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Chips embed CEC to support HDMI 1.3

Posted: 01 Jul 2008 ?? ?Print Version ?Bookmark and Share

Keywords:consumer electronics control? CEC functionality? HDMI 1.3?

In an effort to help manufacturers easily add CE control (CEC) functionality to digital systems, interface chip vendors are designing transmitters and receivers, as well as switches and repeaters, with features that allow them to embed CEC capability with fewer parts into DTVs, PCs, video recorders and other A/V products.

Ease design complexity
CEC enables manufacturers to add command and control functions that, when deployed, can change the way devices behave in a system and allow users to control multiple HDMI-linked devices with a single remote control. By integrating the CEC function in the interface chip, vendors can help CE OEMs reduce component count, ease design complexity and speed time-to-market for products that support the popular HDMI 1.3 standard.

Analog Devices Inc. was one of the first vendors to produce in volume a low-power HDMI 1.3 transmitter that incorporates a CEC buffer on-chip, eliminating the need for the design engineer to develop a separate CEC support channel. Recently, several interface IC companiesincluding Silicon Image, Chrontel and RedMere Technologyhave developed chips that also offer built-in support for the CEC function.

Silicon Image, which holds roughly 85-90 percent of the discrete HDMI market, has many products in its portfolio that provide integrated CEC support. Silicon Image's products have been the first to aggressively integrate next-generation standards such as HDMI 1.3 with Deep Color and x.v.Color, as well as support for CEC and HBR (high bit rate) audio standards. Its most recent HDMI 1.3 products to provide these features include the PinnaClear SiI9223 four-port receiver and the SiI9127 two-port receiver.

The parts employ a power management scheme to ensure low standby power consumption through an innovation known as "power islands." Power islands isolate CEC and Extended Display Identification Data (EDID) functions to ensure that minimum active circuitry consume standby power. Silicon Image's low-power standby mode enables CEC and EDID to function with 5V HDMI cable power from source devices such as DVD players, STBs and game consoles.

A series of features makes it easy to integrate the SiI9223 and SiI9127 into existing HDTV designs. An auto-boot feature eliminates the need for external MCU initialization that can improve the power-on "time to picture" of HDTVs, and a software API provides the framework to reduce firmware development time.

Adding portability
The PinnaClear SiI9223 integrated receiver supports Silicon Image's new Mobile High-Definition Link, a technology that enables mobile devices such as digital cameras and camera phones to connect to and display high-definition (HD) content on DTVs.

Silicon Image also recently introduced the SiI9185, a three-to-one (3:1) switch well suited for use in the back panel of HDTVs, where consumers would plug in multiple devices, such as an HD DVD or Blu-ray player, STB or game console. The 3:1 SiI9185 TMDS switch is used to select a single HDMI or Digital Video Interface (DVI) signal from among the three HDTV receiver ports and to generate fully compliant HDMI/DVI A/V output. The switch provides support for Digital Data Channel, HD Content Protection, Hot Plug Detect (HPD) and 5V power.

High-level API
The SiI9181, meanwhile, is a one-to-one switch well suited for the front or side panel of an HDTV, where consumers would plug in an HD camcorder, digital still camera or other portable device with an HDMI port.

The PinnaClear SiI9223 is a four-port HDMI receiver that delivers advanced HDMI 1.3 HDTV features and includes HDMI-compliant CEC I/O to simplify design and lower cost.

CEC implementation in the SiI9185 and SiI9181 provides manufacturers with a high-level API to eliminate low-level implementation by the MCU. Silicon Image offers manufacturers a common API to reduce the complexity of integrating the CEC functionality, and it tests this capability through Simplay Labs to ensure solid cross-platform compatibility.

ADI's ADV7520NK is aimed at DVD players, video recorders and other mobile multimedia devices capable of supporting HD audio and video content. ADI's HDMI transmitter includes 5V-tolerant I/Os that support I2C and HPD. That support further simplifies system design and extends battery life in portable electronics by eliminating external voltage translator chips to convert I/O signals from 5V to either 1.8V or 3.3V.

Efficient design
Chrontel announced an HDMI CEC IC, the CH7322, that adds CEC functionality to DTVs, PCs, video recorders and other A/V products that support the HDMI standard. According to the company, the CH7322 is the world's first standalone CEC chip, without an EEPROM and an additional CPU chip required.

In addition to the incorporation of HDMI features into PC desktop or laptop graphic chipsets, many A/V products employ MPEG decoders or DTV-on-chip ICs that have integrated HDMI transmitters. The CH7322 allows such designs to add CEC functionality without the cost of an additional, redundant HDMI-CEC combination transmitter and CPU for CEC message processing.

The CH7322 is the world's first standalone CEC chip without an EEPROM and an additional CPU chip, according to Chrontel.

The CH7322 can also be coupled with HDMI transmitter ICs that do not integrate the CEC capability. The part can be designed into HDTVs with multiple HDMI inputs for handling CEC messages. It is compliant with HDMI 1.3a and uses a single-wire interface to transmit and receive CEC-defined opcodes that control A/V functionality on HDMI-attached products. The device is offered in a 16-pin, Pb-free SSOP package.

RedMere Technology rolled out HDMI switch and repeater products that include integrated programmable CEC MCU and EDID memory at speeds up to 3.4Gbit/s. All switch and repeater products include RedMere's Cable MagnifEye equalization technology, designed to recover signals over the full frequency range from noncompliant or long cables.

- Ismini Scouras

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