VV5404 datasheet(14/54 Pages) STMICROELECTRONICS

14 / 54 page

VV5404 & VV6404

CD5404-6404F-A

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4.3.1 Blank lines

In addition to padding between data lines, actual blank data lines may appear in the positions indicated above. These

lines begin with start-of-blank-line embedded control sequences and are constructed identically to active video lines

except that they will contain only blank bytes (07H).

4.3.2

Black line timing

The black lines (which are used for black level calibration) are identical in structure to valid video lines except that

they begin with a start-of-black line sequence and contain either information from the sensor ‘black lines’ or blank

bytes (07H).

4.3.3

Valid video line timing

All valid video data is contained on active video lines. The pixel data appears as a continuous stream of bytes within

the active lines. The pixel data may be separated from the line header and end-of-line control sequence by a number

of ‘blank’ bytes (07H), e.g. when the border lines and pixels are disabled 07H is output in place of pixels 0, 1, 354 and

355.

4.3.4

Start of frame line timing

The start of frame line which begins each video field contains no video data but instead contains the contents of all

the serial interface registers. This information follows the start-of-line header immediately and is terminated by an

end-of-line control sequence. To ensure that no escape/sync characters appear in the sensor status/configuration

information the code 07H is output after each serial interface value. Thus it takes 256 pixel clock periods (512 system

clocks) to output all 128 of the serial interface registers. The remainder of the 356 pixel periods of the video portion

of the line is padded out using 07H values. The first two pixel locations are also padded with 07H characters (Figure 8)

If a serial interface register location is unused then 07H is output. The read-out order of the registers is independent

of whether the pixel read-out order is shuffled or un-shuffled.

4.3.5

End of frame line timing

The end of frame line which begins each video field contains no video data. Its sole purpose is to indicate the end of

a frame.

4.4

Detection of sensor using data bus state

The video processor device must have internal pull-down terminations on the data bus. On power-up a sensor will

pull all data lines high for a guaranteed period. This scheme allows the presence of a sensor on the interface to be

detected by the video processor on power-up, and the connection of a sensor to an already power-up interface (a

‘hot’ connection).

The absence of a sensor is detected by the video processor seeing more than 32 consecutive nibbles of 0H on the

data bus. On detecting the absence of a sensor, CKI, should be disabled (held low).

The presence of a sensor is detected by the video processor seeing more than 32 consecutive nibbles of FH on the

data bus. On detecting the presence of a sensor, CKI, should be enabled.

4.5

Resetting the Sensor Via the Serial Interface

Bit 2 of setup register 0 allows the VV6404 sensor to be reset to its power-on state via the 2-wire serial interface.

Setting this “Soft Reset” bit causes all of the serial interface registers including the “Soft Reset” bit to be reset to their

default values. This “Soft Reset” leaves the sensor in low-power mode and thus an “Exit Low-Power Mode” command

(Section 4.6.2) must be issued via the serial interface before the sensor will start to generate video data (Figure 9).

4.6

Power-up, Low-power and Sleep modes

To clarify the state of the interface on power-up and in the case of a ‘hot’ connection of the interface cable the power-

up state of the bus is defined below.

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