ISL51002EVALZ datasheet(24/33 Pages) RENESAS

24 / 33 page

ISL51002

FN6164 Rev 3.00

Page 24 of 33

February 29, 2012

(or 0x200 for the R (Pr) and B (Pb) channels in YPbPr mode)

during the back porch period when ABLC™ is enabled.

Functional Description

Inputs

The ISL51002 digitizes analog video inputs in both RGB and

Component (YPbPr) formats, with or without embedded sync

(SOG).

RGB Inputs

For RGB inputs, the black/blank levels are identical and equal to

0V. The range for each color is typically 0V to 0.7V from black to

white. HSYNC and VSYNC are separate signals.

Component YPbPr Inputs

In addition to RGB and RGB with SOG, the ISL51002 has an

option that is compatible with the component YPbPr video

inputs typically generated by DVD players. While the ISL51002

digitizes signals in these color spaces, it can only perform color

space conversion from RGB to YUV; if it digitizes an RGB

signal, it outputs digital RGB or YUV, while if it digitizes a

YPbPr signal, it outputs digital YCbCr, also called YUV.

The Luminance (Y) signal is applied to the Green Channel and

is processed in a manner identical to the Green input with SOG

described previously. The color difference signals Pb and Pr

are bipolar and swing both above and below the black level.

When the YPbPr mode is enabled, the black level output for

the color difference channels shifts to a mid scale value of

0x200. Setting configuration register 0x10[4] = 1 enables the

YPbPr signal processing mode of operation.

The ISL51002 can optionally decimate the incoming data to

provide a 4:2:2 output stream (configuration register

0x28[0] = 1) as shown in Table 2.

RGB to YUV Color Space Converter (CSC)

For RGB inputs, the internal Color Space Converter, when

enabled (register 0x28-bit [6] = 1), will convert from the RGB

color space to the YUV (YCbCr) color space using the following

conversion formulas:

Y = 0.299R + 0.587G + 0.114B

U = -0.172R - 0.339G + 0.511B + 512

V = 0.511R - 0.428G - 0.083B + 512

Input Coupling

Inputs can be either AC-coupled (default) or DC-coupled (See

allows video signals with substantial DC offsets to be

accurately digitized. The ISL51002 provides a complete

internal DC-restore function, including the DC restore clamp

(See Figure 1) and programmable clamp timing (registers

0x24, 0x25, and 0x26).

When AC-coupled, the DC restore clamp is applied every line,

a programmable number of pixels after the trailing edge of

HSYNC. If register 0x60[2] = 0 (the default), the clamp will not

be applied while the DPLL is coasting, preventing any clamp

voltage errors from composite sync edges, equalization pulses,

or Macrovision signals.

After the trailing edge of HSYNC, the DC restore clamp is

turned on after the number of pixels specified in the DC

Restore and ABLC™ Starting Pixel registers (0x24 and 0x25)

has been reached. The clamp is applied for the number of

pixels specified by the DC Restore Clamp Width Register

(0x26). The clamp can be applied to the back porch of the

video, or to the front porch (by increasing the DC Restore and

ABLC™ Starting Pixel registers so all the active video pixels

are skipped).

Note: The TriLevel detect for Sync on Green (SOG) utilizes the

digitized data from the selected Green video channel. If

TriLevel Sync is present, the default DC Clamp start position

will clamp at the top of the TriLevel Sync pulse giving a false

negative for TriLevel detect and clamping off the bottom half of

the green video. If you have an indication of active SOG you

must move the clamp start to a value greater than 0x30 to

check to see if the Tri-level Sync is present.

If DC-coupled operation is desired, the input to the ADC will be

the difference between the input signal (RIN1, for example) and

that channel’s ground reference (RGBGND1 in that example).

TABLE 1. YUV MAPPING (4:4:4)

INPUT

SIGNAL

ISL51002

INPUT

CHANNEL

ISL51002

OUTPUT

ASSIGNMENT

OUTPUT

SIGNAL

Green

Y0Y1Y2Y3

Blue

U0U1U2U3

Red

V0V1V2V3

TABLE 2. YUV MAPPING (4:2:2)

INPUT

SIGNAL

ISL51002

INPUT

CHANNEL

ISL51002

OUTPUT

ASSIGNMENT

OUTPUT

SIGNAL

Green

Y0Y1Y2Y3

Blue

Driven Low

Red

U0V0U2V2

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