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CXD2085M

1. Description of ID-1 (transmission system of additional video information, aspect ratio identification)

As shown in the table below, the additional video information consists of 14-bits data, and a 6-bit CRCC is

added to the data to form 20-bit data in total. This is carried on lines 20 and 283 in the vertical blanking area of

the NTSC video signal.

Table 1. Description of ID-1 signal

Bit No.

Description

1

2

3

4

5

6

4bits

4bits

Transmission aspect ratio

Screen display format

Not defined

Full-mode (16:9)

Letter-box

—

4:3

Normal

—

Identification information relating to the video signals and other signals (audio

signals, etc.) transmitted simultaneously with the video signals

Identification signal dependent on WORD0

Identification signal and other information dependent on WORD0

A

B

WORD0

WORD1

WORD2

"1"

"0"

(From the Provisional standard of EIAJ, CPX-1204)

can be output to OLBX (Pin 15) and O169 (Pin 16) set as the direct output pins.

ID-1 decoding

Data validity determination

Direct pin outputs

OLBX, O169

To microcomputer

14

VBVLD

CXD2085M

2

As shown in the figure above, the data validity determination which detects that the valid ID signal is exist or

not, and the decoded result are obtained independently during ID-1 decoding. These two results are output to

the direct output pins after taking their logical AND.

by simply outputting this data directly to the pins or by taking the logical AND as above.

In addition, performing the processing when the data validity determination (VBVLD) is "1" and the decoding

results bits 1 and 2 are "0" allows the video to be identified as 4:3 video.

3. General-Purpose I/O Port Function

I/O ports. The three types of setting are available; both two pins for inputs, for outputs, and one for input and

input ports. Perform the power-on reset by XRST when there is a possibility that the IC external circuit and the

OLBX and O169 signals could collide. Be sure to set the OLBX and O169 pins as the output pins when they

are not used.