer at 40.5 MHz on 16 bits
· SAA7215 has one dedicated SDRAM for MPEG-2e audio video handling and one for graphics and CPU data. The second memory offers high bandwidth and low latency to the SAA7219 when accessing it to download graphics or executing some applications. SAA7219 enables a high level of performance together with a low system cost by having one SDRAM for graphics and
CPU data.