LM9831CCVJDX datasheet(12/41 Pages) NSC

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HORIZONTAL RESOLUTION AND DATAMODE SETTINGS

Horizontal DPI Divider

This register determines the horizontal

resolution of the scan.

Scan resolution = Optical resolution divided

by the Horizontal_DPI_Divider.

00 0÷1

00 1÷1.5

01 0÷2

01 1÷3

10 0÷4

10 1÷6

11 0÷8

11 1÷12

Pixel Packing

This register determines how many bits in

each byte of data are transmitted to the host

when DataMode = 0

0 0

1 bit/pixel (1 bit grayscale/3 bit color)

0 1

2 bits/pixel (2 bit grayscale/6 bit color)

1 0

4 bits/pixel (4 bit grayscale/12 bit color)

1 1

8 bits/pixel (8 bit grayscale/24 bit color)

DataMode

When DataMode = 0, the pixel data is fully

processed, going through the Offset,

Shading, Horizontal DPI Adjust, Gamma,

and Pixel Packing blocks.

When DataMode = 1, 14 bit data is extracted

following the Shading Multiplier stage.

Gamma and any other post processing must

be done by the host.

1, 2, 4, or 8 bit image data,

as determined by the Pixel Size setting.

14 bit image data - sent in 2 bytes, MSB first:

First Byte: 13 12 11 10 09 08 07 06

Second Byte: 05 04 03 02 01 00 XX XX

(XX: bits set to 0)

RESERVED

Reserved

0 0 0 0 0 0 0 0 Write 00 to this register

SENSOR CONFIGURATION

Input Signal Polarity

0 Negative (Most CCD Sensors and Toshiba CIS)

1 Positive (Most CIS Sensors)

CDS On/Off

CDS Off

CDS On

Standard/Even-Odd Sensor

Standard (1 pixels per Ø period)

Even/Odd (2 pixels per Ø period)

CIS TR1 Timing Mode

0 0

Off - use standard CCD Timing

CIS TR1 Timing Mode 1:

TR1 pulse = exactly one Ø clock,

starting at rising edge of Ø1

CIS TR1 Timing Mode 2:

TR1 pulse = exactly one Ø clock,

TR1 centered around Ø1 high.

N/A

Fake Optical Black Pixels

(for Dyna-type CIS sensors)

Off: Normal operation

On: RS pulse held high for entire Optical Black period

Address

Function

Value

LM9831CCVJDX Datasheet(PDF) 12 Page - National Semiconductor (TI)

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