HDMI

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Table of Contents

1. Purpose......................................................................................................................3

2. Introduction................................................................................................................4

3. A brief description of HDMI.........................................................................................5

3.1 Infoframes...........................................................................................................6

3.1.1 Vendor Specific (VS) Infoframe.....................................................................6

3.1.2 Auxiliary Video Information (AVI) InfoFrame..................................................6

3.1.3 Source Product Descriptor (SPD) InfoFrame..................................................6

3.1.4 Audio InfoFrame............................................................................................7

3.1.5 Audio Content Protection (ACP) Packet.........................................................7

3.2 Types of Signals...................................................................................................7

4. Hardware Abstraction Layer (HAL) Architecture.........................................................8

5. Chassis.....................................................................................................................10

5.1 Chassis Control Lower (CCL)..............................................................................10

5.1.1 HDMI Signal Detection in CCL.....................................................................10

5.1.2 CCL Sequence Diagram..............................................................................12

5.2 Chassis Control Upper (CCU).............................................................................12

5.2.1 HDMI Signal Detection in CCU.....................................................................12

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5.2.2 CCU Sequence Diagram..............................................................................13

6. Debugging and Testing.............................................................................................17

6.1 Debug Signal Detection in Chassis....................................................................17

6.2 Useful commands to debug HDMI.....................................................................18

7. HDMI Driver..............................................................................................................20

7.1 Function summary.............................................................................................20

7.2 HDMI driver debugging......................................................................................20

8. Terminology..............................................................................................................22

9. References................................................................................................................23

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1. PURPOSE

This document provides an overall description of HDMI component.

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2. INTRODUCTION

HDMI (High-Definition Multimedia Interface) is a compact audio/video interface for transmitting uncompressed digital data. It is a digital alternative to consumer analog standards, such as radio frequency (RF) coaxial cable, composite video, S-Video, SCART, component video to compatible digital audio devices, computer monitors, video projectors, and digital televisions.

HDMI follows the EIA/CEA-861 standards. HDMI supports, on a single cable, any uncompressed TV or PC video format, including standard, enhanced, and high-definition video; up to 8 channels of compressed or uncompressed digital audio; a Consumer Electronics Control (CEC) connection; and an Ethernet data connection. The CEC allows HDMI devices to control each other when necessary and allows the user to operate multiple devices with one remote control handset. Because HDMI is electrically compatible with the CEA-861 signals used by Digital Visual Interface (DVI), no signal conversion is necessary, nor is there a loss of video quality when a DVI-to-HDMI adapter is used. As an uncompressed CEA-861 connection, HDMI is independent of the various digital television standards used by individual devices, such as ATSC and DVB, as these are encapsulations of compressed MPEG video streams (which can be decoded and output as an uncompressed video stream on HDMI).

HDMI products started being produced for consumers in late 2003. Over 850 consumer electronics and PC companies have adopted the HDMI specification (HDMI Adopters). In Europe, either DVI-HDCP or HDMI is included in the HD ready in-store labeling specification for TV sets for HDTV, formulated by EICTA with SES Astra in 2005. HDMI began to appear on consumer HDTV camcorders and digital still cameras in 2006. Shipments of HDMI were expected to exceed that of DVI in 2008, driven primarily by the consumer electronics market.

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3. A BRIEF DESCRIPTION OF HDMI

The DTV has several hardware blocks through which an input signal is piped and processed. Figure 1 show a pictorial representation of hardware platform and explanation of each hardware block is beyond the scope of this document. There are four inputs for HDMI. All the four ports are interfaced to HDMI Equalizer Switch. The HDMI Equalizer is interfaced to processor through I2C lines. Only one HDMI port can be active at a time. In this current model VS info frame is used to detect 3D signals.

Figure 1

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3.1 INFOFRAMES

Infoframes are data structures defined in CEA-861-D that is designed to carry a variety of

auxiliary data items regarding the audio or video streams or the source device and is carried

from Source to Sink across HDMI.

3.1.1 Vendor Specific (VS) Infoframe

3D content is indicated using the Vendor Specific (VS) infoframe. It has been observed that some 3D sources stop sending the VS infoframe should their output be switched from 3D to 2D. For this reason, the application must detect when the VS infoframe has stopped being received.

3.1.2 Auxiliary Video Information (AVI) InfoFrame

Various aspects of the current video stream are indicated by the HDMI Source to the Sink with Auxiliary Video information (AVI) InfoFrame.

A Source shall always transmit an AVI InfoFrame at least once per two video fields if the Source:

is ever capable of transmitting an AVI InfoFrame or, is ever capable of transmitting YCBCR pixel encoding or, is ever capable of transmitting any colorimetry other than the transmitted video

format’s default colorimetry or, is ever capable of transmitting any xvYCC or future enhanced colorimetry or, is ever capable of transmitting any Gamut Metadata packet or, is ever capable of transmitting any video format with multiple allowed pixel

repetitions.

The AVI InfoFrame shall be transmitted even while such a Source is transmitting RGB and nonpixel-repeated video. When a Source is not explicitly required to transmit AVI InfoFrames, it is recommended that the Source transmit AVI InfoFrames.

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3.1.3 Source Product Descriptor (SPD) InfoFrame

The Source Product Description (SPD) InfoFrame is a new feature of EIA/CEA-861B. It contains information that is useful for communicating the name of the source device. This is useful for setting up source-selection-screens in the DTV Monitor.

Support of the SPD InfoFrame in the DTV Monitor is indicated by including version 3 of the CEA EDID Timing Extension in the DTV Monitor’s EDID data structure. The transmission of this InfoFrame is optional for the source device. The use of the information by the DTV Monitor is also optional. It shall not be sent more than once per video frame. If used, it is recommended that it be sent once every second.

3.1.4 Audio InfoFrame

A Source shall indicate characteristics of the active audio stream using the Channel Status bits, Burst Info and/or stream data (if present) and the Audio InfoFrame. Whenever an active audio stream is being transmitted, an accurate Audio InfoFrame shall be transmitted at least once per two video fields.

3.1.5 Audio Content Protection (ACP) Packet

A Source may use the ACP Packet to convey content-related information regarding the active audio stream.

3.2 TYPES OF SIGNALS

Basically there are 4 kinds of signals for HDMI:

1. 3D_CEThis has a VS Infoframe with different timings.

2. 2D_CENo VS Infoframe with different timings.

3. UNKNOWN_CEThis signal maybe 2D or 3D. Here 2D and 3D has same timing table but for 3D VS Infoframe will be present.

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4. HDMI-PCThese are PC (VESA) signals in HDMI format.

3.2.1 HDMI Signal Detection

When HDMI cable is inserted, we wait for interrupts from the driver. Depending on interrupts, signal detection takes place. After that HDMI driver notifies to the application.This invokes a timer of interval 100ms which monitors the 5v status change.If some event happens on the signal during transmission, interrupts are again used to communicate the same to application. Each value of the interrupt tells us which event has occurred. Depending on each interrupt, different settings are done and processed.

Once a HDMI cable is inserted or removed, the 5v status changes and this is read through a timer every 100ms. This will invoke the reset of the selected port if the selected port is not active.

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4. HDMI DRIVER

4.1 FUNCTION SUMMARY

HDMIRX driver offers the following functions.

1. Initialize HDMIRX driver2. Get HDMI information3. Watch HDMI state

And, HDMIRX driver does not offers the following functions.

4. EQSW control5. HDMI CEC

1. Initialize HDMIRX driver:

HDMIRX driver initializes HDMIRX block to receive signals. Setting get HDMI information and watch HDMI state is included in HDMIRX initialization.

And, HDMIRX driver clear signal information with EQSW control (input change).

2. Get HDMI information:

HDMIRX driver gets video/audio information and packet information for input HDMI signal.

For example, HDMI signal (TMDS clock, DDC5V), picture information, C-Bit information, each InfoFrame packet information.

3. Watch HDMI state:

HDMIRX driver watches signal state for input HDMI signal. When signal changes or signal stable, HDMIRX driver tells HAL layer.

Signal change and signal stable is interrupting from FW.

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5. TERMINOLOGY

Term Description

HDMI High Definition Multimedia Interface

HAL Hardware Abstraction Layer

MMGR Memory Manager

HDMIRX HDMI Receiver

TSP Transport Stream Processor

TMDS Transition Minimized Differential Signaling

DW Driver Wrapper

AVG Audio Video Graphics

CCL Chassis Control Lower

CCU Chassis Control Upper

CCBV Chassis Control Bridge Video

CCBH Chassis Control Bridge HDMI

APP Application

MW Middleware

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