Teac TFT IDTV Service Manual

Teac TFT IDTV Service Manual Manual pdf 17 page image

1322” TFT TV Service Manual 13/10/200411.10. SDA55XX (SDA5550)11.10.1. General descriptionThe SDA55XX is a single chip teletext decoder for decoding World System Teletext data as well as VideoProgramming System (VPS), Program Delivery Control (PDC), and Wide Screen Signalling (WSS) dataused for PAL plus transmissions (Line 23). The device also supports Closed caption acquisition anddecoding. The device provides an integrated general-purpose, fully 8051-compatible Microcontroller withtelevision specific hardware features. Microcontroller has been enhanced to provide powerful features suchas memory banking, data pointers, and additional interrupts etc. The on-chip display unit for displayingLevel 1.5 teletext data can also be used for customer defined on screen displays. Internal XRAM consistsof up to16 Kbytes. Device has an internal ROM of up to 128 KBytes. ROMless versions can access up to 1MByte of external RAM and ROM. The SDA 55XX supports a wide range of standards including PAL,NTSC and contains a digital slicer for VPS, WSS, PDC, TTX and Closed Caption, an acceleratingacquisition hardware module, a display generator for Level 1.5 TTX data and powerful On screen Displaycapabilities based on parallel attributes, and Pixel oriented characters (DRCS).The 8-bit Microcontroller runs at 360 ns. cycle time (min.). Controller with dedicated hardware does most ofthe internal TTX acquisition processing, transfers data to/from external memory interface and receives/transmits data via I2C-firmware user-interface. The slicer combined with dedicated hardware stores TTXdata in a VBI buffer of 1 Kilobyte. The Microcontroller firmware performs all the acquisition tasks (hammingand parity-checks, page search and evaluation of header control bits) once per field. Additionally, thefirmware can provide high-end Teletext features like Packet-26-handling, FLOF, TOP and list-pages. Theinterface to user software is optimized for minimal overhead. SDA 55XX is realized in 0.25 microntechnology with 2.5 V supply voltage and 3.3 V I/O (TTL compatible). The software and hardwaredevelopment environment (TEAM) is available to simplify and speed up the development of the softwareand On Screen Display. TEAM stands for TVT Expert Application Maker. It improves the TV controllersoftware quality in following aspects:– Shorter time to market– Re-usability– Target independent development– Verification and validation before targeting– General test concept– Graphical interface design requiring minimum programming and controller know how.– Modular and open tool chain, configurable by customer.