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AD9393

Low Power HDMI Display Interface

Analog Devices 

TIMING

The output data clock signal is created so that its rising edge

always occurs between data transitions and can be used to latch

the output data externally.

Figure 3 shows the timing operation of the AD9393.

tPER

DATACK

tDCYCLE

tSKEW

DATA

HSOUT

Figure 3. Output Timing

HDMI RECEIVER

The HDMI receiver section of the AD9393 allows the reception

of a digital video stream (which is backward compatible with

DVI and able to accommodate video of various formats (RGB,

YCrCb 4:4:4, 4:2:2)). The receiver also allows up to eight channels

of audio. Infoframes are transmitted carrying information about

the video format, audio clocks, and many other items necessary

for a monitor to utilize fully the information stream available.

The earlier digital visual interface (DVI) format was restricted

to an RGB 24-bit color space only. Embedded in this data stream

were HSYNCs, VSYNCs, and display enable (DE) signals; but

no audio information. The HDMI specification allows trans-

mission of all the DVI capabilities, but adds several YCrCb

formats that make the inclusion of a programmable color space

converter (CSC) a very desirable feature. With this feature, the

scaler following the AD9393 can specify that it always wishes to

receive a particular format, for instance, 4:2:2 YCrCb, regardless

of the transmitted mode. If RGB is sent, the CSC can easily

convert that to 4:2:2 YCrCb while relieving the scaler of this

task.

In addition, the HDMI specification supports the transmission

of up to eight channels of S/PDIF or I2S audio. The audio infor-

mation is separated into packets and transmitted during the

video blanking periods along with specific information about

the clock frequency. Part of this audio information (audio

infoframe) tells the user how many channels of audio are being

transmitted, where the channels should be placed, information

regarding the source (make, model), and other data.

AD9393

DE GENERATOR

The AD9393 has an on-board generator for DE, for the start

of active video (SAV), and for the end of active video (EAV), all

of which are necessary for describing the complete data stream

for a BT656-compatible output. This signal alerts the following

circuitry, which are displayable video pixels.

4:4:4 TO 4:2:2 FILTER

The AD9393 contains a filter that allows it to convert a

signal from YCrCb 4:4:4 to YCrCb 4:2:2 while maintaining

the maximum accuracy and fidelity of the original signal.

Input Color Space to Output Color Space

The AD9393 can accept a wide variety of input formats and

either retain that format or convert to another. Input formats

supported are

• 4:4:4 YCrCb 8-bit

• 4:2:2 YCrCb 8-, 10-, and 12-bit

• RGB 8-bit

Output modes supported are

• 4:4:4 YCrCb 8-bit

• 4:2:2 YCrCb 8-, 10-, and 12-bit

• Dual 4:2:2 YCrCb 8-bit

Color Space Conversion (CSC) Matrix

The CSC matrix in the AD9393 consists of three identical

processing channels. In each channel, three input values are

multiplied by three separate coefficients. An offset value for

each row of the matrix and a scaling multiple for all values

are also included. Each value has a 13-bit, twos complement

resolution to ensure the signal integrity is maintained. The

CSC is designed to run at speeds up to 80 MHz supporting

resolutions up to 720p at 60 Hz. With any-to-any color space

support, formats such as RGB, YUV, YCrCb, and others are

supported by the CSC.

The main inputs, RIN, GIN, and BIN, come from the 8-bit or 12-

bit inputs from each channel. These inputs are based on the

input format detailed in Table 30 to Table 52. The mapping of

these inputs to the CSC inputs is shown in Table 6.

Table 6. CSC Port Mapping

Input Channel

R/Cr (D[23:16])

Gr/Y (D[15:8])

B/Cb (D[7:0])

CSC Input Channel

RIN

GIN

BIN

Rev. 0 | Page 9 of 40

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