Set-Top Box Using the Sony CXD1959 (POD-Host) defines the subscriber terminal equipment as consisting of a navigation device (set-top) and an external module called point-of-deployment (POD). The set-top- box (STB) consists of the necessary electronics to transport and convert broadcast signal from the plant facilities to the subscriber. An intelligent "host" inside the STB also communicates with the plant facilities to direct and steer the services. The POD is a detachable device, which could be in the form of a PC card that plugs into a PCMCIA slot on the STB. This POD module is a renewable and replaceable device that addresses the issues of Conditional Access/Security functions, as well as the signaling functions. One of the purposes of the POD module is to allow the service providers to change/upgrade their conditional access and security functions as newer technology becomes available without changing the STB. This allows the STB to become a more standard device that can be manufactured by multiple sources, resulting in competition and thus, low-cost STB. OpenCable architecture (www.opencable.com). Introduction The cable industry is evolving rapidly and creating a new generation of services to consumers. Examples of these new services are video-ondemand and high speed Internet access. The FCC’s 1996 Telecom Reform Act requires the cable industry to have the retail availability of the cable subscriber terminal equipment to assure competition and availability of set-top-boxes for the benefit of consumers. CableLab was formed to create OpenCable specifications that define interfaces between Hybrid Fiber Coax (HFC) plant facilities and OpenCable terminal equipment. The goal of these specifications is to achieve a high degree of interoperability across cable systems in North America. The FCC also mandated the separation of security and navigation functions in terminal equipment by July 2000. In addition, the FCC requires that cable operators stop deploying settop-boxes with integrated security function after January 2005. One OpenCable specification Set-Top Box Cable Tuner DEMOD e OOB I/F OOB Descrambler Transport Stream Demux MPEG-2 Dolby AC3 AV Decoder Decryption Host µC Encryption NTSC/ PAL POD Figure 1. Subscriber Terminal Equipment (Set-top Box) –1– ©Copyright 2001, Sony Electronics Inc. All rights reserved. Audio DAC TV SCTE-DVS178r3 are implemented in the POD Module. Another OpenCable specification, OpenCable Applications Platform (OCAP), defines the software layer (middleware) for the STB that makes applications and services portable regardless of the hardware or operating system software. The combination of POD and OCAP enables the development of an open market for STB platform vendors to receive services independent of the cable operators. CPU Interface With OOB traffic included, the POD Module requires more bandwidth and connections on the CPU Interface than are supported by the Data Channel alone. Two communication paths share the same pins on the PC Card connector. The POD provides the following functions: Data Channel – This channel is compliant with the Command Interface protocol of SCTEDVS064 Part B, plus the interrupt mode extension. Applications use this path when they require support from either Host or POD Module resources. – Choice of digital broadcast security – Choice of scrambling system – Choice of out-of-band signaling PC Card Compliance Extended Channel – This second communication channel only includes physical and link layers. The POD Module interface is registered to the PC Card Standard as the POD Module Custom Interface with the interface ID number (STCI_IFN) allocated to equal hexadecimal 341. If the Host is not capable of operating with the POD Module, the Host will ignore the POD Module. The POD Module presents the 16-bit PC Card memory-only interface after an application of VCC or the RESET signal. When operating in this configuration, D7-D0 is retained as a byte-oriented I/O port, and the capability to read the Attribute Memory is retained. The purpose of the Extended Channel is to provide a communication path between the POD Module and the Host such that applications in one (e.g. Host, POD Module) can communicate with the headend via a link layer or modem function in the other (POD Module, Host), respectively. While the content and format of the messages for the Data Channel are well defined, the content and format of the messages for the Extended Channel are application-specific. Host-POD OOB Interface OpenCable requires support for out-of-band (OOB) signaling. The Host RF front-end specification provides the QPSK physical layer to support OOB (downstream and upstream) communications according to SCTE-DVS167r2 and SCTE-DVS178r3. The data link and media access control protocols for SCTE-DVS167r2 and –2– SONY CXD1959 POD Solution • 68K type host interface (asynchronous) The Sony CXD1959 POD controller resides in the STB and delivers most of the functions that are required to control the external POD module in a single chip. In particular, the CXD1959 provides the following POD interfaces required by the OpenCable specification: • Current overload input (automatic POD isolation) 32 concurrent PID filters with odd/even key pairs (32 key pairs in total) • TS switch integration includes: Two parallel TS input interfaces for connection to front-end (FEC) and POD outputs; Parallel TS output interface for connection to POD • Single Slot POD (or CAM) Interface • Compliant with SCTE DVS131, NRSS-B (SCTE IS-679 B), DAVIC v1.2 (CAO interface) & DVB-CI (CENELEC EN-50221) • Programmable Parallel/Serial TS output interface for connection to transport processor • Integrated hardware hot-swap support • Integrated DES ECB and DES CBC (DVS042) decryption cores • Control logic to support external address bus and OOB (out-of-band) buffers • Integrated DVB common descrambler core Set-top Box Cable Signal Host CPU O/P FRONT END POD INTERFACE CONTROL LER (CXD1959R) CP Decipher Signal TRANSPORT DEMUX PCMCIA Interface Copy Protected Descrambler CP Cipher POD MODUL E Figure 2. Typical CXD1959 Usage Inside STB –3– Scrambled Clear where it is decrypted and output "in-the-clear" to the transport processor. The basic operation is illustrated in figure 2. The CXD1959 provides the interface between a host CPU and the PC Card (e.g. POD). The host is able to configure the interface and read and write to the PC Card. The PC Card is one of two types: memory or I/O (e.g. POD). Memory cards are supported, as described in PC Card Standard, and POD modules as described in DVS131. The scrambled Transport Stream (TS) from the frontend demodulator is switched to a detachable CA module where it is descrambled and DES encrypted (copy protected) before being passed across the slot (PCMCIA) and back into the CXD1959R One of the key benefits of the CXD1959R is the serial transport stream (TS) option, which will reduce signal routing complexity on the printed circuit board. Another key benefit is Hot Swap Engine feature that provides the hot swap capability without software intervention. In addition, the Des/DVB options provide encryption capabilities that satisfy both the European and North American requirements. Photo 1. CXD1959 Evaluation Board year, additional higher layer (Link, transport, session and applications) software will be available from Sony. Together, this will be a complete reference design for the STB, further shortening the time-to-market factor. Cxd1959 Evaluation board Sony also offers an evaluation platform for customers to speed up their design and development process. A software device driver is provided with the evaluation board (shown Photo 1) to minimize the effort of the customer. Later this –4–