MT9D131C12STCH-GEVB - ON Semiconductor

November, 2016 − Rev. 9

1Publication Order Number:

MT9D131/D

MT9D131

1/3.2-Inch

System‐On‐A‐Chip (SOC)

CMOS Digital Image Sensor

General Description

The ON Semiconductor MT9D131 is a 1/3.2 inch, 2 Mp CMOS

image sensor with an integrated advanced camera system. The camera

system features a microcontroller (MCU) and a sophisticated image

flow processor (IFP) with a real-time JPEG encoder.

The microcontroller manages all components of the camera system

and sets key operation parameters for the sensor core to optimize the

quality of raw image data entering the IFP. The sensor core consists of

an active pixel array of 1668 x 1248 pixels, programmable timing and

control circuitry including a PLL, analog signal chain with automatic

offset correction and programmable gain, and two 10-bit A/D

converters (ADC). The entire system-on-a-chip (SOC) has ultra-low

power requirements and superior low-light performance that is

particularly suitable for surveillance applications.

The excellent low-light performance of MT9D131 is one of the

hallmarks of ON Semiconductor’s breakthrough low-noise CMOS

imaging technology that achieves CCD image quality (based on

signal-to-noise ratio and low-light sensitivity) while maintaining the

inherent size, cost, power consumption, and integration advantages of

CMOS.

Feature Overview

The MT9D131 is a color image sensor with a Bayer color filter

arrangement. Its basic characteristics are described in Table 1.

The MT9D131 has an embedded phase-locked loop oscillator (PLL)

that can be used with the common wireless system clock. When in use,

the PLL adjusts the incoming clock frequency, allowing the MT9D131

to run at almost any desired resolution and frame rate. To reduce

power consumption, the PLL can be bypassed and powered down.

Low power consumption is a very important requirement for all

components of wireless devices. The MT9D131 has numerous power

conserving features, including an ultra low-power standby mode and

the ability to individually shut down unused digital blocks.

Another important consideration for wireless devices is their

electromagnetic emission or interference (EMI). The MT9D131 has a

programmable I/O slew rate to minimize its EMI and an output FIFO

to eliminate output data bursts.

The advanced IFP and flexible programmability of the MT9D131

provide a variety of ways to enhance and optimize the image sensor

performance. Built-in optimization algorithms enable the MT9D131

to operate at factory settings as a fully automatic, highly adaptable

camera. However, most of its settings are user-programmable.

Applications

•Network Security Cameras

•ePTZ Cameras

www.onsemi.com

See detailed ordering and shipping information on page 4 of

this data sheet.

ORDERING INFORMATION

48 CLCC

CASE TBD

•

High Resolution Security Camera

•

Wireless Cameras

•

Consumer Video Products

Features

•

Superior Low-light Performance

•

Ultra-low-power, Cost Effective

•

Internal Master Clock Generated by on-chip

Phase- locked Loop Oscillator (PLL)

•

Electronic Rolling Shutter (ERS),

Progressive Scan

•

Integrated Image Flow Processor (IFP) for

Single-die Camera Module

•

Automatic Image Correction and

Enhancement, Including Lens Shading

Correction

•

Arbitrary Image Decimation with

Anti-aliasing

•

Integrated Real-time JPEG Encoder

•

Integrated Microcontroller for Flexibility

•

Two-wire Serial Interface Providing Access

to Registers and Microcontroller Memory

•

Selectable Output Data Format: ITU-R

BT.601 (YCbCr), 565RGB, 555RGB,

444RGB, JPEG 4:2:2, JPEG 4:2:0, and raw

10-bit

•

Output FIFO for Data Rate Equalization

•

Programmable I/O Slew Rate

MT9D131

www.onsemi.com

TABLE OF CONTENTS

Ordering Information 4..............................................................................

Typical Connection 4................................................................................

Signal Description 5................................................................................

Architecture Overview 6.............................................................................

Registers and Variables 13............................................................................

Registers 14.......................................................................................

IFP Registers, Page 1 26.............................................................................

JPEG Indirect Registers 45...........................................................................

Output Format and Timing 61.........................................................................

Sensor Core 66.....................................................................................

Feature Description 72...............................................................................

Firmware 80.......................................................................................

Start-Up and Usage 84...............................................................................

Spectral Characteristics 93...........................................................................

Electrical Specifications 95...........................................................................

Appendix A: Two-Wire Serial Register Interface 98.......................................................

MT9D131

www.onsemi.com

TABLE 1. KEY PERFORMANCE PARAMETERS

Parameter Typical Value

Optical format 1/3.2-inch (4:3)

Full resolution 1600 x 1200 pixels (UXGA)

Pixel size 2.8 μm x 2.8 μm

Active pixel array area 4.73 mm x 3.52 mm

Shutter type Electronic rolling shutter (ERS)

Maximum frame rate 15 fps at full resolution,

30 fps in preview mode,

(800 x 600)

Maximum data rate/

master clock

80 Mp/s

6–80 MHz

Supply voltage Analog 2.5−3.1 V

Digital 1.7−1.95 V

I/O 1.7−3.1 V

PLL 2.5−3.1 V

ADC resolution 10−bit, on-die

Responsivity 1.0 V/lux-sec (550 nm)

Dynamic range 71 dB

SNRMAX 42.3 dB

Power consumption

348 mW at 15 fps, full resolution

223 mW at 30 fps, preview mode

Operating temperature –30°C to +70°C

Package 48-pin CLCC

MT9D131

www.onsemi.com

ORDERING INFORMATION

TABLE 2. AVAILABLE PART NUMBERS

Part Number Product Description Orderable Product Attribute Description

MT9D131C12STC−DP 2.0 MP 1/3” SOC Dry Pack with Protective Film

MT9D131C12STC−DR 2.0 MP 1/3” SOC Dry Pack without Protective Film

MT9D131C12STC−TP 2.0 MP 1/3” SOC Tape & Reel with Protective Film

MT9D131D00STCK15LC1−305 2.0 MP 1/3” SOC Die Sales, 305 μm Thickness

TYPICAL CONNECTION

VDDQV

DD VDDPLL VAA

Two-Wire

Serial Bus

6 MHz−80 MHz

Clock

EXTCLK

RESET#

STANDBY

TEST2

SADDR

SCLK

SDATA

DOUT0−DOUT7

LINE_VALID

FRAME_VALID

PIXCLK

To CMOS

Camera Port3

AGND

DGND VDDQ4

VDD4

VDDPLL4

VAAPIX4

VAA4

1KΩ

10μF

1.5 KΩ1

Figure 1. Typical Configuration (Connection)

Notes:

1. 1. Resistor value 1.5 KΩ is recommended, but may be greater for slower two-wire speed.

2. TEST must be connected to digital ground for normal device operation.

3. See “Standby Hardware Configuration”.

4. All power supply pads must be used.

MT9D131

www.onsemi.com

SIGNAL DESCRIPTION

TABLE 3. SIGNAL DESCRIPTION

Name Type Description Note

EXTCLK Input Master clock signal (can either drive the on-chip PLL or bypass it).

RESET_BAR Input Master reset signal, active LOW.

STANDBY Input Controls sensor’s standby mode.

TEST Input Reserved for factory test. Tie to digital ground during normal operation.

SCLK Input Two-wire serial interface clock.

SADDR Input Selects device address for the two-wire serial interface. The address is

0x90 when SADDR is tied LOW, 0xBA if tied HIGH. See also R0x0D:0[10].

DOUT0−DOUT7 Output Eight-bit image data output or most significant bits (MSB) of 10-bit sensor

bypass mode.

FRAME_VALID Output Identifies rows in the active image. 1

LINE_VALID Output Identifies lines in the active image. 1

PIXCLK Output Pixel clock. To be used for sampling DOUT, FRAME_VALID, and

LINE_VALID.

SDATA I/O Two-wire serial interface data.

VDD Supply Digital power (1.8V).

VDDPLL Supply PLL power (2.8V).

VAA Supply Analog power (2.8V).

VAAPIX Supply Pixel array power (2.8V).

VDDQ Supply I/O power (nominal 1.8V or 2.8V).

VDDGPIO Supply I/O power for GPIO (nominal 1.8V or 2.8V).

AGND Supply Analog ground.

DGND Supply Digital, I/O, and PLL ground.

1. 1. See “Standby Hardware Configuration”.

MT9D131

www.onsemi.com

Figure 2. 48-Pin CLCC Pinout Diagram

DGND

DOUT7

DOUT5

DOUT6

DOUT4

VDD

DGND

DOUT3

DOUT2

DOUT1

DOUT0

DGND

VDDC

FRAME_VALID

VDD

LINE_VALID

PIXCLK

SDATA

DGND

VDDQ

DGND

VDDPLL

EXTCLK

RESET#

STANDBY

DGND

VDD

SADDR

SCLK

VAA

AGND

DGND

VAAPIX

VDD

DGND

VDDQ

TEST

DGND

19 20 21 22 23 24 25 26 27 28 29 30

654321474645444342

ARCHITECTURE OVERVIEW

Color Pipeline JPEG

SRAMMicrocontrollerROM

Internal Register Bus

Interpolation

Line Buffers

JPEG

Line Buffers

Other JPEG

Memories

Decimator

Line Buffers

Sensor

Core

Image Flow Processor

PLL Stats Engine

Figure 3. Block Diagram

Sensor Core

The MT9D131 sensor core is based on ON

Semiconductor’s MT9D011, a stand-alone, 2-megapixel

CMOS image sensor with a 2.8mm pixel size. Both image

sensors have the same optical size (1/3.2 inches) and

maximum resolution (UXGA). Like the MT9D011, the

MT9D131 sensor core includes a phase-locked loop

oscillator (PLL), to facilitate camera integration and

minimize the system cost for surveillance applications.

When in use, the PLL generates internal master clock signal

whose frequency can be set higher than the frequency of

external clock signal EXTCLK. This allows the MT9D131

to run at any desired resolution and frame rate up to the

specified maximum values, irrespective of the EXTCLK

frequency.

MT9D131

www.onsemi.com

Color Pipeline

Test Pattern

Line Bu ers

Lens Shading Correction

with Digital Gain

Digital Gain

Defect Correction

Black Level Subtraction

Interpolation and

Edge Detection

Decimator

YUV Processing

Gamma Correction

YUV−to−RGB/YUV Conversion

CCM and Aperture

Correction

Format Output

AE Statistics

MEASUREMENT ENGINE

DATA, SYNC IN

DATA, SYNC OUT

Figure 4. Color Pipeline

Test Pattern

During normal operation of MT9D131, a stream of raw

image data from the sensor core is continuously fed into the

color pipeline. For test purposes, this stream can be replaced

with a fixed image generated by a special test module in the

pipeline. The module provides a selection of test patterns

sufficient for basic testing of the pipeline.

Black Level Conditioning and Digital Gain

Image stream processing starts with black level

conditioning and multiplication of all pixel values by a

programmable digital gain.

Lens Shading Correction

Inexpensive lenses tend to produce images whose

brightness is significantly attenuated near the edges.

Chromatic aberration in such lenses can cause color

variation across the field of view. There are also other factors

causing fixed-pattern signal gradients in images captured by

image sensors. The cumulative result of all these factors is

known as lens shading. The MT9D131 has an embedded

lens shading correction (LC) module that can be

programmed to precisely counter the shading effect of a lens

on each RGB color signal. The LC module multiplies RGB

signals by a two-dimensional correction function F(x,y),

whose profile in both x and y direction is a piecewise

quadratic polynomial with coefficients independently

programmable for each direction and color.

Line Buffers

Several data processing steps following the lens shading

correction require access to pixel values from up to 8

consecutive image lines. For these lines to be

MT9D131

www.onsemi.com

simultaneously available for processing, they must be

buffered. The IFP includes a number of SRAM line buffers

that are used to perform defect correction, color

interpolation, image decimation, and JPEG encoding.

Defect Correction

The IFP performs on-the-fly defect correction that can

mask pixel array defects such as high-dark-current (“hot”)

pixels and pixels that are darker or brighter than their

neighbors due to photoresponse nonuniformity. The defect

correction algorithm uses several pixel features to

distinguish between normal and defective pixels. After

identifying the latter, it replaces their actual values with

values inferred from the values of nearest same-color

neighbors.

Color Interpolation and Edge Detection

In the raw data stream fed by the sensor core to the IFP,

each pixel is represented by a 10-bit integer number, which,

to make things simple, can be considered proportional to the

pixel’s response to a one-color light stimulus, red, green or

blue, depending on the pixel’s position under the color filter

array. Initial data processing steps, up to and including the

defect correction, preserve the one-color-per-pixel nature of

the data stream, but after the defect correction it must be

converted to a three-colors-per-pixel stream appropriate for

standard color processing. The conversion is done by an

edge-sensitive color interpolation module. The module pads

the incomplete color information available for each pixel

with information extracted from an appropriate set of

neighboring pixels.

The algorithm used to select this set and extract the

information seeks the best compromise between

maintaining the sharpness of the image and filtering out

high-frequency noise. The simplest interpolation algorithm

is to sort the nearest eight neighbors of every pixel into three

sets-red, green, and blue: discard the set of pixels of the same

color as the center pixel (if there are any): calculate average

pixel values for the remaining two sets, and use the averages

instead of the missing color data for the center pixel. Such

averaging reduces high-frequency noise, but it also blurs and

distorts sharp transitions (edges) in the image. To avoid this

problem, the interpolation module performs edge detection

in the neighborhood of every processed pixel and,

depending on its results, extracts color information from

neighboring pixels in a number of different ways. In effect,

it does low-pass filtering in flat-field image areas and avoids

doing it near edges.

Color Correction and Aperture Correction

To achieve good color fidelity of IFP output, interpolated

RGB values of all pixels are subjected to color correction.

The IFP multiplies each vector of three pixel colors by a 3

x 3 color correction matrix. The three components of the

resulting color vector are all sums of three 10-bit numbers.

Since such sums can have up to 12 significant bits, the bit

width of the image data stream is widened to 12 bits per color

(36 bits per pixel). The color correction matrix can be either

programmed by the user or automatically selected by the

auto white balance (AWB) algorithm implemented in the

IFP. Color correction should ideally produce output colors

that are independent of the spectral sensitivity and color

cross-talk characteristics of the image sensor. The optimal

values of color correction matrix elements depend on those

sensor characteristics and on the spectrum of light incident

on the sensor.

To increase image sharpness, a programmable aperture

correction is applied to color corrected image data, equally

to each of the 12-bit R, G, and B color channels.

Gamma Correction

Like the aperture correction, gamma correction is applied

equally to each of the 12-bit R, G, and B color channels.

Gamma correction curve is implemented as a piecewise

linear function with 19 knee points, taking 12-bit arguments

and mapping them to 8-bit output. The abscissas of the knee

points are fixed at 0, 64, 128, 256, 512, 768, 1024, 1280,

1536, 1792, 2048, 2304, 2560, 2816, 3072, 3328, 3584,

3840, and 4095. The 8-bit ordinates are programmable

through IFP registers or public variables of mode driver (ID

= 7). The driver variables include two arrays of knee point

ordinates defining two separate gamma curves for sensor

operation contexts A and B.

YUV Processing

After the gamma correction, the image data stream

undergoes RGB to YUV conversion and, optionally, further

corrective processing. The first step in this processing is

removal of highlight coloration, also referred to as “color

kill.” It affects only pixels whose brightness exceeds a

certain preprogrammed threshold. The U and V values of

those pixels are attenuated proportionally to the difference

between their brightness and the threshold. The second

optional processing step is noise suppression by

one-dimensional low-pass filtering of Y and/or UV signals.

A 3- or 5-tap filter can be selected for each signal.

Image Cropping and Decimation

To ensure that the size of images output by MT9D131 can

be tailored to the needs of all users, the IFP includes a

decimator module. When enabled, this module performs

“decimation” of incoming images (shrinks them to

arbitrarily selected width and height without reducing the

field of view and without discarding any pixel values). The

latter point merits underscoring, because the terms

“decimator” and “image decimation” suggest image size

reduction by deleting columns and/or rows at regular

intervals. Despite the terminology, no such deletions take

place in the decimator module. Instead, it performs “pixel

binning”− divides each input image into rectangular bins

corresponding to individual pixels of the desired output

image, averages pixel values in these bins and assembles the

output image from the bin averages. Pixels lying on bin

boundaries contribute to more than one bin average: their

values are added to bin-wide sums of pixel values with

fractional weights. The entire procedure preserves all image

MT9D131

www.onsemi.com

information that can be included in the downsized output

image and filters out high-frequency features that could

cause aliasing.

The image decimation in the IFP can be preceded by

image cropping and/or image decimation in the sensor core.

Image cropping takes place when the sensor core is

programmed to output pixel values from a rectangular

portion of its pixel array - a window - smaller than the default

1600 x 1200 window. Pixels outside the selected cropping

window are not read out, which results in narrower field of

view than at the default sensor settings. Irrespective of the

size and position of the cropping window, the MT9D131

sensor core can also decimate outgoing images by skipping

columns and/or rows of the pixel array, and/or by binning

2 x 2 groups of pixels of the same color. Because decimation

by skipping (that is, deletion) can cause aliasing (even if

pixel binning is simultaneously enabled), it is generally

better to change image size only by cropping and pixel

binning.

The image cropping and decimator module can be used to

do digital zoom and pan. If the decimator is programmed to

output images smaller than images coming from the sensor

core, zoom effect can be produced by cropping the latter

from their maximum size down to the size of the output

images. The ratio of these two sizes determines the

maximum attainable zoom factor. For example, a

1600 x 1200 image rendered on a 160 x 120 display can be

zoomed up to 10 times, since 1600/160 = 1200/120 = 10.

Panning effect can be achieved by fixing the size of the

cropping window and moving it around the pixel array.

YUV-to-RGB/YUV Conversion and Output Formatting

The YUV data stream emerging from the decimator

module can either exit the color pipeline as-is or be

converted before exit to an alternative YUV or RGB data

format. See “Color Conversion Formulas” and the

description of register R0x97:1 for more details.

JPEG Encoder and FIFO

The JPEG compression engine in the MT9D131 is a

highly integrated, high-performance solution that can

provide sustained data rates of almost 80 MB/s for image

sizes up to 1600 x 1200. Additionally, the solution provides

for low power consumption and full programmability of

JPEG compression parameters for image quality control.

The JPEG encoding block is designed for continuous

image flow and is ideal for low-power applications. After

initial configuration for a target application, it can be

controlled easily for instantaneous stop/restart. A flexible

configuration and control interface allows for full

programmability of various JPEG-specific parameters and

tables.

JPEG Encoding Highlights

1. Sequential DCT (baseline) ISO/IEC 10918-1

JPEG-compliant

2. YCbCr 4:2:2 format compression

3. Programmable quantization tables

−One each for luminance and chrominance

(active)

−Support for three pairs of quantization

tables−two pairs serve as a backup for buffer

overflow

4. Programmable Huffman Tables

−2 AC, 2 DC tables−separate for luminance and

chrominance

5. Quality/compression ratio control capability

6. 15 fps MJPEG capability (header processing in

external host processor)

MT9D131

www.onsemi.com

Figure 5. JPEG Encoder Block Diagram

Re−order Line

Buffers (8Y + 8C)

Output Buffer

800 x 16

MUX

JPEG Encoder

Block

RegFile

2 x 16

IFP Register Bus

Data Unpacking

Data Packing

Spoof−frame

TIming Generator

Control Registers/Status

PCLK

DOUT[7:0]

HSYNC_/LV

VSYNC_/FV

Re−order Buffer

Controller

JPEG Input

Control

ITU−R BT. 601

Interface Control

Buffer Buffer Fullness

Detect

LD/UNLD

Control Adaptive

PCLK

SOC_DOUT (YCbCr or RGB)

Control

Memories

JPEG Encoder

Output Buffer Overflow Prevention

The MT9D131 integrates SRAM for the storage of JPEG

data. To prevent output buffer overflow, the MT9D131

implements an adaptive pixel clock (PIXCLK) rate scheme.

When the adaptive pixel clock rate scheme is enabled,

PIXCLK can run at clock frequencies of (EXTCLK freq/N1),

(EXTCLK freq/N2), (EXTCLK freq/N3), where N1, N2, N3

are register values programmed by the host through the

two-wire serial interface. A clock divider block from the

master clock EXTCLK generates the three clocks, PCLK1,

PCLK2, and PCLK3.

At the start of the frame encode, PIXCLK is sourced by

PCLK1. The buffer fullness detection block of the SOC

switches PIXCLK to PCLK2 and then to PCLK3, if

necessary, based on the watermark at the output buffer (that

is, percentage filled up). When the output buffer watermark

reaches 50 percent, PIXCLK switches to PCLK2. This

increase in PIXCLK rate unloads the output buffer at a

higher rate. However, depending on the image complexity

and quantization table setting, the compressed image data

may still be generated by the JPEG encoder faster than

PIXCLK can unload it. Should the output buffer watermark

equal 75 percent or higher, PIXCLK is switched to PCLK3.

When the output buffer watermark drops back to 50 percent,

PIXCLK is switched back to PCLK2. When the output

buffer watermark drops to 25 percent, PIXCLK is switched

to PCLK1.

When a decision to adapt PIXCLK frequency is made,

LINE_VALID, which qualifies the 8-bit data output (DOUT),

is de-asserted until PIXCLK is safely switched to the new

clock. LINE_VALID is independent of the horizontal timing

of the uncompressed imaged. Its assertion is strictly based

on compressed image data availability.

Should an output buffer overflow still occur with

PIXCLK at the maximum frequency, the output buffer and

the small asynchronous FIFO are flushed immediately. This

causes LINE_VALID to be de-asserted. FRAME_VALID is

also de-asserted.

In addition to the adaptive PIXCLK rate scheme, the

MT9D131 also has storage for three sets of quantization

tables (six tables). In the event of output buffer overflow

during the compression of the current frame, another set of

the preloaded quantization tables can be used for the

encoding of the immediate next frame. Then, the MT9D131

starts compressing the next frame starting with the nominal

PIXCLK frequency.

Output Interface

Control (Two-Wire Serial Interface)

Camera control and JPEG configuration/control are

accomplished through a two-wire serial interface. The

interface supports individual access to all camera function

registers and JPEG control registers. In particular, all tables

located in the JPEG quantization and Huffman memories are

accessible through the two-wire interface. To write to a

particular register, the external host processor must send the

MT9D131 device address (selected by SADDR or

MT9D131

www.onsemi.com

R0x0D:0[10]), the address of the register, and data to be

written to it. See “Appendix A: Two-Wire Serial Register

Interface” for a description of read sequence and for details

of the two-wire serial interface protocol.

Data

JPEG data is output in a BT656-like 8-bit parallel bus

DOUT0–DOUT7, with FRAME_VALID, LINE_VALID, and

PIXCLK. JPEG output data is valid when both

FRAME_VALID and LINE_VALID are asserted. When the

JPEG data output for the frame completes, or buffer

overflow occurs, LINE_VALID and FRAME_VALID are

de-asserted. The output clock runs at frequencies selected by

frequency divisors N1, N2, and N3 (registers R0x0E:2 and

R0x0F:2), depending on output buffer fullness.

Context and Operational Modes

The MT9D131 can operate in several modes, including

preview, still capture (snapshot), and video. All modes of

operation are individually configurable and are organized as

two contexts−context A and context B. A context is defined

by sensor image size, frame rate, resolution, and other

associated parameters. The user can switch between the two

contexts by sending a command through the two-wire serial

interface.

Preview

Context A is primarily intended for use in the preview

mode. During preview, the sensor usually outputs low

resolution images at a relatively high frame rate, and its

power consumption is kept to a minimum. Context B can be

configured for the still capture or video mode, as required by

the user. For still capture configuration, the user typically

specifies the desired output image size; for JPEG

compression, how many frames to capture, and so on. For

video, the user might select a different image size and a fixed

frame rate.

Snapshot

To take a snapshot, the user must send a command that

changes the context from A to context B. Typical sequence

of events after this command is as follows. First, the camera

exposure and white balance adjusts automatically to the

changed illumination of the scene. Next, the camera enables

JPEG compression and captures one or more frames of

desired size. Once the sequence is complete, the camera

automatically returns to context A and resumes running

preview.

Video

To start video capture, the user has to change relevant

context B settings, such as capture mode, image size, and

frame rate, and again send a context change command. Upon

receiving the command, the MT9D131 switches to the

modified context B settings, while continuing to output

YUV-encoded image data. Auto exposure automatically

switches to smooth continuous operation. To exit the video

capture mode, the user has to send another context change

command causing the sensor to switch back to context A.

Auto Exposure

The auto exposure (AE) algorithm performs automatic

adjustments of the image brightness by controlling exposure

time and analog gains of the sensor core as well as digital

gains applied to the image.

Two auto exposure algorithm modes are available:

1. Preview

2. Scene-evaluative

Auto exposure is implemented by means of a firmware

driver that analyzes image statistics collected by exposure

measurement engine, makes a decision and programs the

sensor core and color pipeline to achieve the desired

exposure. The measurement engine subdivides the image

into 16 windows organized as a 4 x 4 grid.

Preview Mode

This exposure mode is activated during preview or video

capture. It relies on the exposure measurement engine that

tracks speed and amplitude of the change of the overall

luminance in the selected windows of the image.

The backlight compensation is achieved by weighting the

luminance in the center of the image higher than the

luminance on the periphery. Other algorithm features

include the rejection of fast fluctuations in illumination

(time averaging), control of speed of response, and control

of the sensitivity to the small changes. While the default

settings are adequate in most situations, the user can

program target brightness, measurement window, and other

parameters described above.

Scene-Evaluative Algorithm

A scene-evaluative AE algorithm is available for use in

snapshot mode. The algorithm performs scene analysis and

classification with respect to its brightness, contrast, and

composure and then decides to increase, decrease, or keep

original exposure target. It makes the most difference for

backlight and bright outdoor conditions.

Auto White Balance

The MT9D131 has a built-in auto white balance (AWB)

algorithm designed to compensate for the effects of

changing spectra of the scene illumination on the quality of

the color rendition. This sophisticated algorithm consists of

two major parts: a measurement engine performing

statistical analysis of the image and a driver performing the

selection of the optimal color correction matrix, digital, and

sensor core analog gains. While default settings of these

algorithms are adequate in most situations, the user can

reprogram base color correction matrices, place limits on

color channel gains, and control the speed of both matrix and

gain adjustments. Unlike simple white balancing algorithms

found in many PC cameras, the MT9D131 AWB does not

require the presence of gray or white elements in the image

for good color rendition. The AWB does not attempt to

MT9D131

www.onsemi.com

locate “brightest” or “grayest” element of the image but

instead performs sophisticated image analysis to

differentiate between changes in predominant spectra of

illumination and changes in predominant colors of the scene.

While defaults are suitable for most applications, a wide

range of algorithm parameters can be overwritten by the user

through the serial interface.

Flicker Detection

Flicker occurs when the integration time is not an integer

multiple of the period of the light intensity. The automatic

flicker detection block does not compensate for the flicker,

but rather avoids it by detecting the flicker frequency and

adjusting the integration time. For integration times below

the light intensity period (10ms for 50Hz environment),

flicker cannot be avoided.

MT9D131

www.onsemi.com

REGISTERS AND VARIABLES

Three types of configuration controls are available:

•Hardware registers

•Driver variables

•MCU SRAM

The following convention is used in the text below to

designate registers and variables:

R0x12:1, R0x12:1[3:0] or R18:1, R18:1[3:0]

These refer to two-wire accessible register number 18, or

0x12 hexadecimal, located on page 1. [3:0] indicate bits.

Registers numbers range from 0 through FF and bits range

from 15 through 0.

•ae.Target

This refers to variable ‘Target” in the AE driver.

•SRAM 0x0400

This refers to special function register or SRAM

located at address 0x1080 in MCU memory space.

How to Access

Registers, variables are accessed in different ways.

Registers

Hardware registers are organized into several pages. Page

0 contains sensor controls. Page 1 contains color pipeline

controls. Page 2 contains JPEG, output FIFO, and more

color pipeline controls. The desired page is selected by

writing the desired value to R0xF0. After that, all READs

and WRITEs to registers from 0 through FF except R0xF0

and R0xF1, are directed to the selected page. R0xF0 and

R0xF1 are special registers and are present on all pages. See

“Appendix A: Two-Wire Serial Register Interface” for a

description of two-wire register access..

Variables

Variables are located in the microcontroller RAM

memory. Each driver, such as auto exposure, white balance,

and so on, has a unique driver ID (0...31) and a set of public

variables organized as a structure. Each variable in this

structure is uniquely identified by its offset from the top of

the structure and its size. The size can be 1 or 2 bytes, while

the offset is 1 byte.

All driver variables (public and private) can be accessed

through R0xC6:1 and R0xC8:1. While two access modes are

available (accessed by physical address and by logical

address) the public variables are typically accessed by the

logical method. The logical address, which is set in R0C6:1,

consists of a 5-bit driver ID number and a variable offset.

Examples are provided below.

To set the variable ae.Target = 50:

•The variable has a driver ID of 2. Therefore, set

R0xC6:1[12:8] = 2

•The variable has an offset of 6. Therefore, set

R0xC6:1[7:0] = 6

•This is a logical access. Therefore, set R0xC6:1[14:13]

= 01

•The size of the variable is 8 bits. Therefore, set

R0xC6:1[15] = 1

•By combining these bits, R0xC6:1 = 0xA206.

•Set R0xC8:1 = 50 for the value of the variable

To read the variable ae.Target:

•Since this is the same variable as the above example,

R0xC6:1 = 0xA206

•Read R0xC8:1 for the current variable value

MCU SRAM consists of 1K system memory and 1K user

memory. Examples of access:

•Write into user SRAM. Use to upload code

−R0xC6:1 = 0x400 // address

−R0xC8:1 = 0x1234 // write 16-bit value

•Read from user SRAM

−R0xC6:1 = 0x400 // address

−Read R0xC8:1 // read 16-bit value

See R0xC6:1 and R0xC8:1 description in Table 6, “IFP

Registers, Page 2” for more detail.

MT9D131

www.onsemi.com

REGISTERS

Sensor Core Registers

TABLE 4. SENSOR CORE REGISTER DEFAULTS

Default

PRE MCU BOOT

Default

AFTER MCU BOOT

0x00 Reserved 0x1519 0x1519

0x01 Row Start 0x001C 0x001C

0x02 Column Start 0x003C 0x003C

0x03 Row Width 0x04B0 0x04B0

0x04 Col Width 0x0640 0x0640

0x05 Horizontal Blanking B 0x015C 0x0204

0x06 Vertical Blanking B 0x0020 0x002F

0x07 Horizontal Blanking A 0x00AE 0x00FE

0x08 Vertical Blanking A 0x0010 0x000C

0x09 Shutter Width 0x04D0 N/A

0x0A Row Speed 0x00011 0x0001

0x0B Extra Delay 0x0000 0x0000

0x0C Shutter Delay 0x0000 0x0000

0x0D Reset 0x0000 0x0000

0x1F Frame Valid Control 0x0000 0x0000

0x20 Read Mode B 0x0000 0x0300

0x21 Read Mode A 0x0490 0x8400

0x22 Dark Col/Rows 0x010F 0x010F

0x23 Reserved 0x0608 0x0608

0x24 Extra Reset 0x8000 0x8000

0x25 Line Valid Control 0x0000 0x0000

0x26 Bottom Dark Rows 0x0007 0x0007

0x2B Green Gain 0x0020 N/A

0x2C Blue Gain 0x0020 N/A

0x2D Red Gain 0x0020 N/A

0x2E Green2 Gain 0x0020 N/A

0x2F Global Gain 0x0020 N/A

0x30 Row Noise 0x042A 0x042A

0x59 Black Rows 0x00FF 0x00FF

0x5B Dark G1 average N/A N/A

0x5C Dark B average N/A N/A

0x5D Dark R average N/A N/A

0x5E Dark G2 average N/A N/A

0x5F Calib Threshold 0x231D 0x231D

0x60 Calib Control 0x0080 0x0080

0x61 Calib Green1 0x0000 0x0000

0x62 Calib Blue 0x0000 0x0000

0x63 Calib Red 0x0000 0x0000

MT9D131

www.onsemi.com

TABLE 4. SENSOR CORE REGISTER DEFAULTS (continued)

Default

AFTER MCU BOOT

Default

PRE MCU BOOT

0x64 Calib Green2 0x0000 0x0000

0x65 Clock Control 0xE000 0xE000

0x66 PLL Control 1 0x2809 0x1000

0x67 PLL Control 2 0x0501 0x0500

0xC0 Global Shutter Control 0x0000 0x0000

0xC1 Start Integration (T1) 0x0064 0x0064

0xC2 Start Readout (T2) 0x0064 0x0064

0xC3 Assert Strobe (T3) 0x0096 0x0096

0xC4 De-assert Strobe (T4) 0x00C8 0x00C8

0xC5 Assert Flash 0x0064 0x0064

0xC6 De-assert Flash 0x0078 0x0078

0xE0 External Sample 1 0x0000 0x0000

0xE1 External Sample 2 0x0000 0x0000

0xE2 External Sample 3 0x0000 0x0000

0xE3 External Sampling Control 0x0000 0x0000

0xF0 Page Register 0x0000 0x0000

0xF1 Bytewise Address 0x0000 0x0000

0xF2 Context Control 0x000B 0x0000

0xFF Reserved 0x1519 0x1519

Registers

Notation used in the sensor register description table:

Sync’d to frame start

•N = No. The register value is updated and used

immediately.

•Y = Yes. The register value is updated at next frame

start as long as the synchronize changes bit is 0. Frame

start is defined as when the first dark row is read out.

By default, this is 8 rows before FRAME_VALID goes

HIGH.

Bad frame

A bad frame is a frame where all rows do not have the same

integration time, or offsets to the pixel values changed

during the frame.

•N = No. Changing the register value does not produce a

bad frame.

•Y = Yes. Changing the register value might produce a

bad frame.

YM = Yes, but the bad frame is masked out unless the

“show bad frames” feature is (R0x0D:0[8]) is enabled.

MT9D131

www.onsemi.com

TABLE 5. SENSOR CORE REGISTER DESCRIPTION

Bit

Field Description

Default

(Hex)

Sync’d to

Frame Start

Bad

Frame

R0−0x00 − Reserved (R/O)

Bits 15:0 Reserved Reserved 1519

R1−0x01 − Row Start (R/W)

Bits 10:0 Row Start

The first row to be read out, excluding any dark rows that may be

read. To window the image down, set this register to the starting Y

value. Setting a value less than 20 is not recommended because

the dark rows should be read using R0x22:0.

1C Y YM

R2−0x02 − Column Start (R/W)

Bits 10:0 Column Start

The first column to be read out, excluding dark columns that may

be read. To window the image down, set this register to the

starting X value. Setting a value below 52 is not recommended

because readout of dark columns should be controlled by

R0x22:0.

3C Y YM

R3−0x03 − Row Width (R/W)

Bits 10:0 Row Width

Number of rows in the image to be read out, excluding any dark

rows or border rows that may be read. The minimum supported

value is 2.

4B0 Y YM

R4−0x04 − Column Width (R/W)

Bits 10:0 Column Width

Number of columns in image to be read out, excluding any dark

columns or border columns that may be read. The minimum

supported value is 9 in 1 ADC mode and 17 in 2 ADC mode.

640 Y YM

R5−0x05 − Horizontal Blanking−Context B (R/W)

Bits 13:0

Horizontal

Blanking

−Context B

Number of blank columns in a row when context B is selected

(R0xF2:0[0] = 1). The extra columns are added at the beginning of

a row. See “Frame Rate Control” for more information on

supported register values.

15C Y YM

R6−0x06 − Vertical Blanking−Context B (R/W)

Bits 14:0

Vertical

Blanking

−Context B

Number of blank rows in a frame when context B is selected

(R0xF2:0[1] = 1). The minimum supported value is

(4 + R0x22:0[2:0]). The actual vertical blanking time may be

controlled by the shutter width (R0x09:0). See “Raw Data Timing”

20 Y N

R7−0x07 − Horizontal Blanking−Context A (R/W)

Bits 13:0

Horizontal

Blanking

−Context A

Number of blank columns in a row when context A is selected

(R0xF2:0[0] = 0). The extra columns are added at the beginning of

a row. See “Frame Rate Control” for more information on

supported register values.

AE Y YM

R8−0x08 − Vertical Blanking−Context A (R/W)

Bits 14:0

Vertical

Blanking

−Context A

Number of blank rows in a frame when context A is chosen

(R0xF2:0[1] = 1). The minimum supported value is (4 +

R0x22:0[2:0]). The actual vertical blanking time may be controlled

by the shutter width (R0x9:0). See “Raw Data Timing”

10 Y N

R9−0x09 − Shutter Width (R/W)

Bits 15:0 Shutter Width Integration time in number of rows. The integration time is also

influenced by the shutter delay (R0x0C:0) and the overhead time.

4D0 Y N

R10−0x0A − Row Speed (R/W)

Bits

15:14

Reserved Do not change from default value.

Bit 13 Reserved Do not change from default value.

Bit 8 Invert Pixel

Clock

Invert PIXCLK. When clear, FRAME_VALID, LINE_VALID, and

DOUT are set up relative to the delayed rising edge of PIXCLK.

When set, FRAME_VALID, LINE_VALID, and DOUT are set up

relative to the delayed falling edge of PIXCLK.

0 N N

MT9D131

www.onsemi.com

TABLE 5. SENSOR CORE REGISTER DESCRIPTION (continued)

Bit

Field

Bad

Frame

Sync’d to

Frame Start

Default

(Hex)

Description

R10−0x0A − Row Speed (R/W)

Bits 7:4 Delay Pixel

Clock

Number of half master clock cycle increments to delay the rising

edge of PIXCLK relative to transitions on FRAME_VALID,

LINE_VALID, and DOUT.

1 N N

Bit 3 Reserved Do not change from default value.

Bits 2:0 Pixel Clock

Speed

A programmed value of N gives a pixel clock period of N master

clocks in 2 ADC mode and 2*N master clocks in 1 ADC mode. A

value of “0” is treated like (and reads back as) a value of “1.”

1 Y YM

R11−0x0B − Extra Delay (R/W)

Bits 13:0 Extra Delay

Extra blanking inserted between frames. A programmed value of

N increases the vertical blanking time by N pixel clock periods.

Can be used to get a more exact frame rate. It may affect the

integration times of parts of the image when the integration time is

less than one frame. Bad frame does not occur unless integration

time is less than one frame.

0 Y N1

R12−0x0C − Shutter Delay (R/W)

Bits 13:0 Shutter Delay

The amount of time from the end of the sampling sequence to the

beginning of the pixel reset sequence. If the value in this register

exceeds the row time, the reset of the row does not complete

before the associated row is sampled, and the sensor does not

generate an image.

A programmed value of N reduces the integration time by N/2

pixel clock periods in 1 ADC mode and by N pixel clock periods in

2 ADC mode.

0 Y N

R13−0x0D − Reset (R/W)

Bit 15 Synchronize

Changes

By default, update of many registers are synchronized to frame

start. Setting this bit inhibits this update; register changes remain

pending until this bit is returned to “0.” When this bit is returned to

“0,” all pending register updates are made on the next frame start.

0 N N

Bit 10 Toggle SADDR

By default, the sensor serial bus responds to addresses 0xBA and

0xBB. When this bit is set, the sensor serial bus responds to

addresses 0x90 and 0x91. WRITEs to this bit are ignored when

STANDBY is asserted. See “Slave Address”.

0 N N

Bit 9 Restart Bad

Frames

When set, a restart is forced to take place whenever a bad frame

is detected. This can shorten the delay when waiting for a good

frame because the delay, when masking out a bad frame, is the

integration time rather than the full frame time.

0 N N

Bit 8 Show Bad

Frames

0: Outputs only good frames (default).

1: Output all frames (including bad frames).

A bad frame is defined as the first frame following a change to:

window size or position, horizontal blanking, pixel clock speed,

zoom, row or column skip, binning, mirroring, or use of border.

0 N N

Bit 7:6 Inhibit Standby

/ Drive Pins

00 or 01: setting STANDBY HIGH puts sensor into standby state

with high-impedance outputs

10: Setting STANDBY HIGH only puts the outputs in High-Z

11: Causes STANDBY to be ignored

0 N N

Bit 5 Reset SOC

When this bit is set to “1”, SOC is put in reset state. It exits this

state when the bit is set back to “0. “

Any attempt to access SOC registers in the reset state results in a

sensor hang-up. The sensor cannot recover from it without a hard

reset or power cycle.

0 N

Bit 4 Output Disable

Setting this bit to “1” puts the pin interface in a High-Z. See

“Output Enable Control”. If the DOUT*, PIXCLK, Frame_Valid, or

Line_Valid are floating during STANDBY, this bit should be set to

“0” to turn off the input buffer, reducing standby current). This bit

must work together with bit 6 to take effect.

Bit 3 Reserved Keep at default value. 0

MT9D131

www.onsemi.com

TABLE 5. SENSOR CORE REGISTER DESCRIPTION (continued)

Bit

Field

Bad

Frame

Sync’d to

Frame Start

Default

(Hex)

Description

R13−0x0D − Reset (R/W)

Bit 2 Standby

Setting this bit to “1” places the sensor in a low-power state. Any

attempt to access registers R[0xF7:0xFD]:0 in this state results in

a sensor hang-up. The sensor cannot recover from it without a

hard reset or power cycle.

0 N YM

Bit 1 Restart

Setting this bit to “1” causes the sensor to truncate the current

frame and start resetting the first row. The delay before the first

valid frame is read out is equal to the integration time. This bit is

write - “1” but always reads back as “0”.

0 N YM

Bit 0 Reset

Setting this bit puts the sensor in reset; the frame being generated

is truncated and the pin interface goes to an idle state. All internal

registers (except for this bit) go to the default power-up state.

Clearing this bit resumes normal operation.

0 N YM

R31−0x1F − FRAME_VALID Control (R/W)

Bit 15

Enable Early

FRAME_VALID

Fall

0: Default. FRAME_VALID goes low 6 pixel clocks after last

LINE_VALID.

1: Enables the early disabling of FRAME_VALID as set in bits

14:8. LINE_VALID is still generated for all active rows.

0 N N

Bits 14:8

Early

FRAME_VALID

Fall

When enabled, the FRAME_VALID falling edge occurs within the

programmed number of rows before the end of the last

LINE_VALID.

(1 + bits 14:8)*row time + constant

(constant = 3 in default mode)

The value of this field must not be larger than row width R0x03:0.

0 N N

Bit 7

Enable Early

FRAME_VALID

Rise

0: Default. FRAME_VALID goes HIGH 6 pixel clocks before first

LINE_VALID.

1: Enables the early rise of FRAME_VALID as set in bits 6:0.

0 N N

Bits 6:0

Early

FRAME_VALID

Rise

When enabled, the FRAME_VALID rising edge is set HIGH the

programmed number of rows before the first LINE_VALID:

(1 + bits 6:0)*row time + horizontal blank + constant

(constant = 3 in default mode).

0 N N

R32−0x20 − Read Mode−Context B (R/W)

Bit 15 Binning

−Context B

When read mode context B is selected (R0xF2:0[3] = 1):

0: Normal operation.

1: Binning enabled. See “Binning” and See

“Frame Rate Control” for a full description.

0 Y YM

Bit 13 Zoom Enable

0: Normal operation.

1: Zoom is enabled, with zoom factor [zoom] defined in bits

12:11.

In zoom mode, the pixel data rate is slowed by a factor of [zoom].

This is achieved by outputting [zoom − 1] blank rows between

each output row. Setting this mode allows the user to fill a window

that is [zoom] times larger with interpolated data.

The pixel clock speed is not affected by this operation, and the

output data for each pixel is valid for [zoom] pixel clocks. Every

row is followed by [zoom − 1] blank rows (with their own

LINE_VALID, but all data bits = 0) of equal time.

The combination of this register and an appropriate change to the

window sizing registers allows the user to zoom to a region of

interest without affecting the frame rate.

0 Y YM

Bits

12:11 Zoom

When zoom is enabled by bit 13, this field determines the zoom

amount:

00: Zoom 2x

01: Zoom 4x

10: Zoom 8x

11: Zoom 16x

0 Y YM

MT9D131

www.onsemi.com

TABLE 5. SENSOR CORE REGISTER DESCRIPTION (continued)

Bit

Field

Bad

Frame

Sync’d to

Frame Start

Default

(Hex)

Description

R32−0x20 − Read Mode−Context B (R/W)

Bit 10 Use 1 ADC

−Context B

When read mode context B is selected (bit 3, R0xF2:0 = 1):

0: Use both ADCs to achieve maximum speed.

1: Use 1 ADC to reduce power. Maximum readout frequency is

now half the master clock frequency, and the pixel clock is

automatically adjusted as described for the pixel clock speed

0 Y YM

Bit 9 Show Border

This bit indicates whether to show the border enabled by bit 8.

0: Border is enabled but not shown; vertical blanking is

increased by 8 rows and horizontal blanking is increased by 8

pixels.

1: Border is enabled and shown; FRAME_VALID time is

extended by 8 rows and LINE_VALID is extended by 8 pixels.

See “Pixel Border”.

0 N N

Bit 8 Over Sized

0: Normal UXGA size.

1: Adds a 4-pixel border around the active image array

independent of readout mode (skip, zoom, mirror, and so on).

Setting this bit adds 8 to the number of rows and columns in

the frame.

0 Y YM

Bit 7

Column Skip

Enable

−Context B

When read mode context B is selected (R0xF2:0[3] = 1):

0: Normal readout.

1: Enable column skip.

0 Y YM

Bits 6:5 Column Skip

−Context B

When read mode context B is selected (R0xF2:0[3] = 1) and

column skip is enabled (bit 7 = 1):

00: Column Skip 2x

01: Column Skip 4x

10: Column Skip 8x

11: Column Skip 16x

See “Column and Row Skip” for more information.

0 Y YM

Bit 4

Row Skip

Enable

−Context B

When read mode context B is selected (R0xF2:0[3] = 1):

0: Normal readout.

1: Enable row skip.

0 Y YM

Bits 3:2 Row Skip

−Context B

When read mode context B is selected (R0xF2:0[3] = 1) and Row

skip is enabled (bit 4 = 1):

00: Row Skip 2x

01: Row Skip 4x

10: Row Skip 8x

11: Row Skip 16x

See “Column and Row Skip” for more information.

0 Y YM

Bit 1 Mirror Columns

Read out columns from right to left (mirrored). When set to “1”,

column readout starts from column (column start + column size]

and continues down to [column start + 1]. When set to “0”, readout

starts at column start and continues to [column start + column size

– 1]. This ensures that the starting color is maintained.

0 Y YM

Bit 0 Mirror Rows

Read out rows from bottom to top (upside down). When set, row

readout starts from row [row start + row size] and continues down

to [row start + 1]. When clear, readout starts at row start and

continues to [row start + row size –1]. This ensures that the

starting color is maintained.

0 Y YM

R33−0x21 − Read Mode−Context A (R/W)

Bit 15 Binning

−Context A

When read mode context A is selected (R0xF2:0[3] = 0):

0: Normal operation.

1: Binning enabled. See “Binning”.

1 Y YM

Bit 10 Use 1 ADC

−Context A

When read mode context A is selected (R0xF2:0[3] = 0):

0: Use both ADCs to achieve maximum speed.

1: Use one ADC to reduce power. Maximum readout frequency

is now half of the master clock, and the pixel clock is

automatically adjusted as described for the pixel clock speed

1 Y YM

MT9D131

www.onsemi.com

TABLE 5. SENSOR CORE REGISTER DESCRIPTION (continued)

Bit

Field

Bad

Frame

Sync’d to

Frame Start

Default

(Hex)

Description

R33−0x21 − Read Mode−Context A (R/W)

Bit 7

Column Skip

Enable

−Context A

When read mode context A is selected (R0xF2:0[3] = 0):

0: Normal readout.

1: Enable column skip.

1 Y YM

Bits 6:5 Column Skip

−Context A

When read mode context A is selected (R0xF2:0[3] = 0) and

column skip is enabled (bit 7 = 1):

00: Column Skip 2x

01: Column Skip 4x

10: Column Skip 8x

11: Column Skip 16x

See “Column and Row Skip” for more information.

0 Y YM

Bit 4

Row Skip

Enable

−Context A

When read mode context A is selected (R0xF2:0[3] = 0):

0: Normal readout.

1: Enable row skip.

1 Y YM

Bits 3:2 Row Skip

−Context A

When read mode context A is selected (R0xF2:0[3] = 0) and Row

skip is enabled (bit 4 = 1):

00: Row Skip 2x

01: Row Skip 4x

10: Row Skip 8x

11: Row Skip 16x

See “Column and Row Skip” for more information.

0 Y YM

R34−0x22 − Show Control (R/W)

Bit 10 Number of Dark

Columns

The MT9D131 has 40 dark columns.

0: Read out 20 dark columns (4–23).

1: Read out 36 dark columns (4–39). Ignored during binning,

where all 40 dark columns are used.

0 N N

Bit 9 Show Dark

Columns

When set to “1”, the 20 or 36 (dependent on bit 10) dark columns

are output before the active pixels in a line. There is an idle period

of 2 pixels between readout of the dark columns and readout of

the active image. Therefore, when set to “1”, LINE_VALID is

asserted 22 pixel times earlier than normal, and the horizontal

blanking time is decreased by the same amount.

0 N N

Bit 8 Read Dark

Columns

0: When disabled, an arbitrary number of dark columns can be

read out by including them in the active image.

Enabling the dark columns increases the minimum value for

horizontal blanking but does not affect the row time.

1: Enables the readout of dark columns for use in the row-wise

noise correction algorithm. The number of columns used are

40 in binning mode, and otherwise determined by bit 10.

1 N Y

Bit 7 Show Dark

Rows

When set to “1”, the programmed dark rows is output before the

active window. FRAME_VALID is thus asserted earlier than

normal. This has no effect on integration time or frame rate.

0 N N

Bits 6:4 Dark Start

Address

The start address for the dark rows within the 8 available rows

(an offset of 4 is added to compensate for the guard pixels). Must

be set so all dark rows read out falls in the address space 0:7.

0 N N

Bit 3 Reserved Do not change from default value.

Bits 2:0 Num Dark

Rows

A value of N causes n + 1 dark rows to be read out at the start of

each frame when dark row readout is enabled

(bit 3).

7 N Y

R36−0x24 − Extra Reset (R/W)

Bit 15 Extra Reset

Enable

0: Only programmed window (set by R0x01:0 through R0x04:0)

and black pixels are read.

1: Two additional rows are read and reset above and below

programmed window to prevent blooming to active area.

1 N N

MT9D131

www.onsemi.com

TABLE 5. SENSOR CORE REGISTER DESCRIPTION (continued)

Bit

Field

Bad

Frame

Sync’d to

Frame Start

Default

(Hex)

Description

R36−0x24 − Extra Reset (R/W)

Bit 14 Next Row

Reset

When set, and the integration time is less than one frame time,

row n + 1 is reset immediately prior to resetting row n. This is

intended to prevent blooming across rows under conditions of very

high illumination.

0 N N

Bits 13:0 Reserved Do not change from default value.

R37−0x25 − LINE_VALID Control (R/W)

Bit 15 Xor

LINE_VALID

0: Normal LINE_VALID (default, no XORing of LINE_VALID).

Ineffective if continuous LINE_VALID is set.

1: LINE_VALID = “continuous” LINE_VALID XOR

FRAME_VALID.

0 N N

Bit 14 Continuous

LINE_VALID

0: Normal LINE_VALID

(default, no LINE_VALID during vertical blanking). Bad frame

1: “Continuous” LINE_VALID

(continue producing LINE_VALID during vertical blanking).

0 N N2

R38−0x26 − Bottom Dark Rows (R/W)

Bit 7 Show The bottom dark rows are visible in the image if the bit is set. 0 N N

Bits 6:4 Start Address Defines the start address within the 8 bottom dark rows. 0 N N

Bit 3 Enable

Readout Enables readout of the bottom dark rows. 0 N Y

Bits 2:0 Number of Dark

Rows

Defines the number of bottom dark rows to be used.

(The number of rows used is the specified value + 1.)

7 N Y

R43−0x2B − Green1 Gain (R/W)

Bits 11:9 Digital Gain Total gain = (bit 9 + 1)*(bit 10 + 1)*(bit 11 + 1)*analog gain

(each bit gives 2x gain).

0 Y N

Bits 8:7 Analog Gain Analog gain = (bit 8 + 1)*(bit 7 + 1)*initial gain

(each bit gives 2x gain).

0 Y N

Bits 6:0 Initial Gain Initial gain = bits 6:0*0.03125. 20 Y N

R44−0x2C − Blue Gain (R/W)

Bits 11:9 Digital Gain Total gain = (bit 9 + 1)*(bit 10 + 1)*(bit 11 + 1)*analog gain

(each bit gives 2x gain).

0 Y N

Bits 6:0 Initial Gain Initial gain = bits [6:0]*0.03125. 20 Y N

Bits 8:7 Analog Gain Analog gain = (bit 8 + 1)*(bit 7 + 1)*initial gain

(each bit gives 2x gain).

0 Y N

R45−0x2D − Red Gain (R/W)

Bits 11:9 Digital Gain Total gain = (bit 9 + 1)*(bit 10] + 1)*(bit 11 + 1)*analog gain

(each bit gives 2x gain).

0 Y N

Bits 8:7 Analog Gain Analog gain = (bit 8 + 1)*(bit 7 + 1)*initial gain

(each bit gives 2x gain).

0 Y N

Bits 6:0 Initial Gain Initial gain = bits 6:0*0.03125. 20 Y N

R46−0x2E − Green2 Gain (R/W)

Bits 11:9 Digital Gain Total gain = (bit 9 + 1)*(bit 10 + 1)*(bit 11 + 1)*analog gain

(each bit gives 2x gain).

0 Y N

Bits 8:7 Analog Gain Analog gain = (bit 8 + 1)*(bit 7 + 1)*initial gain

(each bit gives 2x gain).

0 Y N

Bits 6:0 Initial Gain Initial gain = bits 6:0*0.03125. 20 Y N

R47−0x2F − Global Gain (R/W)

Bits 11:0 Global Gain This register can be used to simultaneously set all 4 gains. When

read, it returns the value stored in R0x2B:0.

20 Y N

R48−0x30 − Row Noise (R/W)

MT9D131

www.onsemi.com

TABLE 5. SENSOR CORE REGISTER DESCRIPTION (continued)

Bit

Field

Bad

Frame

Sync’d to

Frame Start

Default

(Hex)

Description

R48−0x30 − Row Noise (R/W)

Bit 15

Frame

−wise Digital

Correction

By default, the row noise is calculated and compensated for

individually for each color of each row. When this bit is set to “1”,

the row noise is calculated and applied for each color of each of

the first two 2 pairs of values and the same values are applied to

each subsequent row, so that new values are calculated and

applied once per frame.

0 N N

Bits

14:12 Gain Threshold

When the upper analog gain bits are equal to or larger than this

threshold, the dark column average is used in the row noise

correction algorithm. Otherwise, the subtracted value is

determined by bit 11. This check is independently performed for

each color, and is a means to turn off the black level algorithm for

lower gains.

0 N N

Bit 11 Use Black

Level Average

0: Use mean of black level programmed threshold in the row

noise correction algorithm for low gains.

1: Use black level frame average from the dark rows in the row

noise correction algorithm for low gains. This frame average

was taken before the last adjustment of the offset DAC for

that frame, so it might be slightly off.

0 N Y

Bit 10 Enable

Correction

0: Normal operation.

1: Enable row noise cancellation algorithm.

When this bit is set, the average value of the dark columns read

out is used as a correction for the whole row. The dark average is

subtracted from each pixel on the row, and then a constant is

added (bits 9:0).

1 N Y

Bits 9:0 Row Noise

Constant

Constant used in the row noise cancellation algorithm. It should be

set to the dark level targeted by the black level algorithm plus the

noise expected between the averaged values of the dark columns.

The default constant is set to

42 LSB.

2A N Y

R89−0x59 − Black Rows (R/W)

Bits 7:0 Black Rows

For each bit set, the corresponding dark row (rows 0–7) are used

in the black level algorithm. For this to occur, the reading of those

rows must be enabled by the settings in R0x22:0.

FF N N

R91−0x5B − Green1 Frame Average (R/O)

Bits 6:0 Green1 Frame

Average

The frame-averaged green1 black level that is used in the black

level calibration algorithm.

R92−0x5C − Blue Frame Average (R/O)

Bits 6:0 Blue Frame

Average

The frame-averaged blue black level that is used in the black level

calibration algorithm.

R93−0x5D − Red Frame Average (R/O)

Bits 6:0 Red Frame

Average

The frame-averaged red black level that is used in the black level

calibration algorithm.

R94−0x5E − Green2 Frame Average (R/O)

Bits 6:0 Green2 Frame

Average

The frame-averaged green2 black level that is used in the black

level calibration algorithm.

R95−0x5F − Threshold (R/W)

Bits 14:8 Upper

Threshold Upper threshold for targeted black level in ADC LSBs. 23 N N

Bits 6:0 Lower

Threshold Lower threshold for targeted black level in ADC LSBs. 1D N N

R96−0x60 − Calibration Control (R/W)

Bit 15 Disable Rapid

Sweep Mode

Disables the rapid sweep mode in the black level algorithm. The

averaging mode remains enabled.

0 Y N

MT9D131

www.onsemi.com

TABLE 5. SENSOR CORE REGISTER DESCRIPTION (continued)

Bit

Field

Bad

Frame

Sync’d to

Frame Start

Default

(Hex)

Description

R96−0x60 − Calibration Control (R/W)

Bit 12 Recalculate

When set to “1”, the rapid sweep mode is triggered if enabled, and

the running frame average is reset to the current frame average.

This bit is write – 1, but always reads back as “0.”

0 Y N

Bit 10 Limit Rapid

Sweep

0: All dark rows can be used for the black level algorithm. This

means that the internal average might not correspond to the

calibration value used for the frame, so the dark row average

should in this case not be used as the starting point for the

digital frame-wise black level algorithm.

1: Dark rows 8–11 are not used for the black level algorithm

controlling the calibration value. Instead, these rows are used

to calculate dark averages that can be a starting point for the

digital frame-wise black level algorithm.

0 N N

Bit 9 Freeze

Calibration

When set to “1”, does not let the averaging mode of the black level

algorithm change the calibration value. Use this with the feature in

the frame-wise black level algorithm that allows you to trigger the

rapid sweep mode when the dark column average gets away from

the black level target.

0 N N

Bit 8 Sweep Mode

When set to “1”, the calibration value is increased by one every

frame, and all channels are the same. This can be used to get a

ramp input to the ADC from the calibration DACs.

0 N N

Bits 7:5 Frames To

Average Over

Two to the power of this value determines how many frames to

average when the black level algorithm is in the averaging mode.

In this mode, the running frame average is calculated from the

following formula:

Running frame ave = old running frame ave – (old running frame

ave)/2n + (new frame ave)/ 2n.

n = frames to average over.

4 N N

Bit 4 Step Size

Forced To 1

When set to “1”, the step size is forced to 1 for the rapid sweep

algorithm. Default operation (0) is to start at a higher step size

when in rapid sweep mode, to converge faster to the correct

value.

0 N N

Bit 3

Switch

Calibration

Values

Reserved. 0

Bit 2 Same Red/Blue When set to “1”, the same calibration value is used for red and

blue pixels: Calib blue = calib red.

0 N Y

Bit 1 Same Green When set to “1”, the same calibration value is used for all green

pixels: Calib green2 = calib green1.

0 N Y

Bit 0 Manual

Override

Manual override of black level correction.

0: Normal operation (default).

1: Override automatic black level correction with programmed

values. (R0x61:0–R0x64:0).

0 N Y

R97−0x61 − Green1 Calibration Value (R/W)

Bits 8:0

Green1

Calibration

Value

Analog calibration offset for green1 pixels, represented as a two’s

complement signed 8-bit value (if bit 8 is clear, the offset is

positive and the magnitude is given by bits 7:0. If bit 8 is set, the

offset is negative and the magnitude is given by not ([7:0]) + 1).

If R0x60:0[0] = 0, this register is R/O and returns the current value

computed by the black level calibration algorithm.

If R0x60:0[0] = 1, this register is R/W and can be used to set the

calibration offset manually. Green1 pixels share rows with red

pixels.

0 N Y

MT9D131

www.onsemi.com

TABLE 5. SENSOR CORE REGISTER DESCRIPTION (continued)

Bit

Field

Bad

Frame

Sync’d to

Frame Start

Default

(Hex)

Description

R98−0x62 − Blue Calibration Value (R/W)

Bits 8:0 Blue Calibration

Value

Analog calibration offset for blue pixels, represented as a two’s

complement signed 8-bit value (if bit 8 is clear, the offset is

positive and the magnitude is given by bits 7:0. If bit 8 is set, the

offset is negative and the magnitude is given by Not ([7:0]) + 1).

If R0x60:0[0] = 0, this register is R/O and returns the current value

computed by the black level calibration algorithm.

If R0x60:0[0] = 1, this register is R/W and can be used to set the

calibration offset manually.

0 N Y

R99−0x63 − Red Calibration Value (R/W)

Bits 8:0 Red Calibration

Value

Analog calibration offset for red pixels, represented as a two’s

complement signed 8-bit value (if bit 8 is clear, the offset is

positive and the magnitude is given by bits 7:0. If bit 8 is set, the

offset is negative and the magnitude is given by Not ([7:0]) + 1).

If R0x60:0[0] = 0, this register is R/O and returns the current value

computed by the black level calibration algorithm.

If R0x60:0[0] = 1, this register is R/W and can be used to manually

set the calibration offset.

0 N Y

R100−0x64 − Green2 Calibration Value (R/W)

Bits 8:0

Green2

Calibration

Value

Analog calibration offset for green2 pixels, represented as a two’s

complement signed 8-bit value (if bit 8 is clear, the offset is

positive and the magnitude is given by bits 7:0. If bit 8 is set, the

offset is negative and the magnitude is given by Not ([7:0]) + 1.)

If R0x60:0[0] = 0, this register is R/O and returns the current value

computed by the black level calibration algorithm.

If R0x60:0[0] = 1, this register is R/W and can be used to manually

set the calibration offset. Green2 pixels share rows with blue

pixels.

0 N Y

R101−0x65 − Clock (R/W)

Bit 15 PLL Bypass 0: Use clock produced by PLL as master clock.

1: Bypass the PLL. Use EXTCLK input signal as master clock.

1 N N

Bit 14 PLL

Power-down

0: PLL powered-up.

1: Keep PLL in power-down to save power (default).

1 N N

Bit 13

Power-down

PLL During

Standby

This register only has an effect when bit 14 = 0.

0: PLL powered-up during standby.

1: Turn off PLL (power-down) during standby to save power

(default).

1 N N

Bit 2 clk_newrow Force clk_newrow to be on continuously. 0 N N

Bit 1 clk_newframe Force clk_newframe to be on continuously. 0 N N

Bit 0 clk_ship Force clk_ship to be on continuously. 0 N N

R102−0x66 − PLL Control 1 (R/W)

Bits 15:8 MM value for PLL must be 16 or higher. 10 N N

Bits 5:0 NN value for PLL. 00 N N

R103−0x67 − PLL Control 2 (R/W)

Bits 11:8 Reserved Do not change from default value.

Bits 6:0 PP value for PLL. 00 N N

R240−0xF0 − Page Register (R/W)

Bits 2:0 Page Register Must be kept at “0” to be able to write/read from sensor. Used in

SOC to access other pages with registers.

0 N N

R241−0xF1 − ByteWise Address (R/W)

Bits 15:0 Bytewise

Address

Special address to perform 16-bit reads and writes to the sensor

in 8-bit chunks. See “8-Bit Write Sequence”.

0 N N

MT9D131

www.onsemi.com

TABLE 5. SENSOR CORE REGISTER DESCRIPTION (continued)

Bit

Field

Bad

Frame

Sync’d to

Frame Start

Default

(Hex)

Description

R242−0xF2 − Context Control (R/W)

Bit 15 Restart

Setting this bit causes the sensor to abandon the current frame

and start resetting the first row. Same physical register as

R0x0D:0[1].

0 N YM

Bit 7 Reserved Reserved. 0 Y N

Bit 3 Read Mode

Select

0: Use read mode context A, R0x21:0.

1: Use read mode context B, R0x20:0.

Bits only found in read mode context B register are always taken

from that register.

1 Y YM

Bit 2 Reserved Reserved. 0 Y Y

Bit 1 Vertical Blank

Select

0: Use vertical blanking context A, R0x08:0.

1: Use vertical blanking context B, R0x06:0.

1 Y YM

Bit 0 Horizontal

Blank Select

0: Use horizontal blanking context A, R0x07:0.

1: Use horizontal blanking context B, R0x05:0.

1 Y YM

R255−0xFF − Reserved (R/O)

Bits 15:0 Reserved Reserved. 1519

1. Unless integration time is less than one frame (R0x0B[13, 0]).

2. f enabled by bit 3 (R0x25[14]).

MT9D131

www.onsemi.com

IFP REGISTERS, PAGE 1

TABLE 6. IFP REGISTERS, PAGE 1

Reg # Bits Default Name

0x08

10:0 0x01F8 Color Pipeline Control

0 0 Toggles the assumption about Bayer CFA (vertical shift).

0: Row containing Blue comes first.

1: Row with Red comes first.

1 0 Toggles the assumption about Bayer CFA (horizontal shift).

0: Green comes first.

1: Red or Blue comes first.

2 0 1: Enables lens shading correction.

3 1 1: Enables on-the-fly defect correction.

4 1 1: Enables 2D aperture correction.

5 1 0: Bypasses color correction (unity color matrix).

1: Enables color correction.

6 1 1: Inverts output pixel clock (in all modes − JPEG, SOC, sensor).

7 1 1: Enables gamma correction.

8 1 1: Enables decimator.

9 0 1: Enables minblank. Allows len generation 2 lines earlier. Also adds 4 pixels to the line size.

10 0 1: Enables 1D aperture correction.

0x09

4:0 0x000A Factory Bypass

1:0 1 Data output bypass. Selects data going to DOUT pads.

00: 10-bit sensor.

01: SOC.

10: JPEG and output FIFO (no bypass). Reg16 and Reg17 (Page 2) have to be set to the

for external 27 MHz clock input, enable it and wait for lock

11: Reserved.

2 0 Reserved.

4:3 1

Reserved.

0x0A

10:0 0x0488 Pad Slew

2:0 0 In bypass mode (R9[1:0] = 2): slew rate for DOUT[7:0], PIXCLK, FRAME_VALID, and

LINE_VALID.

During normal operation, the slew of listed pads is set by JPEG configuration registers. Actual

slew depends on load, temperature, and I/O voltage. Set this register based on customers’

characterization results.

3 1 Unused.

6:4 0 Reserved.

7 0 0: Disable I/O pad input clamp. Set this bit to “1” before going to soft/hard standby to reduce

the leakage current. When coming out of standby, set this bit back to “0.”

1: Enables I/O pad input clamp during standby.That prevents elevated standby current if

pad input floating. The pads are DOUT[7:0], FRAME_VALID, LINE_VALID, PIXCLK.

10:8 4 Slew rate for SDATA. 7 = fastest slew; 0 = slowest. Actual slew depends on load, temperature,

and I/O voltage. Actual slew depends on load, temperature, and I/O voltage. Set this register

based on customers’ characterization results.

MT9D131

www.onsemi.com

TABLE 6. IFP REGISTERS, PAGE 1 (continued)

Reg # NameDefaultBits

0x0B

8:0 0x00DF Internal Clock Control

0 1 Reserved.

1 1 Reserved.

2 1 Reserved.

3 1 1: Enables output FIFO clock.

4 1 1: Enables JPEG clock.

5 0 Reserved.

6 1 Reserved.

7 1 Reserved.

8 0 Reserved.

0x11

10:0 0x0000 X0 Coordinate for Crop Window

Use the crop window for pan and zoom. Crop coordinates are updated synchronously with frame enable, unless freeze

is enabled. In preview mode crop coordinates are automatically divided by X skip factor.

Coordinates are specified as (X0, Y0) and (X1, Y1), where X0 < X1 and Y0 < Y1. Value is overwritten by mode driver

(ID = 7).

0x12

10:0 0x0640 X1 Coordinate for Crop Window +1

See R17:1. Value is overwritten by mode driver (ID = 7).

0x13

10:0 0x0000 Y0 Coordinate for Crop Window

See R17:1. Value is overwritten by mode driver (ID = 7).

0x14

10:0 0x04B0 Y1 Coordinate for Crop Window +1

See R17:1. Value is overwritten by mode driver (ID = 7).

0x15

13:0 0x0000 Decimator Control

0 0 Reserved.

1 0 Reserved.

2 0 High precision mode. Additional bits for result are stored. Can only be used for decimation > 2.

3 0 Reserved.

4 0 Enables 4:2:0 mode.

5:6 0 Reserved.

This register controls operation of the decimator. Value is overwritten by mode driver (ID = 7).

0x16

12:0 0x0800 Weight for Horizontal Decimation

X output = int (X input/2048 * reg. value). Value is calculated and overwritten by mode driver

(ID = 7).

0x17

12:0 0x0800 Weight for Vertical Decimation

Y output = int (Y input/2048*reg. value). Value is calculated and overwritten by mode driver

(ID = 7).

Input size is defined by Registers 17–20. Minimal output size supported by the decimator is 3 x 1 pixel.

0x20

15:0 0xC814 Luminance Range of Pixels Considered in WB Statistics

7:0 20 Lower limit of luminance for WB statistics.

15:8 200 Upper limit of luminance for WB statistics.

To avoid skewing WB statistics by very dark or very bright values, this register allows programming the luminance range

of pixels to be used for WB computation.

MT9D131

www.onsemi.com

TABLE 6. IFP REGISTERS, PAGE 1 (continued)

Reg # NameDefaultBits

0x2D

15:0 0x5000 Right/Left Coordinates of AWB Measurement Window

7:0 0 Left window boundary.

15:8 80 Right window boundary.

This register specifies the right/left coordinates of the window used by AWB measurement engine. The values

programmed in the registers are desired boundaries divided by 8.

0x2E

15:0 0x3C00 Bottom/Top Coordinates of AWB Measurement Window

7:0 0 Top window boundary.

15:8 60 Bottom window boundary.

This register specifies the bottom/top coordinates of the window used by AWB measurement engine. The values

programmed in the registers are desired boundaries divided by 8.

0x30

7:0 R/O Red Chrominance Measure Calculated by AWB

This register contains a measure of red chrominance obtained using AWB measurement algorithm. The measure is

normalized to an arbitrary maximum value; the same for R48:1, R49:1, and R50:1. Because of this normalization, only

the ratios of values of registers R48:1 R49:1, and R50:1 should be used.

0x31

7:0 R/O Luminance Measure Calculated by AWB

This register contains a measure of image luminance obtained using AWB measurement algorithm. The measure is

normalized to an arbitrary maximum value; the same for R48:1, R49:1, and R50:1. Because of this normalization, only

the ratios of values of registers R48:1, R49:1, and R50:1 should be used.

0x32

7:0 R/O Blue Chrominance Measure Calculated by AWB

This register contains a measure of blue chrominance obtained using AWB measurement algorithm. The measure is

normalized to an arbitrary maximum value; the same for R48:1, R49:1, and R50:1. Because of this normalization, only

the ratios of values of registers R48:1, R49:1, and R50:1 should be used.

0x35

15:0 0x1208 1D Aperture Correction Parameters

7:0 8 Ap_knee; threshold for aperture signal.

10:8 2 Ap_gain; gain for aperture signal.

13:11 2 Ap_exp; exponent for gain for aperture signal.

0x36

15:0 0x1208 2D Aperture Correction Parameters

7:0 8 Ap_knee; threshold for aperture signal.

10:8 2 Ap_gain; gain for aperture signal.

13:11 2 Ap_exp; exponent for gain for aperture signal.

14 0 Reserved.

Defines 2D aperture gain and threshold.

0x37

7:0 0x080 Filters

2:0 0 UV filter:

000: No filter

001: 11110 averaging filter

010: 01100 averaging filter

011: 01210 averaging filter

100: 12221 averaging filter

101: Median 3

110: Median 5

111: Reserved

MT9D131

www.onsemi.com

TABLE 6. IFP REGISTERS, PAGE 1 (continued)

Reg # NameDefaultBits

0x37

4:3 0 Y filter mode:

00: No filter

01: Median 3

10: Median 5

11: Reserved

5 0 Permanently enables Y filter.

0x3B

9:0 0 Second Black Level

This register contains the value subtracted by IFP from pixel values prior to CCM. If the subtraction produces a negative

result for a particular pixel, the value of this pixel is set to “0”

0x3C

9:0 42 First Black Level

This register contains the value subtracted by IFP from raw pixel values before applying lens shading correction and

digital gains. If the subtraction produces a negative result for a particular pixel, the value of this pixel is set to “0”.

Typically, the subtracted value should be equal to the black level targeted by the sensor. This value is subtracted from

all test patterns as well.

0x43

0 1 Enable Support for Preview Modes

1: Enables automatic recalculation operation of coefficient lens correction dependent on sensor output resolution.

0x44

15:0 N/A Mirrors Sensor Register 0x20

Read only

0x45

15:0 N/A Mirrors Sensor Register 0xF2

Read only

0x46

15:0 N/A Mirrors Sensor Register 0x21

Read only

0x47

7:0 16 Edge Threshold for Interpolation

Threshold for identifying pixel neighborhood as having an edge.

0x48

2:0 0 Test Pattern

2:0 0 Test mode.

001: Flat field; RGB values are specified in R73−75:1

010: Vertical monochrome ramp

011: Vertical color bars

100: Vertical monochrome bars; set bar intensity in R73:1 and R74:1

101: Pseudo-random test pattern

110: Horizontal monochrome bars; set bar intensity in R73:1 and R74:1

Injects test pattern into beginning of color pipeline.

0x49

9:0 256 Test Pattern R/Monochrome Value

0x4A

9:0 256 Test Pattern G/Monochrome Value

0x4B

9:0 256 Test Pattern B Value

0x4E

7:0 32 Digital Gain 2

Default setting 32 corresponds to gain value of 1. Gain scales linearly with value.

0x60

14:0 0x2923 Color Correction Matrix Exponents for C11...C22

2:0: Matrix element 1 (C11) exponent

5:3: Matrix element 2 (C12) exponent

8:6: Matrix element 3 (C13) exponent

11:9: Matrix element 4 (C21) exponent

14:12: Matrix element 5 (C22) exponent

MT9D131

www.onsemi.com

TABLE 6. IFP REGISTERS, PAGE 1 (continued)

Reg # NameDefaultBits

0x61

11:0 0x0524 Color Correction Matrix Exponents for C22...C33

2:0: Matrix element 6 (C23) exponent

5:3: Matrix element 7(C31) exponent

8:6: matrix element 8(C32) exponent

11:9: Matrix element 9(C33) exponent

The value of a matrix coefficient is calculated

Cij = (1 − 2*Sij)*Mij*2^−(Eij + 4), 0< = Eij < = 4

Where Sij is coefficient’s sign, Mij is the mantissa, and Eij is the exponent.

0x62

15:0 0xBBC8 Color Correction Matrix Elements 1 and 2 Mantissas

7:0 200 Color correction matrix element 1 (C11).

15:8 187 Color correction matrix element 2 (C12).

0x63

15:0 0xCA3A Color Correction Matrix Elements 3 and 4 Mantissas

7:0 58 Color correction matrix element 3 (C13).

15:8 202 Color correction matrix element 4 (C21).

100

0x64

15:0 0x3B85 Color Correction Matrix Elements 5 and 6 Mantissas

7:0 133 Color correction matrix element 5 (C22).

15:8 59 Color correction matrix element 6 (C23).

101

0x65

15:0 0xF26F Color Correction Matrix Elements 7 and 8 Mantissas

7:0 111 Color correction matrix element 7 (C31).

15:8 242 Color correction matrix element 8 (C32).

102

0x66

13:0 0x3D9C Color Correction Matrix Element 9 Mantissa and Signs

7:0 156 Color correction matrix element 9 (C33).

13:8 61 Signs for off-diagonal CCM elements.

Bit 8: sign for C12

Bit 9: sign for C13

Bit 10: sign for C21

Bit 11: sign for C23

Bit 12: sign for C31

Bit 13: sign for C32

1: indicates negative

0: indicates positive

Signs for C11, C22, and C33 are assumed always positive.

106

0x6A

9:0 128 Digital Gain 1 for Red Pixels

Default setting 128 corresponds to gain value of 1. Gain scales linearly with value.

107

0x6B

9:0 128 Digital Gain 1 for Green1 Pixels

Default setting 128 corresponds to gain value of 1. Gain scales linearly with value.

108

0x6C

9:0 128 Digital Gain 1 for Green2 Pixels

Default setting 128 corresponds to gain value of 1. Gain scales linearly with value.

109

0x6D

9:0 128 Digital Gain 1 for Blue Pixels

Default setting 128 corresponds to gain value of 1. Gain scales linearly with value.

110

0x6E

9:0 128 Digital Gain 1 for All Colors

Write 128 to set all gains (R106−R109) to 1. When read, this register returns the value of R107.

122

0x7A

15:0 80 Boundaries of Flicker Measurement Window (Left/Width)

7:0 80 Window width.

15:8 0 Left window boundary.

This register specifies the boundaries of the window used by the flicker measurement engine. The values programmed

in the registers are the desired boundaries divided by 8.

MT9D131

www.onsemi.com

TABLE 6. IFP REGISTERS, PAGE 1 (continued)

Reg # NameDefaultBits

123

0x7B

15:0 0x0088 Boundaries of Flicker Measurement Window (Top/Height)

5:0 8 Window height.

15:6 2 Top window boundary.

This register specifies the boundaries of the window used by the flicker measurement engine.

124

0x7C

15:0 5120 Flicker Measurement Window Size

This register specifies the number of pixels in the window used by the flicker measurement engine.

125

0x7D

15:0 R/O Measure of Average Luminance in Flicker Measurement Window

150

0x96

0 0 Blank Frames

0 0 0: When bit is unset, output resumes with the next frame. The bit is synchronized with

frame enable. See freeze bit (R152[7])1: Blank outgoing frames.

1: When bit is set, current frame completes and following frames are not output,

FEN = LEN = 0.

151

0x97

7:0 0 Output Format Configuration

0 0 In YUV output mode, swaps Cb and Cr channels. In RGB mode, swaps R and B. This bit is

subject to synchronous update.

1 0 Swaps chrominance byte with luminance byte in YUV output. In RGB mode, swaps odd and

even bytes. This bit is subject to synchronous update.

2 0 Reserved.

3 0 Monochrome output.

4 0 1: Uses ITU−R BT.601 codes when bypassing FIFO.

(0xAB = frame start; 0x80 = line start; 0x9D = line end; 0xB6 = frame end.)

5 0 0: Output YUV

1: Output RGB

7:6 0 RGB output format:

00: 16-bit RGB565

01: 15-bit RGB555

10: 12-bit RGB444x

11: 12-bit RGBx444

MT9D131

www.onsemi.com

TABLE 6. IFP REGISTERS, PAGE 1 (continued)

Reg # NameDefaultBits

152

0x98

2:0 0 Output Format Test

0 0 1: Disables Cr channel (R in RGB mode).

1 0 1: Disables Y channel (G in RGB mode).

2 0 1: Disables Cb channel (B in RGB mode).

5:3 0 Test ramp output:

00: Off

01: By column

10: By row

11: By frame

6 0 1: Enables 8+2 bypass.

7 0 1: Freezes update of SOC registers affecting output size and format.

These include R151:1, R17−23:1.

153

0x99

11:0 R/O Line Count

154

0x9A

15:0 R/O Frame Count

164

0xA4

15:0 0x6440 Special Effects

2:0 0 Special effect selection bits:

0: Disabled

1: Monochrome

2: Sepia

3: Negative

4: Solarization with unmodified UV

5: Solarization with −UV

5:3 0 Dither enable and amplitude. Valid values are 1...4, others disable.

6 1 1: Dithers only in luma channel, 0: dither in all color channels.

15:8 0 Solarization threshold for luma, divided by 2; 64...127.

165

0xA5

15:0 0xB023 Sepia Constants

7:0 35 Sepia constant for Cr.

15:8 176 Sepia constant for Cb.

178

0xB2

15:0 0x2700 Gamma Curve Knees 0 and 1

7:0 Ordinate of gamma curve knee point 0 (its abscissa is 0).

15:8 Gamma curve knee point 1.

Gamma correction curve is implemented in the MT9D131 as a piecewise linear function mapping 12-bit arguments to

8-bit output. Seventeen line fragments forming the curve connect 19 knee points, whose abscissas are fixed and

ordinates are programmable through registers R[178:187]:1. The abscissas of the knee points are 0, 64, 128, 256, 512,

768, 1024, 1280, 1536, 1792, 2048, 2304, 2560, 2816, 3072, 3328, 3584, 3840, and 4095. Ordinates of knee points

written directly to the registers R[178:187]:1 may be overwritten by mode driver (ID = 7). The recommended way to

program a gamma curve into the MT9D131 is to write desired knee ordinates to one of the two mode.gamma_table

[A/B][] arrays that hold gamma curves used in contexts A and B. Once the desired ordinates are in one of those arrays,

all that is needed to put them into effect (that is, into the registers) is a short command telling the sequencer to go to

proper context or through REFRESH loop.

179

0xB3

15:0 0x4936 Gamma Curve Knees 2 and 3

7:0 Gamma curve knee point 2.

15:8 Gamma curve knee point 3.

180

0xB4

15:0 0x7864 Gamma Curve Knees 4 and 5

7:0 Gamma curve knee point 4.

15:8 Gamma curve knee point 5.

MT9D131

www.onsemi.com

TABLE 6. IFP REGISTERS, PAGE 1 (continued)

Reg # NameDefaultBits

181

0xB5

15:0 0x9789 Gamma Curve Knees 6 and 7

7:0 Gamma curve knee point 6.

15:8 Gamma curve knee point 7.

182

0xB6

15:0 0xB0A4 Gamma Curve Knees 8 and 9

7:0 Gamma curve knee point 8.

15:8 Gamma curve knee point 9.

183

0xB7

15:0 0xC5BB Gamma Curve Knees 10 and 11

7:0 Gamma curve knee point 10.

15:8 Gamma curve knee point 11.

184

0xB8

15:0 0xD7CE Gamma Curve Knees 12 and 13

7:0 Gamma curve knee point 12.

15:8 Gamma curve knee point 13.

185

0xB9

15:0 0xE8E0 Gamma Curve Knees 14 and 15

7:0 Gamma curve knee point 14.

15:8 Gamma curve knee point 15.

186

0xBA

15:0 0xF8F0 Gamma Curve Knees 16 and 17

7:0 Gamma curve knee point 16.

15:8 Gamma curve knee point 17.

187

0xBB

7:0 0x00FF Gamma Curve Knee 18

190

0xBE

3:0 6 YUV/YCbCr control

3 0 Clips Y values to 16–235; clips UV values to 16–240.

2 1 Adds 128 to U and V values.

1 1 0: Uses sRGB coefficients.

1: ITU-R BT.601 coefficients

0 0 0: No scaling

1: Scales Y data by 219/256 and UV data by 224/256.

191

0xBF

15:0 0 Y/RGB Offset

15:8 0 Y offset.

7:0 0 RGB offset.

195

0xC3

15:0 0 Microcontroller Boot Mode

0 0 1: Reset microcontroller.

1,2,3,6:4,

6:5,7:5

0 Reserved.

7 0 Microcontroller debug indicator.

11:8,12,1

3,14,15

R/O Reserved.

MT9D131

www.onsemi.com

TABLE 6. IFP REGISTERS, PAGE 1 (continued)

Reg # NameDefaultBits

198

0xC6

15:0 0 Microcontroller Variable Address

7:0 0 Bits 7:0 of address for physical access; driver variable offset for logical access.

12:8 0 Bits 12:8 of address for physical access; driver ID for logical access.

14:13 0 Bits 14:13 of address for physical access; R0xC6:1[14:13] = 01 select logical access.

15 0 0: 16-bit

1: 8-bit access

Microcontroller variables are similar to two-wire serial interface registers, except that they are located in the

microcontroller’s memory and have different bit widths. Registers 198:1 and R200:1 provide easy access to variables

that can be represented as 8- or 16-bit unsigned integers (bytes or words). To access such a variable, one must write its

address to R0xC6:1 and then read its value from R200:1 or write a new value to the same register. Variables having

more than 16 bits (for example 32-bit unsigned long integers) must be accessed as arrays of bytes or words − there is

no way to read or write their values without parsing. Variable address written to R0xC6:1 can be physical or logical.

Physical address is the actual address of a byte or word in the microcontroller’s address space. The logical addressing

option is provided only to facilitate access to public variables of various firmware drivers. Logical address of a public

variable consists of a 5-bit driver ID 1 = sequencer, and so on) and 8-bit offset of the variable in the driver’s data

structure (which cannot be larger than 256 bytes).

200

0xC8

15:0 0 Microcontroller Variable Data

To read current value of an 8- or 16-bit variable from microcontroller memory, write its address to R0xC6:1 and read

R200:1. To change value of a variable, write its address to R0xC6:1 and its new value to R200:1. When bit width of a

variable is specified as 8 bits (R0xC6:1[15] = 1), the upper byte of R200:1 is irrelevant. It is set to “0” when the register

is read and ignored when it is written to. See R0xC6:1 above for explanation how to read and set variables having more

than 16 bits.

201−209

0xC9−D1

15:0 0 Microcontroller Variable Data using Burst Two-Wire Serial Interface Access

Use these registers to read or write up to 16 bytes of variable data using the burst two-wire serial interface access

mode. The variables must have consecutive addresses.

240

0xF0

2:0 1 Page Register

0: Sensor core

1: IFP page 1

2: IFP page 2

241

0xF1

15:0 0 Bytewise Address

Special address to perform 16−bit READs and WRITEs to the sensor in 8-bit chunks. See “8-Bit

Write Sequence”.

MT9D131

www.onsemi.com

TABLE 7. IFP REGISTERS, PAGE 2

Reg # Bits Default Name

0x00

15:0 0 JPEG Control Register

0 0 Start/Enable Encoder: Enable JPEG encoding at the start of next frame.

1 0 Test SRAM: When set, allows host or microcontroller to take control of the output FIFO buffer

and the sixteen 800 x 16 RAMs in the re-order buffer for testing. Used in conjunction with JPEG

RAM test controls register to simultaneously write all 17 RAMs and individually read each RAM.

[14:2] Return zero when read.

15 0 Soft Reset.

0x02

15:0 0 JPEG Status Register 0

0 0 Transfer done status flag. When bit is set to “1”, it indicates that the completion of transfer of the

JPEG-compressed image. This status flag remains set until cleared by the host or

microcontroller by writing “1” to bit [0]. Subsequently, the output FIFO overflow, the spoof

oversize error and the re-order buffer error status bits are reset. The output buffer clock must be

present to clear this bit.

1 0 Output FIFO overflow status flag. When bit is set to “1”, it indicates that an overflow condition

was detected in the output FIFO during the frame transfer and that transfer was terminated

prematurely. This status flag remains set until cleared by the host or microcontroller as it clears

transfer done flag. Valid for JPEG compressed images only.

2 0 Spoof oversize error status flag. When bit is set to “1”, it indicates that the spoof frame size is

too small for JPEG data stream. This status flag remains set until cleared by the host or

microcontroller as it clears transfer done flag. Valid for JPEG compressed images only.

3 0 Re-order buffer error status flag: When the re-order buffer detects an overflow or underflow

condition, this bit is set to “1.” This bit is cleared by writing a “1” to bit[0] of this register.

5:4 0 Watermark of the output FIFO.

00: Less than 25% full

01: 25% to less than 50% full

10: 50% to less than 75% full

11: 75% full or more

Watermark is cleared when the host or microcontroller writes “1” to bit 4 of this register (R258).

7:6 0 QTable_ID.

00: Quantization table set 0

01: Quantization table set 1

10: Quantization table set 2

11: Reserved

15:8 0 JPEG data length bits 23:16. Highest byte of 24-bit JPEG data length.

0x03

15:0 0 JPEG Status Register 1 − JPEG Data Length Bits 15:0

This register combined with R2:2[15:8] gives the total number of data bytes successfully encoded−a 24-bit JPEG data

length. If an output FIFO overflow occurs, this register holds the total number of data bytes already sent out by the

JPEG encoder (up to the point where the overflow occurs).

0x04

2:0 0 JPEG Status Register 2 − Output FIFO Fullness Status

Instantaneous FIFO fullness status code:

000: FIFO is empty

001: 0% < fullness < 25%

011: 25% < = fullness < 50%

010: 50% < = fullness < 75%

110: 75% < = fullness < = 100%

MT9D131

www.onsemi.com

TABLE 7. IFP REGISTERS, PAGE 2 (continued)

Reg # NameDefaultBits

0x05

5:0 0 JPEG Front End Configuration Register

1 0 JPEG monochrome mode. When this bit is set, the re-order buffer control sends only luma data

to the JPEG encoder.

0 0 Color component composition:

0: 4:2:2 format

1: 4:2:0 format

0x06

0:0 0 JPEG Core Configuration Register − Extend JPEG Quantization Matrix

Presently, the JPEG encoder core supports two sets of quantization tables. (Each set contains a pair of quantization

tables - one for luma, one for chroma.) The quantization memory available allows an additional set of quantization

tables to be stored. By setting this bit to “1”, the encoder uses the third table pair. If the bit is set to “0”, then whichever

set of tables 1 and 2 was programmed will be used.

0x0A

0:0 1 JPEG Encoder Bypass

Set bit 0 to “1” of this register to have uncompressed frames from the SOC captured in the output FIFO and transferred

out as spoof frames (JPEG encoder is bypassed). Register 13, bit 0, should be set to “1” for spoof-mode output. When

the bit is cleared (set to “0”), JPEG-encoded frames are transferred out through the FIFO.

0x0D

10:0 0x0007 Output Configuration Register

0 1 Enable spoof frame: When this bit is set to “1”, the data captured in the output FIFO is sent out

as a spoofed frame, formatted according to information stored in the various spoof registers.

This output mode can be used to output both JPEG-compressed and uncompressed image

data. JPEG data may be padded if dummy data is needed. During LINE_VALID assertion

period, the output clock is only clocked when there is valid JPEG data or padded dummy data

to be transmitted. This may result in a non-uniform clock period. When LINE_VALID is

de-asserted, the output clock is enabled according to SPOOF_LV_LEAD and

SPOOF_LV_TRAIL setting. JPEG SOI/EOI markers cannot be inserted into spoof frames.

1 1 Enable output pixel clock between frames: When this bit is set to “1”, this bit enables the pixel

clock to run whether FRAME_VALID is LOW or HIGH. Clearing the bit disables the clock during

the periods when FRAME_VALID is de-asserted except for SOI/EOI markers transmission if

they are outside the FV assertion period. The gating off of this output pixel clock saves power.

2 1 Enable pixel clock during invalid data: When this bit is set to “1”, the pixel clock runs

continuously while FRAME_VALID is asserted but LINE_VALID is de-asserted. When cleared, it

causes the pixel clock to be active only when valid JPEG data are output. Disabling pixel clock

during LINE_VALID de-assertion is not support in spoof frame.

3 0 Enable SOI/EOI insertion: When this bit is set to “1”, this bit causes SOI and EOI markers to be

output at the beginning and end of every JPEG-encoded frame. When the bit is cleared, only

JPEG data bytes are output.

4 0 Insert SOI and EOI when FRAME_VALID is HIGH: When this bit is set to “1”, SOI and EOI are

inside FV assertion period. When it is”0,” SOI, and EOI are outside FRAME_VALID assertion

period. This bit is relevant only when SOI/EOI insertion is enabled.

5 0 Ignore spoof frame height: This bit is used in conjunction with bit 0 that enables spoof framing.

When this bit is set to “1”, the JPEG unit output section ignores the spoof frame height register.

The spoof frame ends when either JPEG bytes or uncompressed image data are exhausted.

Both kinds of data are always padded with dummy data to the programmed spoof frame width.

6 0 Enable variable pixel clock rate: When this bit is set to “1”, it enables the adaptive pixel clock

frequency feature. The pixel clock is switched from PCLK1 to PCLK2 to PCLK3, depending on

the output FIFO fullness. When fullness reaches 50%, the pixel clock is switched from PCLK1

to PCLK2. When the fullness reaches 75%, the clock is switched to PCLK3. As the FIFO

fullness drops below 50%, PIXCLK switches from PCLK3 to PCLK2; as it drops below 25%, it

switches back to PCLK1. At the start of a frame, it always starts with PCLK1.

7 0 Enable byte swap: Toggling this bit swaps the even and odd bytes in JPEG data stream. Byte

swapping supported only when enable spoof frame is set.

8 0 Duplicate FRAME_VALID on LINE_VALID: When this bit is set to “1”, the FRAME_VALID

waveform is output on LINE_VALID output also; therefore, the two are identical.

9 0 Enable status insertion: When this bit is set to “1”, the JPEG module appends the status byte to

the end of the JPEG byte stream. This register should only be set when transferring in

continuous mode. The status byte inserted at the end of the JPEG byte stream is Reg2 bit [7:0].

MT9D131

www.onsemi.com

TABLE 7. IFP REGISTERS, PAGE 2 (continued)

Reg # NameDefaultBits

0x0D

10:0 0x0007 Output Configuration Register

10 0 Enable spoof ITU-R BT.601 codes: This bit is relevant matters when uncompressed frames are

output in the spoof mode. When this bit is set to “1”, the bit causes the ITU-R BT.601 markers

SOF, EOF, SOL, EOL to be inserted into every frame. Codes are:

Start of Frame: FF0000AB

End of Frame: FF0000B6

Start of Line: FF000080

End of Line: FF00009D

11 0Freeze_update; Default = 0.

When this bit is set to “1”, it disables the transfer of values from registers 0x0A, 0x0D (except

freeze_update), 0x0E, 0x0F, 0x10, 0x11, 0x12 into their corresponding shadow registers. When

cleared, the shadow registers are updated with values from their corresponding configuration

registers at the end of vertical blanking of the input image. The shadow registers allow the

microcontroller to change configuration registers values during the active frame time without

corrupting the current frame transfer.

0x0E

15:0 0x0501 Output PCLK1 & PCLK2 Configuration Register

3:0 0x1 Output clock frequency divisor N1: This 4-bit register contains an integer divisor used to divide

master clock frequency to obtain the frequency of output clock source PCLK1. A value of “0” in

this register has the same effect as “1.”

7:5 0 PCLK1 slew rate: The value contained in this 3-bit register determines the slew rate of the

output clock when PCLK1 is selected as its source.

11:8 0x5 Output Clock Frequency Divisor N2: This 4-bit register contains an integer divisor used to divide

master clock frequency to obtain the frequency of output clock source PCLK2. The output clock

switches from PCLK1 to PCLK2 when the output buffer fullness reaches 50%. A value of “0” in

this register has the same effect as “1.”

12 0 Not used.

15:13 0 PCLK2 slew rate: The value contained in this 3-bit register determines the slew rate of the

output clock when PCLK2 is selected as its source.

0x0F

7:0 0x0003 Output PCLK3 Configuration Register

3:0 0x03 Output clock frequency divisor N3: This 4-bit register contains an integer divisor used to divide

master clock frequency to obtain the frequency of output clock source PCLK3. The output clock

switches from PCLK2 to PCLK3 when the output buffer fullness reaches 75 %. A value of “0” in

this register has the same effect as 1.

4 0 Not used.

7:5 0 PCLK3 slew rate: The value contained in this 3-bit register determines the slew rate of the

output clock when PCLK3 is selected as its source.

0x10

11:0 0x0640 Spoof Frame Width

This register defines the width of the spoof frame used to output data captured in the output FIFO. It corresponds to the

real time assertion of LINE_VALID in terms of number of PIXCLKs. It must be an even number.

0x11

11:0 0x0258 Spoof Frame Height

This register defines the height of the spoof frame used to output data captured in the output FIFO. The height is equal

to the number of assertions of LINE_VALID within one assertion of FRAME_VALID. The value stored in this register is

ignored if bit R13:2[5] is set.

0x12

15:0 0x0606 Spoof Frame Line Timing

7:0 0x6 Spoof LINE_VALID lead. The number of clocks before LINE_VALID is asserted in a spoof

frame. This must be a minimum value of “5.”

15:8 0x6 Spoof LINE_VALID trail. The number of clocks after LINE_VALID is de-asserted in a spoof

frame. This must be a minimum value of “5.”

0x1D

15:0 0 JPEG RAM Test Control Register

9:0 0 Tested SRAM address: This register defines the location in the seventeen 800 x 16 RAMs that

is being accessed by the host or microcontroller while testing the group of SRAMs. A specified

16-bit location can be selected from 0 through 799. The address is automatically incremented

when R31:2 is written during SRAM test data WRITE or READ during SRAM test data READ.

MT9D131

www.onsemi.com

TABLE 7. IFP REGISTERS, PAGE 2 (continued)

Reg # NameDefaultBits

0x1D

15:0 0 JPEG RAM Test Control Register

12:110 0 Test Y/C SRAM Register: Address the same set of 8 SRAMs (either for Y or for C), this register

setting identifies which of the 8 SRAMs is selected. 000 for SRAM1, 001 for SRAM2, 0, 111 for

SRAM8.

13 0 Test Y/C SRAM Select Register: Select a bank of 8 SRAMs from luminance or from

chrominance. Y = 1, C = 0.

14 0 Test output buffer SRAM: Select to read output buffer SRAM and supersedes Y/C SRAMs. If

this bit is set to “1”, data from the output buffer RAM is selected to be read. During data WRITE,

this has no effect.

15 0 SRAM write enable. This bit is used in conjunction with the RAM selection register. When this

bit is set to “1”, the RAM specified in the selection register undergoes a test write cycle. Data

residing in the indirect data register R31:2 is loaded into all seventeen 800 x 16 SRAMS

simultaneously. Resetting the bit to “0”, thereafter causes a test READ cycle to be performed

and the data is read from the SRAMs and loaded back into R31:2. This bit is write_enable when

1; read_enable when 0. The READ and WRITE cycles occur when R31:2 is accessed.

0x1E

15:0 0 JPEG Indirect Access Control Register

10:0 0 Indirect access address register: This 11-bit register contains the address of the register or

memory to be accessed indirectly.

12:11 0 Unused.

13 0 Enable two-wire serial interface burst: When this bit is set to “1”, the two-wire serial interface

decoder operates in burst mode for the indirect data register (READ burst and WRITE burst).

The longest burst supported is 16 (128 READ or WRITE cycles).

14 0 Enable indirect writing: When this bit is set to “1”, data from the indirect data register is written

to the Indirect address location specified by [10:0] of this register except when auto-increment

is set. Reading the same address location when this bit is reset to “0.”

15 0 Address auto-increment: When this bit is set to “1”, the value in the indirect access address

data register. This feature is used to emulate a burst access to memory or registers being

accessed indirectly.

0x1F

15:0 0 JPEG Indirect Access Data Register

Writing to, and reading from this register, is equivalent to performing these operations on registers or memory being

indirectly accessed. When address auto-increment bit is set in JPEG indirect access control register, multiple writes or

reads from this register affect a burst data transfer. Data is written to or read from indirect registers (when TestSRAM

REG 0x0[1] is set to “0”), or the 800 x 16 SRAMs (when TestSRAM is set to “1”).

32−46

0x20−0x2E

15:0 0 JPEG Indirect Access Data Register

Same as R31:2 when doing two-wire serial interface burst.

128

0x80

10:0 0x0160 Lens Correction Control

0 0 Sign for the K*F(x)*F(y). If 0, then K is positive; if 1, then K is negative.

1 0 When this bit is set to “1”, all the second X derivatives are doubled.

2 0 When this bit is set to “1”, all the second Y derivatives are doubled.

3:5 100 Divisor for the first derivative, X direction. 000−/1, 001−/2, 010−/4, ... 111−/128. Also applies to

second derivative.

6:8 101 Divisor for the first derivative, Y direction. 000−/1, 001−/2, 010−/4, ... 111−/128. Also applies to

second derivative.

9 0 Shift column, LC specific.

10 0 Shift row, LC specific.

This register controls behavior of lens correction.

129

0x81

15:0 0x6432 Zone Boundaries X1 and X2

7:0 X2 boundary (/4) position.

15:8 X1 boundary (/4) position.

Definition of X1 and X2 boundaries

MT9D131

www.onsemi.com

TABLE 7. IFP REGISTERS, PAGE 2 (continued)

Reg # NameDefaultBits

130

0x82

15:0 0x3296 Zone Boundaries X0 and X3

7:0 X0 boundary (/4) position.

15:8 X3 boundary (/4) position.

Definition of X0 and X3 boundaries.

131

0x83

15:0 0x9664 Zone Boundaries X4 and X5

7:0 X4 boundary (/4) position.

15:8 X5 boundary (/4) position.

Definition of X4 and X5 boundaries.

132

0x84

15:0 0x5028 Zone Boundaries Y1 and Y2

7:0 Y2 boundary (/4) position.

15:8 Y1 boundary (/4) position.

Definition of Y1 and Y2 boundaries.

133

0x85

15:0 0x2878 Zone Boundaries Y0 and Y3

7:0 Y0 boundary (/4) position.

15:8 Y3 boundary (/4) position.

Definition of Y0 and Y3 boundaries.

134

0x86

15:0 0x7850 Zone Boundaries Y4 and Y5

7:0 Y4 boundary (/4) position.

15:8 Y5 boundary (/4) position.

Definition of Y4 and Y5 boundaries.

135

0x87

15:0 0x0000 Center Offset

7:0 Offset of LC center in respect to geometrical center. X coordinate(/4).

15:8 Offset of LC center in respect to geometrical center. Ycoordinate(/4).

Offset of the central point for the lens correction (relative to the center of imaging array).

136

0x88

11:0 0x015E F(x) for Red Color at the First Pixel of the Array

137

0x89

11:0 0x0143 F(x) for Green Color at the First Pixel of the Array

138

0x8A

11:0 0x0127 F(x) for Blue Color at the First Pixel of the Array

139

0x8B

11:0 0x012C F(y) for Red Color at the First Pixel of the Array

140

0x8C

11:0 0x0103 F(y) for Green Color at the First Pixel of the Array

141

0x8D

11:0 0x00FD F(y) for Blue Color at the First Pixel of the Array

142

0x8E

11:0 0x0CEF dF/dx for Red Color at the First Pixel of the Array

143

0x8F

11:0 0x0D38 dF/dx for Green Color at the First Pixel of the Array

144

0x90

11:0 0x0D92 dF/dx for Blue Color at the First Pixel of the Array

145

0x91

11:0 0x0C18 dF/dy for Red Color at the First Pixel of the Array

MT9D131

www.onsemi.com

TABLE 7. IFP REGISTERS, PAGE 2 (continued)

Reg # NameDefaultBits

146

0x92

11:0 0x0CF1 dF/dy for Green Color at the First Pixel of the Array

147

0x93

11:0 0x0D05 dF/dy for Blue Color at the First Pixel of the Array

148

0x94

15:0 0x0B03 Second Derivative for Zone 0 Red Color

7:0 d2F/dx2 for zone 0 red color.

15:8 d2F/dy2 for zone 0 red color.

Second derivative for red color in zone 0.

149

0x95

15:0 0x0000 Second Derivative for Zone 0 Green Color

7:0 d2F/dx2 for zone 0 green color.

15:8 d2F/dy2 for zone 0 green color.

Second derivative for green color in zone 0.

150

0x96

15:0 0x0100 Second Derivative for Zone 0 Blue Color

7:0 d2F/dx2 for zone 0 blue color.

15:8 d2F/dy2 for zone 0 blue color.

Second derivative for green color in zone 0.

151

0x97

15:0 0x2534 Second Derivative for Zone 1 Red Color

7:0 d2F/dx2 for zone 1 red color.

15:8 d2F/dy2 for zone 1 red color.

Second derivative for red color in zone 1.

152

0x98

15:0 0x1C33 Second Derivative for Zone 1 Green Color

7:0 d2F/dx2 for zone 1 green color.

15:8 d2F/dy2 for zone 1 green color.

Second derivative for green color in zone 1.

153

0x99

15:0 0x1A2E Second Derivative for Zone 1 Blue Color

7:0 d2F/dx2 for zone 1 blue color.

15:8 d2F/dy2 for zone 1 blue color.

Second derivative for green color in zone 1.

154

0x9A

15:0 0x2A3A Second Derivative for Zone 2 Red color

7:0 d2F/dx2 for zone 2 red color.

15:8 d2F/dy2 for zone 2 red color.

Second derivative for red color in zone 2.

155

0x9B

15:0 0x252D Second Derivative for Zone 2 Green Color

7:0 d2F/dx2 for zone 2 green color.

15:8 d2F/dy2 for zone 2 green color.

Second derivative for green color in zone 2.

156

0x9C

15:0 0x2823 Second Derivative for Zone 2 Blue Color

7:0 d2F/dx2 for zone 2 blue color.

15:8 d2F/dy2 for zone 2 blue color.

Second derivative for green color in zone 2.

157

0x9D

15:0 0x0F14 Second Derivative for Zone 3 Red Color

7:0 d2F/dx2 for zone 3 red color.

MT9D131

www.onsemi.com

TABLE 7. IFP REGISTERS, PAGE 2 (continued)

Reg # NameDefaultBits

15:8 d2F/dy2 for zone 3 red color.

Second derivative for red color in zone 3.

158

0x9E

15:0 0x0D20 Second Derivative for Zone 3 Green Color

7:0 d2F/dx2 for zone 3 green color.

15:8 d2F/dy2 for zone 3 green color.

Second derivative for green color in zone 3.

159

0x9F

15:0 0x0421 Second Derivative for Zone 3 Blue Color

7:0 d2F/dx2 for zone 3 blue color.

15:8 d2F/dy2 for zone 3 blue color.

Second derivative for green color in zone 3.

160

0xA0

15:0 0x0D2A Second Derivative for Zone 4 Red Color

7:0 d2F/dx2 for zone 4 red color.

15:8 d2F/dy2 for zone 4 red color.

Second derivative for red color in zone 4.

161

0xA1

15:0 0x1017 Second Derivative for Zone 4 Green Color

7:0 d2F/dx2 for zone 4 green color.

15:8 d2F/dy2 for zone 4 green color.

Second derivative for green color in zone 4.

162

0xA2

15:0 0x1617 Second Derivative for Zone 4 Blue Color

7:0 d2F/dx2 for zone 4 blue color.

15:8 d2F/dy2 for zone 4 blue color.

Second derivative for green color in zone 4.

163

0xA3

15:0 0x1642 Second Derivative for Zone 5 Red Color

7:0 d2F/dx2 for zone 5 red color.

15:8 d2F/dy2 for zone 5 red color.

Second derivative for red color in zone 5.

164

0xA4

15:0 0x1448 Second Derivative for Zone 5 Green Color

7:0 d2F/dx2 for zone 5 green color.

15:8 d2F/dy2 for zone 5 green color.

Second derivative for green color in zone 5.

165

0xA5

15:0 0x0F4E Second Derivative for Zone 5 Blue Color

7:0 d2F/dx2 for zone 5 blue color.

15:8 d2F/dy2 for zone 5 blue color.

Second derivative for green color in zone 5.

166

0xA6

15:0 0x1F27 Second Derivative for Zone 6 Red Color

7:0 d2F/dx2 for zone 6 red color.

15:8 d2F/dy2 for zone 6 red color.

Second derivative for green color in zone 6.

167

0xA7

15:0 0x1A12 Second Derivative for Zone 6 Green Color

7:0 d2F/dx2 for zone 6 green color.

15:8 d2F/dy2 for zone 6 green color.

Second derivative for green color in zone 6.

MT9D131

www.onsemi.com

TABLE 7. IFP REGISTERS, PAGE 2 (continued)

Reg # NameDefaultBits

168

0xA8

15:0 0x1E16 Second Derivative for Zone 6 Blue Color

7:0 d2F/dx2 for zone 6 blue color.

15:8 d2F/dy2 for zone 6 blue color.

Second derivative for blue color in zone 6.

169

0xA9

15:0 0x16C7 Second Derivative for Zone 7 Red Color

7:0 d2F/dx2 for zone 7 red color.

15:8 d2F/dy2 for zone 7 red color.

Second derivative for red color in zone 7.

170

0xAA

15:0 0x31C5 Second Derivative for Zone 7 Green Color

7:0 d2F/dx2 for zone 7 green color.

15:8 d2F/dy2 for zone 7 green color.

Second derivative for green color in zone 7.

171

0xAB

15:0 0x2AB6 Second Derivative for Zone 7 Blue Color

7:0 d2F/dx2 for zone 7 blue color.

15:8 d2F/dy2 for zone 7 blue color.

Second derivative for blue color in zone 7.

172

0xAC

15:0 0x0000 X2 Factors

7:0 X2 factors for X zones. If 1 value of the value of d2F/dx2 is multiplied by 2.

15:8 X2 factors for Y zones. If 1 value of the value of d2F/dy2 is multiplied by 2.

173

0xAD

7:0 0x0002 Global Offset of F(x,y) Function

Signed 8 bit number. Value of 32 corresponds to gain of 1. Works as digital gain

174

0xAE

15:0 0x018E K Factor in K F(x) F(y)

This factor can increase lens compensation in the corners to up to 2 times.

192

0xC0

15:0 0 Boundaries of First AE Measurement Window (Top/Left)

7:0 Left window boundary.

15:8 Top window boundary.

This register specifies top and left boundaries of the first from 16 (left-top) window used by AE measurement engine.

The values programmed in the registers are desired boundaries divided by 8.

193

0xC1

15:0 0x3C50 Boundaries of First AE Measurement Window (Height/Width)

7:0 Window width.

15:8 Window height.

This register specifies height and width of the first from 16 window used by AE measurement engine. The values

programmed in the registers are desired boundaries divided by 2.

194

0xC2

15:0 0x4B00 AE Measurement Window Size (LSW)

This register number of pixels in the window used by AE measurement engine.

195

0xC3

2:0 6 AE Measurement Enable

0 0 MS bit of the AE measurement window size.

1 1 AE statistic enable.

2 1 Reserved.

This register specifies number of pixels in the window used by AE measurement engine.

196

0xC4

15:0 R/O Average Luminance in AE Windows W12 and W11

7:0 Average Y in W11 (top left).

15:8 Average Y in W12.

MT9D131

www.onsemi.com

TABLE 7. IFP REGISTERS, PAGE 2 (continued)

Reg # NameDefaultBits

197

0xC5

15:0 R/O Average Luminance in AE Windows W14 and W13

7:0 Average Y in W13.

15:8 Average Y in W14 (top right).

198

0xC6

15:0 R/O Average Luminance in AE Windows W22 and W21

7:0 Average Y in W21.

15:8 Average Y in W21.

199

0xC7

15:0 R/O Average Luminance in AE Windows W24 and W23

7:0 Average Y in W23.

15:8 Average Y in W24.

200

0xC8

15:0 R/O Average Luminance in AE Windows W32 and W31

7:0 Average Y in W31.

15:8 Average Y in W32.

201

0xC9

15:0 R/O Average Luminance in AE Windows W34 and W33

7:0 Average Y in W33.

15:8 Average Y in W34.

202

0xCA

15:0 R/O Average Luminance in AE Windows W42 and W41

7:0 Average Y in W41 (bottom left).

15:8 Average Y in W43.

203

0xCB

15:0 R/O Average Luminance in AE Windows W44 and W43

7:0 Average Y in W43.

15:8 Average Y in W44 (bottom right).

210

0xD2

9:0 0x0194 Saturation and Color Kill

2:0 4 Saturation; 100 = 100%. Scales linearly with value.

5:3 2 Color kill gain. Determines rate of gain decrease above threshold. If pixel value is above

threshold the difference is multiplied by 2^ value-1 (for 0 factor is “0”) and subtracted from the

base gain.

8:6 6 Color kill threshold. Color kill affects only pixels with value larger then 128*value.

9 0 Reserved.

211

0xD3

15:0 0 Histogram Window Lower Boundaries

7:0 X0/8.

15:8 Y0/8.

212

0xD4

15:0 0x95C7 Histogram Window Upper Boundaries

7:0 X1/8.

15:8 Y1/8.

213

0xD5

10:0 0x030A First Set of Bin Definitions

7:0 Offset for bin 0, divided by 4 on 10-bit scale.

10:8 Bin width, 0-4LSB,1-8LSB,2-16LSB,…7-512LSB on a 10-bit scale.

214

0xD6

10:0 0x030A Second Set of Bin Definitions

7:0 Offset for bin 0, divided by 4 on 10-bit scale.

10:8 Bin width, 0-4LSB,1-8LSB,2-16LSB,…7-512LSB on a 10-bit scale.

MT9D131

www.onsemi.com

TABLE 7. IFP REGISTERS, PAGE 2 (continued)

Reg # NameDefaultBits

215

0xD7

13:0 0x000A Histogram Window Size

12:0 1 Number of pixels in the window used by the histogram, set to width*height.

13 0 Select a bin set to read.

0: bin set 1

1: bin set 2

216

0xD8

15:0 0 Pixel Counts for Bin 0 and Bin 1

7:0 Pixel count for bin 0 (lowest values) divided window size, R215:2.

15:8 Pixel count for bin 1 divided by window size, R215:2.

Histogram module uses luma after interpolation. No color correction or gamma is applied. Digital gains and first black

level are applied.

This register may not be read out when image portion containing histogram window is being output.

There are two bin sets which could be read through registers 216 and 217, based on value of bit 13 in reg 215[2].

217

0xD9

15:0 0x0002 Pixel Counts for Bin 2 and Bin 3

7:0 Pixel count for bin 2 divided by G factor.

15:8 Pixel count for bin 3 (highest values) divided by G factor.

240

0xF0

2:0 2 Page Register

0: sensor core

1: IFP page1

2: IFP page 2

241

0xF1

15:0 0 Bytewise Address

Special address to perform 16-bit reads and writes to the sensor in 8-bit chunks. See “8-Bit

Write Sequence”.

MT9D131

www.onsemi.com

JPEG INDIRECT REGISTERS

TABLE 8. JPEG INDIRECT REGISTERS (See registers 30 and 31, page 2)

Reg # Bits Default Name

0x01

2:0 0 JPEG Core Register 1

1:0 0 NCol: Number of color components–1.

2 0 Re: When set, enables restart marker insertion into JPEG byte stream.

0x03

15:0 0 JPEG Core Register 3 – NRST

Re-start interval − 1. Valid only when Re in Core Register 1 is set. This register defines the number of MCUs

between Restart Markers.

0x04

7:0 0 JPEG Core Register 4

0 0 HD0: DC Huffman table pointer for color component 0.

1 0 HA0: AC Huffman table pointer for color component 0.

3:2 0 QT0: Quantization table pointer for color component 0.

7:4 0 NBlock0: Number of 8 x 8 blocks−1 for color component 0 in MCU.

0x05

7:0 0 JPEG Core Register 5

0 0 HD1: DC Huffman table pointer for color component 1.

1 0 HA1: AC Huffman table pointer for color component 1.

3:2 0 QT1: Quantization table pointer for color component 1.

7:4 0 NBlock1: Number of 8 x 8 blocks−1 for color component 1 in MCU.

0x06

7:0 0 JPEG Core Register 6

0 0 HD2: DC Huffman table pointer for color component 2.

1 0 HA2: AC Huffman table pointer for color component 2.

3:2 0 QT2: Quantization table pointer for color component 2.

7:4 0 NBlock2: Number of 8 x 8 blocks−1 for color component 2 in MCU.

0x07

7:0 0 JPEG Core Register 7

0 0 HD3: DC Huffman table pointer for color component 3.

1 0 HA3: AC Huffman table pointer for color component 3.

3:2 0 QT3: Quantization table pointer for color component 3.

7:4 0 NBlock3: Number of 8 x 8 blocks−1 for color component 3 in MCU.

0x08

15:0 0 JPEG Core Register8 – NMCU LSB

Low-order word of NMCU (NMCU = number of MCUs contained in the image to be encoded minus 1).

0x09

9:0 0 JPEG Core Register9 – NMCU_MSB

High-order word of NMCU (NMCU = number of MCUs contained in the image to be encoded minus 1).

MT9D131

www.onsemi.com

TABLE 8. JPEG INDIRECT REGISTERS (See registers 30 and 31, page 2) (continued)

Reg # NameDefaultBits

128−511

0x080 − 0x1FF

13:0 0 JPEG Quantization Memory

0 − 63: Quantization table 0

64 − 127: Quantization table 1

128 − 191: Quantization table 2

192 − 255: Quantization table 3

256 − 319: Quantization table 4

320 − 383: Quantization table 5

512 − 895

0x200 − 0x37F

11:0 0 JPEG Huffman Memory

0 − 175: AC Huffman table 0

176 − 351: AC Huffman table 1

352 − 367: DC Huffman table 0

368 − 383: DC Huffman table 1

1024 − 1407

0x400 − 0x43F

13:0 0 JPEG DCT Memory

64 x 14 dual-port RAM is accessible to host and microcontroller indirectly for testing purposes.

1408 − 1471

0x440 − 0x47F

13:0 0 JPEG Zigzag Memory 0

64 x 14 dual-port RAM is accessible to host and microcontroller indirectly for testing purposes.

1472 − 1535

0x480 − 0x4BF

13:0 0 JPEG Zigzag Memory 1

64 x 14 dual-port RAM is accessible to host and microcontroller indirectly for testing purposes.

Firmware Driver Variables

TABLE 9. DRIVERS IDs

ID VARNAME Description

0 mon Monitor

0 Reserved

1 seq Sequencer

2 ae Auto exposure

3 awb Auto white balance

4 fd Flicker detection

5 af Auto focus

6 afm Auto focus mechanics

3 awb Auto white balance

4 fd Flicker detection

5 Reserved

6 Reserved

7 mode Mode

8 Reserved

9 jpeg JPEG

12–15 Reserved

11 hg Histogram

11 Reserved

TABLE 10. DRIVERS IDs (continued)

ID Description

Driver Extensions

16 Reserved

17 Sequencer extension

18 Auto exposure extension

19 Auto white balance extension

20 Flicker detection extension

21 Reserved

22 Reserved

23 Mode extension

24 Reserved

25 JPEG extension

26 Reserved

27–31 Reserved

MT9D131

www.onsemi.com

Sequencer

TABLE 11. DRIVER VARIABLES−SEQUENCER DRIVER (ID = 1)

Offs Name Type Default RW Description

0vmt void* 61547 RW Reserved

2mode uchar 0x0F RW Set of 1-bit switches enabling various drivers and outdoor

white balance option. Writing 1 to a particular switch

enables the corresponding driver or option.

Bit 0: Auto exposure driver (ID = 2)

Bit 1: Reserved

Bit 2: Reserved

Bit 3: Reserved

Bit 4: Reserved

Bit 5: Option to force outdoor white balance settings if

exposure value exceeds

sharedParams.outdoorTH threshold.

Bits 6:7: Reserved

Bit 7: TBD

3cmd uchar 0 RW Command or program to execute

0: Run

1: Do Preview

2: Do Capture

3: Do Standby

4: Do lock

5: Refresh

6: Refresh mode

Writing a positive value to this variable commands the

sequencer to execute the corresponding program. The

sequencer resets cmd to 0, executes the program, and

then resumes running in its current state.

4state uchar 3 R Current state of sequencer

0: Initialize

1: Mode Change to Preview

2: Enter Preview

3: Preview

4: Leave Preview

5: Mode Change to Capture

6: Enter Capture

7: Capture

8: Leave Capture

9: Standby

5stepMode uchar 0 RW Step-by-step mode for sequencer

Bit 0: Step mode On/Off (1 = On)

Bit 1: 1 forces the sequencer to do next step

6sharedParams.flashType uchar 0 RW Type of flash to be used

0−None

1−LED

2−Xenon

3−Xenon burst

Bit 7−1if flash was on in LOCK mode

7sharedParams.aeContBuff uchar 8 RW Weighting factor determining to what extent AE driver

averages luma over time in continuous AE mode. Setting

of 32 disables luma averaging−only current luma values

are used. Lower settings enable luma averaging.

8sharedParams.aeContStep uchar 2 RW Number of steps in which AE driver is expected to reach

target brightness in continuous AE mode.

MT9D131

www.onsemi.com

TABLE 11. DRIVER VARIABLES−SEQUENCER DRIVER (ID = 1) (continued)

Offs DescriptionRWDefaultTypeName

9sharedParams.aeFastBuff uchar 32 RW Weighting factor determining to what extent AE driver

averages luma over time in fast mode. Setting of 32

disables luma averaging−only current luma values are

used. Lower settings enable luma averaging.

10 sharedParams.aeFastStep uchar 1 RW Number of steps in which AE driver is expected to reach

target brightness in fast AE mode.

11 sharedParams.awbContBuff uchar 8 RW Weighting factor determining to what extent AWB driver

averages luma over time in continuous AWB mode. Setting

of 32 disables luma averaging−only current luma values

are used. Lower settings enable luma averaging.

12 sharedParams.awbContStep uchar 2 RW Number of steps in which AWB driver is expected to reach

target color balance in continuous AWB mode.

13 sharedParams.awbFastBuff uchar 32 RW Weighting factor determining to what extent AWB driver

averages luma over time in fast mode. Setting of 32

disables luma averaging−only current luma values are

used. Lower settings enable luma averaging.

14 sharedParams.awbFastStep uchar 1 RW Number of steps in which AWB driver is expected to reach

target color balance in fast AWB mode.

18 sharedParams.totalMaxFrames uchar 30 RW Number of frames after which every driver must time out.

20 sharedParams.outdoorTH uchar 10 RW Exposure value (EV) threshold. If current EV is above this

threshold and bit 5 of seq.mode equals 1, AWB driver is

forced to choose color correction settings suitable for

daylight color temperature of 6500 K.

21 sharedParams.LLmode uchar 0x60 RW Bit 0: Change interpolation threshold

Bit 1: Reduce color saturation

Bit 2: Reduce aperture correction

Bit 3: Increase aperture correction threshold

Bit 4: Enable Y filter

22 sharedParams.LLvirtGain1 uchar 0x51 RW Minimum LL virtual gain. Defined as (ae.VirtGain/2 +

ae.DGainAE1/16 + ae.DGainAE2/4).

23 sharedParams.LLvirtGain2 uchar 0x5A RW Maximum LL virtual gain. Min. and max. LL virtual gains

define when low-light parameters start and stop changing.

24 sharedParams.LLSat1 uchar 128 RW Maximum color saturation for color correction matrix (128

means 100%).

25 sharedParams.LLSat2 uchar 0 RW Minimum color saturation

26 sharedParams.LLInterpThresh1 uchar 16 RW Minimum threshold for interpolation

27 sharedParams.LLInterpThresh2 uchar 64 RW Maximum threshold for interpolation

28 sharedParams.LLApCorr1 uchar 2 RW Maximum aperture correction

29 sharedParams.LLApCorr2 uchar 0 RW Minimum aperture correction

30 sharedParams.LLApThresh1 uchar 8 RW Minimum aperture correction threshold

31 sharedParams.LLApThresh2 uchar 64 RW Maximum aperture correction threshold

32 captureParams.mode uchar 0x00 RW Capture mode

Bit 0: Reserved

Bit 1: capture video

Bit 2: reserved

Bit 3: Reserved

Bit 4: AE On (video only)

Bit 5: AWB On (video only)

Bit 6: HG On (video only)

33 captureParams.numFrames uchar 3 RW Number of frames captured in still capture mode

MT9D131

www.onsemi.com

TABLE 11. DRIVER VARIABLES−SEQUENCER DRIVER (ID = 1) (continued)

Offs DescriptionRWDefaultTypeName

34 previewParams[0].ae uchar 1 RW Auto exposure configuration in PreviewEnter state

0: Off

1: Fast settling

2: Manual

3: Continuous

4: Fast settling + metering

35 previewParams[0].fd uchar 0 RW Flicker detection configuration in PreviewEnter state

0: Off

1: Manual

2: Continuous

36 previewParams[0].awb uchar 1 RW Auto white balance configuration in PreviewEnter state

0: Off

1: Fast settling

2: Manual

3: Continuous

38 previewParams[0].hg uchar 1 RW Histogram configuration in PreviewEnter state

0: Off

1: Fast

2: Manual

3: Continuous

40 previewParams[0].skipframe uchar 0x00 RW Bit 7: 1 means turn off frame enable

Bit 6: 1 means skip state

Bit 5: 1 means skip first frame when LED On

41 previewParams[1].ae uchar 3 RW Auto exposure configuration in Preview state

0: Off

1: Fast settling

2: Manual

3: Continuous

4: Fast settling + metering

42 previewParams[1].fd uchar 2 RW Flicker detection configuration in Preview state

0: Off

1: Manual

2: Continuous

43 previewParams[1].awb uchar 3 RW Auto white balance configuration in Preview state

0: Off

1: Fast settling

2: Manual

3: Continuous

45 previewParams[1].hg uchar 3 RW Histogram configuration in Preview state

0: Off

1: Fast

2: Manual

3: Continuous

47 previewParams[1].skipframe uchar 0x00 RW Bit 7: 1 means turn off frame enable

Bit 6: 1 means skip state

Bit 5: 1 means skip first frame when LED On

MT9D131

www.onsemi.com

TABLE 11. DRIVER VARIABLES−SEQUENCER DRIVER (ID = 1) (continued)

Offs DescriptionRWDefaultTypeName

48 previewParams[2].ae uchar 4 RW Auto exposure configuration in PreviewLeave state

0: Off

1: Fast settling

2: Manual

3: Continuous

4: Fast settling + metering

49 previewParams[2].fd uchar 0 RW Flicker detection configuration in PreviewLeave state

0: Off

1: Manual

2: Continuous

50 previewParams[2].awb uchar 1 RW Auto white balance configuration in PreviewLeave state

0: Off

1: Fast settling

2: Manual

3: Continuous

52 previewParams[2].hg uchar 1 RW Histogram configuration in PreviewLeave state

0: Off

1: Fast

2: Manual

3: Continuous

54 previewParams[2].skipframe uchar 0x00 RW Bit 7: 1 means turn off frame enable

Bit 6: 1 means skip state

Bit 5: 1 means skip first frame when LED On

55 previewParams[3].ae uchar 0 RW Auto exposure configuration in CaptureEnter state

0: Off

1: Fast settling

2: Manual

3: Continuous

4: Fast settling + metering

56 previewParams[3].fd uchar 0 RW Flicker detection configuration in CaptureEnter state

0: Off

1: Manual

2: Continuous

57 previewParams[3].awb uchar 0 RW Auto white balance configuration in CaptureEnter state

0: Off

1: Fast settling

2: Manual

3: Continuous

59 previewParams[3].hg uchar 0 RW Histogram configuration in CaptureEnter state

0: Off

1: Fast

2: Manual

3: Continuous

61 previewParams[3].skipframe uchar 0x00 RW Bit 7: 1 means turn off frame enable

Bit 6: 1 means skip state

Bit 5: 1 means skip first frame when LED On

MT9D131

www.onsemi.com

Auto Exposure

TABLE 12. DRIVER VARIABLES−AUTO EXPOSURE DRIVER (ID = 2)

Offs Name Type Default RW Description

0vmt void* 59518 RW Reserved

2windowPos uchar 0 RW Position of upper left corner of first AE window

Bits [3:0]: X0 in units of 1/16 of frame width

Bits [7:4]: Y0 in units 1/16 of frame height

New position written to this variable takes effect only after

REFRESH_MODE command is given to the sequencer (seq.cmd is

set to 6).

3windowSize uchar 0xEF RW Dimensions of 4 x 4 array of AE windows

Bits [3:0]: width (in units of 1/16 of frame width)

decremented by 1

Bits [7:4]: height (in units of 1/16 of frame height)

decremented by 1

New dimensions written to this variable take effect only after

REFRESH_MODE command is given to the sequencer (seq.cmd is

set to 6).

4wakeUpLine uint R Number of image row at which MCU wakes up to do AE calculations.

This number is automatically adjusted after each change of the

position and dimensions of the AE windows.

6Target uchar 60 RW Target brightness

7Gate uchar 10 RW AE sensitivity

8SkipFrames uchar 0 RW Frequency of AE updates

9JumpDivisor uchar 2 RW Factor reducing exposure jumps (1 = fastest jumps)

10 lumaBufferSpeed uchar 8 RW Speed of buffering (32 = fastest, 1 = slowest)

11 maxR12 uint 1200 RW Maximum value of R12:0 (shutter delay)

13 minIndex uchar 0 RW Minimum allowed zone number (that is minimum integration time)

14 maxIndex uchar 24 RW Maximum allowed zone number (that is maximum integration time)

15 minVirtGain uchar 16 RW Minimum allowed virtual gain

16 maxVirtGain uchar 128 RW Maximum allowed virtual gain

17 maxADChi uchar 13 RW Maximum ADC Vref_hi setting

18 minADChi uchar 11 RW Minimum ADC Vref_hi setting

19 minADClo uchar 7 RW Minimum ADC Vref_lo setting

20 maxDGainAE1 uint 128 RW Maximum digital gain pre−LC

22 maxDGainAE2 uchar 32 RW Maximum digital gain post−LC

23 IndexTH23 uchar 8 RW Zone number to start gain increase in low-light.

Sets frame rate at normal illumination.

24 maxGain23 uchar 120 RW Maximum gain to increase in low-light before dropping frame rate. Sets

frame rate at low-light.

25 weights uchar 0xFF RW Bits [7:4]: background weight

Bits [3:0]: center zone weight

26 status uchar 192 RW AE status

Bit 0: 1 if AE reached the limit

Bit 1: 1 if R9 is changed (need to skip frame)

Bit 2: ready

Bit 3: do metering mode

Bit 4: metering mode is done

Bit 6: On/Off overexpose fit

Bit 7: On/Off overexpose compensation

MT9D131

www.onsemi.com

TABLE 12. DRIVER VARIABLES−AUTO EXPOSURE DRIVER (ID = 2) (continued)

Offs DescriptionRWDefaultTypeName

27 CurrentY uchar R Last measured luminance

28 R12 uint RW Current shutter delay value

30 Index uchar R Current zone (integration time)

31 VirtGain uchar RW Current virtual gain

32 ADC_hi uchar RCurrent ADC VREF_HI value

33 ADC_lo uchar RCurrent ADC VREF_LO value

34 DGainAE1 uint RW Current digital gain pre−LC

36 DGainAE2 uchar RW Current digital gain post−LC

37 R9 uint RW Current R9:0 value (integration time)

39 R65 uchar RW Current ADC VREF values

40 rowTime uint 531 RW Row time divided by 4 (in master clock periods)

42 gainR12 uchar 128 RGain compensating too low maxR12 (128 = unit gain)

43 SkipFrames_cnt uchar R Counter of skipped frames

44 BufferedLuma uint R Current time-buffered measured luma

46 dirAE_prev uchar R Previous state of AE

47 R9_step uint 157 RW Integration time of one zone

50 maxADClo uchar R Maximum ADC Vref_lo setting

51 physGainR uint R Physical (analog) R gain

53 physGainG uint R Physical (analog) G gain

55 physGainB uint R Physical (analog) B gain

82 mmEVZone1 uchar 16 RW EV threshold for scenes containing the sun

83 mmEVZone2 uchar 12 RW EV threshold for bright outdoor scenes

84 mmEVZone3 uchar 8 RW EV threshold for indoor or outdoor twilight scenes

85 mmEVZone4 uchar 2 RW EV threshold for night scenes

86 mmShiftEV uchar 13 RW Exposure Value shift. Adjust this value for given lens.

87 numOE uchar R Number of overexposed zones

Auto White Balance

TABLE 13. DRIVER VARIABLES−AUTO WHITE BALANCE (ID = 3)

Offs Name Type Default RW Description

0 vmt void* 59731 RW Reserved

2 windowPos uchar 0 RW Position of upper left corner of AWB window

Bits [3:0]: X0 in units of 1/16th of frame width

Bits [7:4]: Y0 in units 1/16th of frame height

New position written to this variable takes effect only after

REFRESH_MODE command is given to the sequencer (seq.cmd is

set to 6).

3 windowSize uchar 0xEF RW Dimensions of AWB window

Bits [3:0]: width (in units of 1/16th of frame width)

decremented by 1.

Bits [7:4]: height (in units of 1/16th of frame height) .

decremented by 1

New dimensions written to this variable take effect only after

REFRESH_MODE command is given to the sequencer (seq.cmd is

set to 6).

MT9D131

www.onsemi.com

TABLE 13. DRIVER VARIABLES−AUTO WHITE BALANCE (ID = 3) (continued)

Offs DescriptionRWDefaultTypeName

4 wakeUpLine uint R Number of image row at which MCU wakes up to perform AWB

calculations. This number is automatically adjusted after each change

of the position and dimensions of the AWB window.

6 ccmL[0] int 0x0219 RW Left color correction matrix element K11. Value is encoded in signed

two’s complement form; 256 means 1.0. New values written to

awb.ccmL array take effect only after REFRESH command is given to

the sequencer (seq.cmd is set to 5).

8 ccmL[1] int 0xFEEC RW Left color correction matrix element K12

10 ccmL[2] int 0xFFFF RW Left color correction matrix element K13

12 ccmL[3] int 0xFF6A RW Left color correction matrix element K21

14 ccmL[4] int 0x01D4 RW Left color correction matrix element K22

16 ccmL[5] int 0xFFC9 RW Left color correction matrix element K23

18 ccmL[6] int 0xFF71 RW Left color correction matrix element K31

20 ccmL[7] int 0xFDD3 RW Left color correction matrix element K32

22 ccmL[8] int 0x03ED RW Left color correction matrix element K33

24 ccmL[9] int 0x0020 RW Left color correction matrix red/green gain ratio.

Value is interpreted as unsigned; 32 means 1.0.

26 ccmL[10] int 0x0035 RW Left color correction matrix blue/green gain ratio.

Value is interpreted as unsigned; 32 means 1.0.

28 ccmRL[0] int 0xFF92 RW Delta color correction matrix element D11. Value is encoded in signed

two’s complement form; 256 means 1.0. New values written to

awb.ccmRL array take effect only after REFRESH command is given

to the sequencer (seq.cmd is set to 5).

30 ccmRL[1] int 0x0098 RW Delta color correction matrix element D12

32 ccmRL[2] int 0xFFE1 RW Delta color correction matrix element D13

34 ccmRL[3] int 0x0014 RW Delta color correction matrix element D21

36 ccmRL[4] int 0xFFFC RW Delta color correction matrix element D22

38 ccmRL[5] int 0xFFF2 RW Delta color correction matrix element D23

40 ccmRL[6] int 0x004E RW Delta color correction matrix element D31

42 ccmRL[7] int 0x0148 RW Delta color correction matrix element D32

44 ccmRL[8] int 0xFE3F RW Delta color correction matrix element D33

46 ccmRL[9] int 0x000A RW Delta color correction matrix red/green gain ratio.

Value is interpreted as unsigned; 32 means 1.0.

48 ccmRL[10] int 0xFFF1 RW Delta color correction matrix blue/green gain ratio.

Value is interpreted as unsigned; 32 means 1.0.

50 ccm[0] int RW Current color correction matrix element C11.

Value is stored in signed two’s complement form; 256 means 1.0.

52 ccm[1] int RW Current color correction matrix element C12

54 ccm[2] int RW Current color correction matrix element C13

56 ccm[3] int RW Current color correction matrix element C21

58 ccm[4] int RW Current color correction matrix element C22

60 ccm[5] int RW Current color correction matrix element C23

62 ccm[6] int RW Current color correction matrix element C31

64 ccm[7] int RW Current color correction matrix element C32

66 ccm[8] int RW Current color correction matrix element C33

MT9D131

www.onsemi.com

TABLE 13. DRIVER VARIABLES−AUTO WHITE BALANCE (ID = 3) (continued)

Offs DescriptionRWDefaultTypeName

68 ccm[9] int RW Current color correction matrix red/green gain ratio.

Value is interpreted as unsigned; 32 means 1.0.

70 ccm[10] int RW Current color correction matrix blue/green gain ratio.

Value is interpreted as unsigned; 32 means 1.0.

72 GainBufferSpeed uchar 8 RW Speed of time-buffering (32 = fastest, 1= slowest)

73 JumpDivisor uchar 2 RW Derating factor for white balance changes (1= fastest changes)

74 GainMin uchar 83 RW Minimum allowed AWB digital gain (128 means 1.0)

75 GainMax uchar 192 RW Maximum allowed AWB digital gain (128 means 1.0)

76 GainR uchar R Current R digital gain (128 means1.0)

77 GainG uchar R Current G digital gain (128 means1.0)

78 GainB uchar R Current B digital gain (128 means 1.0)

79 CCMpositionMin uchar 0 RW Leftmost position of color correction matrix (corresponding to

incandescent light)

80 CCMpositionMax uchar 127 RW Rightmost position of color correction matrix (corresponding to

daylight)

81 CCMposition uchar 64 RW Current position of color correction matrix (0 corresponds to

incandescent light, 127 to daylight)

82 saturation uchar 128 RW Saturation of color correction matrix (128 means 100%)

83 mode uchar 0 RW Bit 0−1 = AWB is in steady state

Bit 1−1 = limits are reached

Bit 2−1 = reserved

Bit 3−1 = debug

Bit 4−1 = no awb statistic

Bit 5−1 = force AWB DGains to unit; program value

into awb.CCMPosition to manually set matrix position

Bit 6−1 = disable CCM normalization

Bit 7−1 = force outdoor settings, set by the sequencer

84 GainR_buf uint 0x1000 RW Time-buffered R gain (0x1000 means 1.0)

86 GainB_buf uint 0x1000 RW Time-buffered B gain (0x1000 means 1.0)

88 sumR uchar R AWB statistics (normalized to an arbitrary number)

89 sumY uchar R AWB statistics (normalized to an arbitrary number)

90 sumB uchar R AWB statistics (normalized to an arbitrary number)

91 steadyBGainOutMin uchar 115 RW Blue gain min. threshold to start search. When the blue gain falls

below this threshold, the AWB driver starts searching for new color

correction matrix position. Threshold setting of 128 corresponds to

gain of 1.0; higher setting means higher gain.

92 steadyBGainOutMax uchar 140 RW Blue gain max. threshold to start search. When the blue gain goes

above this threshold, the AWB driver starts searching for new color

correction matrix position. Threshold setting of 128 corresponds to

gain of 1.0; higher setting means higher gain.

93 steadyBGainInMin uchar 124 RW Blue gain min. threshold to end search. When the blue gain is between

awb.steadyBGainInMin and awb.steadyBGainInMax, the AWB driver

maintains current color correction matrix position. Threshold setting of

128 corresponds to gain of 1.0; higher setting means higher gain.

94 steadyBGainInMax uchar 131 RW Blue gain max. threshold to end search.

See awb.steadyBGainInMin above.

95 cntPxlTH uint 100 RW Reserved

97 TG_min0 uchar 226 RW Reserved

98 TG_max0 uchar 246 RW Reserved

MT9D131

www.onsemi.com

TABLE 13. DRIVER VARIABLES−AUTO WHITE BALANCE (ID = 3) (continued)

Offs DescriptionRWDefaultTypeName

99 XO 16 RW CCM position threshold between Day and Incandescent normalization

coefficients.

100 kR_L uchar 170 RW CCM red row normalization coefficient for left matrix position

(128 − minimal number)

101 kG_L uchar 150 RW CCM green row normalization coefficient for left matrix position

(128 − minimal number)

102 kB_L uchar 128 RW CCM blue row normalization coefficient for left matrix position

(128 − minimal number)

103 kR_R uchar 128 RW CCM red row normalization coefficient for right matrix position

(128 − minimal number)

104 kG_R uchar 128 RW CCM green row normalization coefficient for right matrix position

(128 − minimal number)

105 kB_R uchar 128 RW CCM blue row normalization coefficient for right matrix position

(128 − minimal number)

Flicker Detection

TABLE 14. DRIVER VARIABLES−FLICKER DETECTION DRIVER (ID = 4)

Offs Name Type Default RW Description

0 vmt void* 59884 RW Reserved

2 windowPosH uchar 29 RW Width of flicker measurement window and position of its left boundary

Bits [3:0]: width (in units of 1/16th of frame width)

decremented by 1

Bits [7:4]: X0 (in the same units as the width)

At the beginning of each flicker measurement, the top boundary (Y0)

of the flicker measurement window is set at row 64. Average

luminance in the window is measured by the IFP measurement engine

and stored in fd.Buffer[0]. Then Y0 is incremented by fd.windowHeight

and the buffer index by 1. By repeating these steps 47 times, the entire

fd.Buffer is filled with average luminance values from a vertical array of

48 equal-size windows.

3 windowHeight uchar 4RW Bits [5:0]: flicker measurement window height in rows

4 mode uchar 0 RW Mode switches and indicators

Bit 7 −1 enables manual mode, 0 disables it

Bit 6 −0 selects 60 Hz settings for manual mode, 1

selects 50 Hz settings

Bit 5 −read-only, indicates current settings

(0–60 Hz, 1–50 Hz)

Bit 4 −1 enables debug mode, 0 disables it

Bits [3:0]-read-only, reserved for auto FD

5 wakeUpLine uint 64 R Number of image row at which MCU wakes up to perform flicker

detection. Changing the value of fd.wakeUpLine has no effect on the

functioning of the FD driver, because it does not use this variable. It

simply sets it to 64 at initialization, to indicate the top of the flicker

measurement area. See fd.windowPosH above.

7 smooth_cnt uchar 5RW Reserved

8 search_f1_50 uchar 30 RW Lower limit of period range of interest in 50 Hz flicker detection. If the

FD driver is searching for 50 Hz flicker and detects in a frame a

flicker-like signal whose period in rows is between fl.search_f1_50 and

fl.search_f2_50, it counts the frame as one containing flicker.

9 search_f2_50 uchar 32 RW Upper limit of period range of interest in 50 Hz flicker detection. See

fd.search_f1_50 above.

MT9D131

www.onsemi.com

TABLE 14. DRIVER VARIABLES−FLICKER DETECTION DRIVER (ID = 4) (continued)

Offs DescriptionRWDefaultTypeName

10 search_f1_60 uchar 37 RW Lower limit of period range of interest in 60 Hz flicker detection. If the

FD driver is searching for 60 Hz flicker and detects in a frame a

flicker-like signal whose period in rows is between fl.search_f1_60 and

fl.search_f2_60, it counts the frame as one containing flicker.

11 search_f2_60 uchar 39 RW Upper limit of period range of interest in 60 Hz flicker detection. See

fd.search_f1_60 above.

12 skipFrame uchar 0RW Skip frame before subtracting two frames.

13 stat_min uchar 3RW Flicker is considered detected if fd.stat_min out of fd.stat_max

consecutive frames contain flicker

(periodic signal of sought frequency).

14 stat_max uchar 5RW See fl.stat_min.

15 stat uchar R Reserved

16 minAmplitude uchar 5RW Reserved

17 R9_step60 uint 157 RW Minimal shutter width step for 60 Hz AC

19 R9_step50 uint 188 RW Minimal shutter width step for 50 Hz AC

21 Buffer[48] Uchar

[48]

R Reserved

Context

TABLE 15. DRIVER VARIABLES−MODE/CONTEXT DRIVER (ID = 7)

Offs Name Type ASSOC.H/W Reg RW Default Description

0VMT Pointer uint local RW 59871 Pointer to virtual method table.

2 context uchar local RW 0Current context (0 = A, 1 = B).

3output width_A uint R0x16:1 RW 800 Output size of final image for context A.

Must be equal to or smaller than crop dimension.

5output height_A uint R0x17:1 RW 600 Output size of final image for context A.

Must be equal to or smaller than crop dimension.

7output width_B uint R0x16:1 RW 1600 Output size of final image for context B.

Must be equal to or smaller than crop dimension.

9output height_B uint R0x17:1 RW 1200 Output size of final image for context B.

Must be equal to or smaller than crop dimension.

11 mode_config uint R0xA:2 RW 0x10 Bit 4: JPG bypass: context A.

Bit 5: JPG bypass: context B.

Set to “0” to enable JPEG.

13 PLL_lock_delay uint local RW 200 Delay between PLL enable and start of

microcontroller operation

(no. of clock cycles x 100).

15 s_row_start_A uint R0x01:0 RW 28 First sensor-readout row

(context A shadow register).

17 s_col_start_A uint R0x02:0 RW 60 First sensor-readout column

(context A shadow register).

19 s_row_height_A uint R0x03:0 RW 1200 Number of sensor-readout rows

(context A shadow register).

21 s_col_width_A uint R0x04:0 RW 1600 Number of sensor-readout columns

(context A shadow register).

23 s_ext_delay_A uint R0x0B:0 RW 0Extra sensor delay per frame

(context A shadow register).

25 s_row_speed_A uint R0x0A:0 RW 1Row speed (context A shadow register).

MT9D131

www.onsemi.com

TABLE 15. DRIVER VARIABLES−MODE/CONTEXT DRIVER (ID = 7) (continued)

Offs DescriptionDefaultRWASSOC.H/W RegTypeName

27 s_row_start_B uint R0x01:0 RW 28 First sensor-readout row

(context B shadow register).

29 s_col_start_B uint R0x02:0 RW 60 First sensor-readout column

(context B shadow register).

31 s_row_height_B uint R0x03:0 RW 1200 Number of sensor-readout rows

(context B shadow register).

33 s_col_width_B uint R0x04:0 RW 1600 Number of sensor-readout columns

(context B shadow register).

35 s_ext_delay_B uint R0x0B:0 RW 1050 Extra sensor delay per frame

(context B shadow register).

37 s_row_speed_B uint R0x0A:0 RW 1Row speed (context B shadow register).

39 crop_X0_A uint R0x11:1 RW 0Lower−x decimator zoom window

(context A shadow register).

41 crop_X1_A uint R0x12:1 RW 800 Upper−x decimator zoom window

(context A shadow register).

43 crop_Y0_A uint R0x13:1 RW 0Lower−y decimator zoom window

(context A shadow register).

45 crop_Y1_A uint IR0x14:1 /W 600 Upper−y decimator zoom window

(context A shadow register).

47 dec_ctrl_A uint R0x15:1 R/W 0 Decimator control register

(context A shadow register).

53 crop_X0_B uint R0x11:1 RW 0Lower−x decimator zoom window

(context B shadow register).

55 crop_X1_B uint R0x12:1 RW 1600 Upper−x decimator zoom window

(context B shadow register)

57 crop_Y0_B uint R0x13:1 RW 0Lower−y decimator zoom window

(context B shadow register).

59 crop_Y1_B uint R0x14:1 RW 1200 Upper−y decimator zoom window

(context B shadow register).

61 dec_ctrl_B uint R0x15:1 RW 0Decimator control register

(context B shadow register).

67 gam_cont_A uchar local RW 0x42 Gamma and contrast settings

(context A shadow register)

Gamma Setting: Bits 0:2:

0: gamma = 1.0

1: gamma = 0.56

2: gamma = 0.45

3: use user-defined gamma table

Contrast Setting: Bits 4:6:

0: no contrast increase (slope = 100%)

1: some contrast increase (slope = 125%)

2: more contrast increase (slope = 150%)

3: most contrast increase (slope = 175%)

4: noise-reduction contrast

MT9D131

www.onsemi.com

TABLE 15. DRIVER VARIABLES−MODE/CONTEXT DRIVER (ID = 7) (continued)

Offs DescriptionDefaultRWASSOC.H/W RegTypeName

68 gam_cont_B uchar local RW 0x42 Gamma and contrast settings

(context B shadow register)

Gamma Setting: Bits 0:2:

0: gamma = 1.0

1: gamma = 0.56

2: gamma = 0.45

3: use user-defined gamma table

Contrast Setting: Bits 4:6:

0: no contrast increase (slope = 100%)

1: some contrast increase (slope = 125%)

2: more contrast increase (slope = 150%)

3: most contrast increase (slope = 175%)

4: noise-reduction contrast

69 gamma_table_A_0 uchar R0xB2:1[7:0] RW 0User-defined gamma table values

(context A shadow register).

70 gamma_table_A_1 uchar R0xB2:1[15:8] RW 39 User-defined gamma table values

(context A shadow register).

71 gamma_table_A_2 uchar R0xB3:1[7:0] RW 53 User-defined gamma table values

(context A shadow register).

72 gamma_table_A_3 uchar R0xB3:1[15:8] RW 72 User-defined gamma table values

(context A shadow register).

73 gamma_table_A_4 uchar R0xB4:1[7:0] RW 99 User-defined gamma table values

(context A shadow register).

74 gamma_table_A_5 uchar R0xB4:1[15:8] RW 119 User-defined gamma table values

(context A shadow register).

75 gamma_table_A_6 uchar R0xB5:1[7:0] RW 136 User-defined gamma table values

(context A shadow register).

76 gamma_table_A_7 uchar R0xB5:1[15:8] RW 150 User-defined gamma table values

(context A shadow register).

77 gamma_table_A_8 uchar R0xB6:1[7:0] RW 163 User-defined gamma table values

(context A shadow register).

78 gamma_table_A_9 uchar R0xB6:1[15:8] RW 175 User-defined gamma table values

(context A shadow register).

79 gamma_table_A_10 uchar R0xB7:1[7:0] RW 186 User-defined gamma table values

(context A shadow register).

80 gamma_table_A_11 uchar R0xB7:1[15:8] RW 196 User-defined gamma table values

(context A shadow register).

81 gamma_table_A_12 uchar R0xB8:1[7:0] RW 206 User-defined gamma table values

((context A shadow register).

82 gamma_table_A_13 uchar R0xB8:1[15:8] RW 215 User-defined gamma table values

(context A shadow register).

83 gamma_table_A_14 uchar R0xB9:1[7:0] RW 224 User-defined gamma table values

(context A shadow register).

84 gamma_table_A_15 uchar R0xB9:1[15:8] RW 232 User-defined gamma table values

(context A shadow register).

85 gamma_table_A_16 uchar R0xBA:1[7:0] RW 240 User-defined gamma table values

(context A shadow register).

86 gamma_table_A_17 uchar R0xBA:1[15:8] RW 248 User-defined gamma table values

(context A shadow register).

87 gamma_table_A_18 uchar R0xBB:1[7:0] RW 255 User-defined gamma table values

(context A shadow register).

MT9D131

www.onsemi.com

TABLE 15. DRIVER VARIABLES−MODE/CONTEXT DRIVER (ID = 7) (continued)

Offs DescriptionDefaultRWASSOC.H/W RegTypeName

88 gamma_table_B_0 uchar R0xB2:1[7:0] RW 0User-defined gamma table values

(context B shadow register).

89 gamma_table_B_1 uchar R0xB2:1[15:8] RW 39 User-defined gamma table values

(context B shadow register).

90 gamma_table_B_2 uchar R0xB3:1[7:0] RW 53 User-defined gamma table values

(context B shadow register).

91 gamma_table_B_3 uchar R0xB3:1[15:8] RW 72 User-defined gamma table values

(context B shadow register).

92 gamma_table_B_4 uchar R0xB4:1[7:0] RW 99 User-defined gamma table values

(context B shadow register).

93 gamma_table_B_5 uchar R0xB4:1[15:8] RW 119 User-defined gamma table values

(context B shadow register).

94 gamma_table_B_6 uchar R0xB5:1[7:0] RW 136 User-defined gamma table values

(context B shadow register).

95 gamma_table_B_7 uchar R0xB5:1[15:8] RW 150 User-defined gamma table values

(context B shadow register).

96 gamma_table_B_8 uchar R0xB6:1[7:0] RW 163 User-defined gamma table values

(context B shadow register).

97 gamma_table_B_9 uchar R0xB6:1[15:8] RW 175 User-defined gamma table values

(context B shadow register).

98 gamma_table_B_10 uchar R0xB7:1[7:0] RW 186 User-defined gamma table values

(context B shadow register).

99 gamma_table_B_11 uchar R0xB7:1[15:8] RW 196 User-defined gamma table values

(context B shadow register).

100 gamma_table_B_12 uchar R0xB8:1[7:0] RW 206 User-defined gamma table values

(context B shadow register).

101 gamma_table_B_13 uchar R0xB8:1[15:8] RW 215 User-defined gamma table values

(context B shadow register).

102 gamma_table_B_14 uchar R0xB9:1[7:0] RW 224 User-defined gamma table values

(context B shadow register).

103 gamma_table_B_15 uchar R0xB9:1[15:8] RW 232 User-defined gamma table values

(context B shadow register).

104 gamma_table_B_16 uchar R0xBA:1[7:0] RW 240 User-defined gamma table values

(context B shadow register).

105 gamma_table_B_17 uchar R0xBA:1[15:8] RW 248 User-defined gamma table values

(context B shadow register).

106 gamma_table_B_18 uchar R0xBB:1[7:0] RW 255 User-defined gamma table values

(context B shadow register).

107 FIFO_config0_A uint R0x0D:2 RW 0x0027 FIFO Buffer configuration 0

(context A shadow register).

109 FIFO_config1_A uint R0x0E:2 RW 0x0002 FIFO Buffer configuration 1

(context A shadow register).

111 FIFO_config2_A uchar R0x0F:2 RW 0x21 FIFO Buffer configuration 2

(context A shadow register).

112 FIFO_len_timing_A uint R0x12:2 RW 0x0606 FIFO spoof frame line timing

(context B shadow register).

114 FIFO_config0_B uint R0x0D:2 RW 0x0067 FIFO Buffer configuration 0

(context B shadow register).

116 FIFO_config1_B uint R0x0E:2 RW 0x050A FIFO Buffer configuration 1

(context B shadow register).

MT9D131

www.onsemi.com

TABLE 15. DRIVER VARIABLES−MODE/CONTEXT DRIVER (ID = 7) (continued)

Offs DescriptionDefaultRWASSOC.H/W RegTypeName

118 FIFO_config2_B uchar R0x0F:2 RW 0x0003 FIFO Buffer configuration 2

(context B shadow register).

119 FIFO_len_timing_B uint R0x12:2 RW 0x0606 FIFO spoof frame line timing

(context B shadow register).

121 spoof_width_B uint R0x10:2* RW 1600 FIFO spoof frame line timing

(context B shadow register).

*If in uncompressed mode, 2x this value is

uploaded to R0x10.

123 spoof_height_B uint R0x11:2 RW 600 FIFO spoof frame line timing

(context B shadow register).

125 out_format_A uchar R0x97:1 RW 0Output Format Config. (context A shadow register).

126 out_format_B uchar R0x97:1 RW 0Output Format Config. (context B shadow register).

127 spec_effects_A uint R0xA4:1 RW 0x6440 Special effects selection

(context A shadow register).

129 spec_effects_B uint R0xA4:1 RW 0x6440 Special effects selection

(context B shadow register).

131 y_rgb_offset_A uchar R0xBF:1 RW 0Y/RGB Offset setting (context A shadow register).

132 y_rgb_offset_B uchar R0xBF:1 RW 0Y/RGB Offset setting (context B shadow register).

JPEG

TABLE 16. DRIVER VARIABLES−JPEG DRIVER (ID = 9)

Offs Name Type Default RW Description

0 vmt void* 58451 RW Reserved.

2 width uint 1600 R Image width (see mode.output_width).

4 height uint 1200 R Image height (see mode.output_height).

6 format uchar

0RW

Image format:

0: YCbCr 4:2:2

1: YCbCr 4:2:0

2: Monochrome

7 config uchar

52 RW

Configuration and handshaking:

Bit 0: if 1, video; if 0, still snapshot

Bit 1: enable handshaking with host at every error frame

Bit 2: enable retry after an unsuccessful encode or transfer

Bit 3: host indicates it is ready for next frame

Bit 4: enable scaled quantization table generation

Bit 5: enable auto−select quantization table

Bit 7:6: quantization table ID

8 restartInt uint 0RW Restart marker interval:

0 = restart marker is disabled

10 qscale1 uchar 6RW Bit 6:0: scaling factor for first set of quantization tables

Bit 7: 1, new scaling factor value

11 qscale2 uchar 9RW Bit 6:0: scaling factor for second set of quantization tables

Bit 7: if 1, new scaling factor value

12 qscale3 uchar 12 RW Bit 6:0: scaling factor for third set of quantization tables

Bit 7: if 1, new scaling factor value

13 timeoutFrames uchar 10 RW Number of frames to time out when host is not responding (setting bit

3 of config) to an unsuccessful JPEG frame while bit 1 of config is set.

MT9D131

www.onsemi.com

TABLE 16. DRIVER VARIABLES−JPEG DRIVER (ID = 9) (continued)

Offs DescriptionRWDefaultTypeName

14 state uchar 0 R JPEG driver state.

15 dataLengthMSB uchar R Bit [23:16] of previous frame JPEG data length.

16 dataLengthLSBs uint R Bit [15:0] of previous frame JPEG data length.

OUTPUT FORMAT AND TIMING

YUV/RGB Uncompressed Output

Uncompressed YUV or RGB data can be output either

directly from the output formatting block or through a FIFO

buffer with a capacity of 1,600 bytes, enough to hold one half

uncompressed line at full resolution. Buffering of data is a

way to equalize the data output rate when image decimation

is used. Decimation produces an intermittent data stream

consisting of short high-rate bursts separated by idle periods.

Figure 6 depicts such a stream. High pixel clock frequency

during bursts may be undesirable due to EMI concerns.

Figure 6. Timing of Decimated Uncompressed Output Bypassing the FIFO

FRAME_VALID

LINE_VALID

PIXCLK

LINE_VALID

BT.601 code Pixel Data Pixel Data BT.601 Code

OUT

Figure 7 depicts the output timing of uncompressed

YUV/RGB when a decimated data stream is equalized by

buffering or when no decimation takes place. The pixel

clock frequency remains constant during each

LINE_VALID high period. Decimated data are output at a

lower frequency than full size frames, which helps to reduce

EMI.

Figure 7. Timing of Uncompressed Full Frame Output or Decimated Output Passing Through the FIFO

FRAME_VALID

LINE_VALID

PIXCLK

[7:0]

OUT

Timing details of uncompressed YUV/RGB output are

shown in Figure 8.

MT9D131

www.onsemi.com

Figure 8. Details of uncompressed YUV/RGB Output Timing

PIXCLK

Data[7:0]

LINE_VALID

XXX

Note: FRAME_VALID leads LINE_VALID by 6 PIXCLKs.

Note: FRAME−VALID trails

LINE_VALID by 6 PIXCLKs.

tPFL

tPLL

tPD tPD

tPFH

tPLH

Pxl_0 Pxl_1 Pxl_2 Pxl_n

XXX XXX XXX XXX

FRAME_VALID/

TABLE 17. DETAILS OF UNCOMPRESSED YUV/RGB OUTPUT TIMING

Symbol Definition Conditions Min Max Units

fPIXCLK PIXCLK frequency Default 80 MHz

tPD PIXCLK to data valid Default −3 3 ns

tPFH PIXCLK to FV high Default −3 3 ns

tPLH PIXCLK to LV high Default −3 3 ns

tPFL PIXCLK to FV low Default −3 3 ns

tPLL PIXCLK to LV low Default −3 3 ns

Uncompressed YUV/RGB Data Ordering

The MT9D131 supports swapping YCrCb mode, as

illustrated in Table 17.

TABLE 18. YCrCb OUTPUT DATA ORDERING

Mode

Default (no swap) CbiYiCriYi+1

Swapped CrCb CriYiCbiYi+1

Swapped YC YiCbiYi+1 Cri

Swapped CrCb, YC YiCriYi+1 Cbi

The RGB output data ordering in default mode is shown

in Table 18. The odd and even bytes are swapped when

luma/chroma swap is enabled. R and B channels are bit-wise

swapped when chroma swap is enabled.

TABLE 19. RGB ORDERING IN DEFAULT MODE

Mode (Swap Disabled) Byte D7D6D5D4D3D2D1D0

565RGB Odd R7R6R5R4R3G7G6G5

Even G4G3G2B7B6B5B4B3

555RGB Odd 0 R7R6R5R4R3G7G6

Even G4G3G2B7B6B5B4B3

444xRGB Odd R7R6R5R4G7G6G5G4

Even B7B6B5B4 0 0 0 0

x444RGB Odd 0 0 0 0 R7R66R5R4

Even G7G6G5G4B7B6B5B4

MT9D131

www.onsemi.com

Uncompressed 10-Bit Bypass Output

Raw 10-bit Bayer data from the sensor core can be output

in bypass mode by using the eight output signals

(DOUT[7:0]) in a special 8 + 2 data format, as shown in

Table 19.

The timing of 10-bit or 8-bit data stream output in the

bypass mode is qualitatively the same as that depicted in

Figure 7.

TABLE 20. 2-BYTE RGB FORMAT

Odd Bytes 8 Data Bits D9D8D7D6D5D4D3D2

Even bytes 2 data bits + 6 unused bits 0 0 0 0 0 0 D1 D0

0 Y1

Figure 9. Example of Timing for Non−Decimated Uncompressed Output Bypassing Output FIFO

0xFF 0x00 0x00 0xAB 0xFF 0x00 0x00 0x80 Cb

0 Y 0 Cr

Cb0 Y 0 Cr 0 Y 10xFF 0x00 0x00 0x9D 0xFF 0x00 0x00 0xB6

JPEG Compressed Output

JPEG compression of IFP output produces a data stream

whose structure differs from that of an uncompressed

YUV/RGB stream. Frames are no longer sequences of lines

of constant length. This difference is reflected in the timing

of the LINE_VALID signal. When JPEG compression is

enabled, logical HIGHs on LINE_VALID do not correspond

to image lines, but to variably sized packets of valid data. In

other words, the LINE_VALID signal is in fact a

DATA_VALID signal. It is a good analogy to compare the

JPEG output of the MT9D131 to an 8-bit parallel data port

wherein the LINE_VALID signal indicates valid data and

the FRAME_VALID signal indicates frame timing.

The JPEG compressed data can be output either

continuously or in blocks simulating image lines. The latter

output scheme is intended to spoof a standard video pixel

port connected to the MT9D131 and for that purpose treats

JPEG entropy-coded segments as if they were standard

video pixels. In the continuous output mode, JPEG output

clock can be free-running or gated. In all, three timing modes

are available and are depicted in Figure 10, Figure 11 and

Figure 12. These timing diagrams are merely three typical

examples of many variations of JPEG output. Description of

output configuration register R0xD:2 in Table 6, “IFP

Registers, Page 2,” provides more information on different

output interface configuration options.

The “continuous” and spoof JPEG output modes differ

primarily in how the LINE_VALID output is asserted. In the

continuous mode, LINE_VALID is asserted only during

output clock cycles containing valid JPEG data. The

resulting LINE_VALID signal pattern is non-uniform and

highly image-dependent, reflecting the inherent nature of

JPEG data stream. In the spoof mode, LINE_VALID is

asserted and de-asserted in a more uniform pattern

emulating uncompressed video output with horizontal

blanking intervals. When LINE_VALID is de-asserted,

available JPEG data are not output, but instead remain in the

FIFO until LINE_VALID is asserted again. During the time

when LINE_VALID is asserted, the output clock is gated off

whenever there is no valid JPEG data in the FIFO.

NOTE: As a result, spoof “lines” containing the same

number of valid data bytes may be output within

different time intervals depending on constantly

varying JPEG data rate.

The host processor configures the spoof pattern by

programming the total number of LINE_VALID assertion

intervals, as well as the number of output clock periods

during and between LINE_VALID assertions. In other

words, the host processor can define a temporal “frame” for

JPEG output, preferably with “size” tailored to the expected

JPEG file size. If this frame is too large for the total number

of JPEG bytes actually produced, the MT9D131 either

de-asserts FRAME_VALID or continues to pad unused

“lines” with zeros until the end of the frame. If the frame is

too small, the MT9D131 either continues to output the

excess JPEG bytes until the entire JPEG compressed image

is output or discards the excess JPEG bytes and sets an error

flag in a status register accessible to the host processor.

MT9D131

www.onsemi.com

In the continuous output mode, the JPEG output clock can

be configured to be either gated off or running while

LINE_VALID is de-asserted. To save extra power, the JPEG

output clock can also be gated off between frames (when

FRAME_VALID is de-asserted) in both continuous and

spoof output mode. In the continuous output mode, there is

an option to insert JPEG SOI (0xFFD8) and EOI (0xFFD9)

markers respectively before and after valid JPEG data. SOI

and EOI can be inserted either inside or outside the

FRAME_VALID assertion period, but always outside

LINE_VALID assertions.

The output order of even and odd bytes of JPEG data can

be swapped in the spoof output mode. This option is not

supported in the continuous mode.

Output clock speed can optionally be made to vary

according to the fullness of the FIFO, to reduce the

likelihood of FIFO overflow. When this option is enabled,

the output clock switches at three fixed levels of FIFO

fullness (25 percent, 50 percent, and 75 percent) to a higher

or lower frequency, depending on the direction of fullness

change. The set of possible output clock frequencies is

restricted by the fact that its period must be an integer

multiple of the master clock period. The frequencies to be

used are chosen by programming three output clock

frequency divisors in registers R0xE:2 and R0xF:2. Divisor

N1 is used if the FIFO is less than 50 percent full and last

fullness threshold crossed has been 25 percent. When the

FIFO reaches 50 percent and 75 percent fullness, the output

clock switches to divisor N2 and N3, respectively. When the

FIFO fullness level drops to 50 percent and 25 percent, the

output clock is switched back to divisor N2 and N1,

respectively.

The host processor can read registers containing JPEG

status flags and JPEG data length (total byte count of valid

JPEG data) through a two-wire serial interface. In addition,

the JPEG data length and JPEG status byte are always

appended at the end of JPEG spoof frame. JPEG status byte

can be optionally appended at the end of JPEG continuous

frame. JPEG data stream sent to the host does not have a

header.

Figure 10. Timing of JPEG Compressed Output in Free-Running Mode

PIXCLK

FRAME_VALID

LINE_VALID

D0−D7

First JPEG Byte Last JPEG Byte

Status Byte

OUT OUT

Figure 11. Timing of JPEG Compressed Output in Gated Clock Mode

PIXCLK

FRAME_VALID

LINE_VALID

SOI

First JPEG Byte Last JPEG Byte

EOI

D0−D7

OUT OUT

MT9D131

www.onsemi.com

Figure 12. Timing of JPEG Compressed Output in Spoof Mode

FRAME_VALID

LINE_VALID

j0 = JPEG_data_length [7:0]

j1 = JPEG_data_length [15:8]

j2 = JPEG_data_length [23:16]

s = Status byte

Padded Data

j0 j1 j2 s

D0−D7

OUT OUT

PIXCLK

In the spoof mode, the timing of FRAME_VALID and

LINE_VALID mimics an uncompressed output. The timing

of PIXCLK and DOUT within each LINE_VALID assertion

period is variable and therefore unlike that of uncompressed

data. Valid JPEG data are padded with dummy data to the

size of the original uncompressed frame.

Color Conversion Formulas

Y’Cb’Cr’ ITU−R BT.601

A widely known color conversion standard. Note that 16

< Y601 < 235 and 16 < Cb, Cr < 240. 0 < = RGB < = 255.

Y601’ = Y’*219/256 + 16

Cr’ = 0.713 (R’ − Y’)*224/256 + 128

Cb’ = 0.564 (B’ − Y’)*224/256 + 128

where Y’ = 0.299 R’ + 0.587 G’ + 0.114 B’

The reverse formulas to convert YCbCr into RGB, 0 < =

RGB < = 255:

R’ = 1.164(Y601’ − 16) + 1.596(Cr’ − 128)

G’ = 1.164(Y601’ − 16) − 0.813(Cr’ − 128)

− 0.391(Cb’ − 128)

B’ = 1.164(Y601’ − 16) + 2.018(Cb’ − 128)

Y’U’V’

This conversion is BT 601 scaled to make YUV range

from 0 through 255. This setting is recommended for JPEG

encoding and is the most popular, although it is not well

defined and often misused in Windows.

Y’ = 0.299 R’ + 0.587 G’ + 0.114 B’

U’ = 0.564 (B’ − Y’) + 128

V’ = 0.713 (R’ − Y’) + 128

There is an option where 128 is not added to U’V’.

Y’Cb’Cr Using sRGB Formulas

The MT9D131 implements the sRGB standard. This

option provides YCbCr coefficients for a correct 4:2:2

transmission. Note that 16 < Y60 1< 235, 16 < Cb, Cr < 240

and 0 < = RGB < = 255.

Y’ = (0.2126*R’ + 0.7152*G’ + 0.0722*B’)*219/256

+ 16

Cb’ = 0.5389*(B ’− Y’)*224/256 + 128

Cr’ = 0.635*(R’ − Y’)*224/256 + 128

Y’U’V’ Using sRGB Formulas

Similar to the previous set of formulas, but has YUV

spanning a range of 0 through 255.

Y’ = 0.2126*R’ + 0.7152*G’ + 0.0722*B’

U’ = 0.5389*(B’ − Y’) + 128 = −0.1146*R’ − 0.3854*G’

+ 0.5*B’ + 128

V’ = 0.635*(R’ − Y’) + 128 = 0.5*R’ − 0.4542*G’

− 0.0458*B’ + 128

There is an option to disable adding 128 to U’V’. The

reverse transform is as follows:

R’ = Y + 1.5748*V

G’ = Y − 0.1873*(U − 128) − 0.4681*(V − 128)

B’ = Y + 1.8556*(U − 128)

MT9D131

www.onsemi.com

SENSOR CORE

This section describes the sensor core. The core is based

entirely on Micron’s MT9D011 sensor.

The SOC firmware controls a key sensor core registers,

such as exposure, window size, gains, and contexts. When

firmware or MCU are disabled, the sensor core can be

programmed directly.

Introduction

The sensor core is a progressive-scan sensor that

generates a stream of pixel data qualified by LINE_VALID

and FRAME_VALID signals. An on-chip PLL generates the

master clock from an input clock of 6 MHz to 40 MHz. In

default mode, the data rate (pixel clock) is the same as the

master clock frequency, which means that one pixel is

generated every master clock cycle. The sensor block

diagram is shown in Figure 13.

Figure 13. Sensor Core Block Diagram

Active−Pixel Sensor

(APS) Array

UXGA

1600H x 1200V

Control Register

Analog Processing ADC

Timing and Control

The core of the sensor is an active-pixel array. The timing

and control circuitry sequences through the rows of the

array, resetting and then reading each row. In the time

interval between resetting a row and reading that row, the

pixels in that row integrate incident light. The exposure is

controlled by varying the time interval between reset and

readout. After a row is read, the data from the columns is

sequenced through an analog signal chain (providing offset

correction and gain), and then through an ADC. The output

from the ADC is a 10-bit value for each pixel in the array.

The pixel array contains optically active and

light-shielded “black” pixels. The black pixels are used to

provide data for on-chip offset correction algorithms (black

level control).

The sensor contains a set of 16-bit control and status

registers that can be used to control many aspects of the

sensor operations. These registers can be accessed through

a two-wire serial interface. In this document, registers are

specified either by name (Column Start) or by register

address (R0x04:0). Fields within a register are specified by

bit or by bit range (R0x20:0[0] or R0x0B:0[13:0]). The

control and status registers are described in Table 4, “Sensor

Core Register Description”.

The output from the sensor is a Bayer pattern: alternate

rows are a sequence of either green/red pixels or blue/green

pixels. The offset and gain stages of the analog signal chain

provide per-color control of the pixel data.

Pixel Array Structure

The sensor core pixel array is configured as 1,688

columns by 1,256 rows (shown in Figure 14). The first 52

columns and the first and the last 20 rows of pixels are

optically black and are used for the automatic black level

adjustment. The last 4 columns are also optically black.

The optically active pixels are used as follows: In default

mode a UXGA image (1,600 columns by 1,200 rows) is

generated, starting at row 28, column 60. A 4-pixel

boundary of active pixels can be enabled around the image

to avoid boundary effects during color interpolation and

correction. During mirrored readout, the region of active

pixels used to generate the image is offset by 1 pixel in each

mirrored direction so that the readout always starts on the

same color pixel.

MT9D131

www.onsemi.com

Figure 14. Pixel Array

(1687, 1255)

52 black columns

20 black rows

20 black rows (0,0)

4 black columns

Oversize UXGA

1,632 x 1,216 active pixels

The sensor core uses a Bayer color pattern, as shown in

Figure 15. The even-numbered rows contain green and red

color pixels; odd-numbered rows contain blue and green

color pixels. Even-numbered columns contain green and

blue color pixels; odd-numbered columns contain red and

green color pixels. The color order is preserved during

mirrored readout.

Figure 15. Pixel Array

Black Pixels

Column Readout Direction

...

Direction

First Clear

Pixel

(52,20)

BG2

MT9D131

www.onsemi.com

Default Readout Order

By convention, the sensor core pixel array is shown with

pixel (0,0) in the top right corner (see Figure 15). This

reflects the actual layout of the array on the die. When the

sensor is imaging, the active surface of the sensor faces the

scene as shown in Figure 16. When the image is read out of

the sensor, it is read one row at a time, with the rows and

columns sequenced as shown in Figure 14. By convention,

data from the sensor is shown with the first pixel read

out−pixel (52,20) in the case of the sensor core−in the top left

corner.

Figure 16. Imaging a Scene

Lens

Pixel (0,0)

Row

Readout

O rder

Colum n Readout O rder

Scene

Sensor (rear view )

Raw Data Format

The sensor core image data is read out in a progressive

scan. Valid image data is surrounded by horizontal blanking

and vertical blanking as shown in Figure 17. The amount of

horizontal blanking and vertical blanking is programmable.

LINE_VALID is HIGH during the shaded region of the

figure. FRAME_VALID timing is described in the next

section.

Figure 17. Spatial Illustration of Image Readout

0,0

P0,1

P0,2 ................................P0,n−1P

0,n

1,0

P1,1

P1,2 ................................P

1,n−1P

1,n

00 00 00 ............. 00 00 00

m−1,0 Pm−1,1.........................Pm−1,n−1P

m−1,n

m,0 Pm,1.........................Pm,n−1Pm,n

00 00 00 ............. 00 00 00

00 00 00 ..................................... 00 00 00

00 00 00 ................................ 00 00 00

VALID IMAGE HORIZONTAL

BLANKING

VERTICAL BLANKING VERTICAL/HORIZONTAL

BLANKING

MT9D131

www.onsemi.com

Raw Data Timing

The sensor core output data is synchronized with the

PIXCLK output. When LINE_VALID is HIGH, one pixel

datum is output on the 10-bit DOUT output every PIXCLK

period. By default, the PIXCLK signal runs at the same

frequency as the master clock, and its rising edges occur

one-half of a master clock period after transitions on

LINE_VALID, FRAME_VALID, and DOUT (see

Figure 18). This allows PIXCLK to be used as a clock to

sample the data. PIXCLK is continuously enabled, even

during the blanking period. The sensor core can be

programmed to delay the PIXCLK edge relative to the DOUT

transitions from 0 to 3.5 master clocks, in steps of one-half

of a master clock. This can be achieved by programming the

corresponding bits in R0x0A:0. The parameters P, A, and Q

in Figure 19 are defined in Table 20.

Figure 18. Pixel Data Timing Example

0(9:0) P

1(9:0) P

2(9:0) P

3(9:0) P

4(9:0) P

n−1

(9:0) P

n(9:0)

Valid Image DataBlanking Blanking

LINE_VALID

PIXCLK

DOUT0−DOUT9

Figure 19. Row Timing and FRAME_VALID/LINE_VALID Signals

FRAME_

LINE_

VALID

PAQ AQAP

VALID

Number of master clocks

The sensor timing is shown in terms of pixel clock and

master clock cycles (see Figure 18). The recommended

master clock frequency is 36 MHz. Increasing the

integration time to more than one frame causes the frame

time to be extended. The equations in Table20 assume

integration time is less than the number of rows in a frame

(R0x09:0 < R0x03:0/S + BORDER + VBLANK_REG). If

this is not the case, the number of integration rows must be

used instead to determine the frame time, as shown in

Table 21.

TABLE 21. FRAME TIME

Parameter Name Equation

Default Timing

at 36 MHz Dual ADC Mode

HBLANK_REG Horizontal blanking

R0x07:0 if R0xF2:0[0] = 0

R0x05:0 if R0xF2:0[0] = 1

0x15C = 348 pixels

VBLANK_REG Vertical blanking register R0x8:0 if R0xF2:0[1] = 0

R0x6:0 if R0xF2:0[1] = 1

0x20 = 32 rows

ADC_MODE ADC mode R0xF2:0[3] = 0: R0x20:0[10]

R0xF2:0[3] = 1: R0x21:0[10]

PIXCLK_PERIOD Pixel clock period ADC_MODE = 0: R0x0A:0[2:0]

ADC_MODE = 1: R0x0A:0[2:0]*2

1 ADC_MODE: 55.556 ns

2 ADC_MODE: 27.778 ns

MT9D131

www.onsemi.com

TABLE 21. FRAME TIME (continued)

Parameter

Default Timing

at 36 MHz Dual ADC Mode

EquationName

SSkip factor For skip 2x mode: S = 2

For skip 4x mode: S = 4

For skip 8x mode: S = 8

For skip 16x mode: S = 16

otherwise, S = 1

AActive data time (R0x04:0/S) * PIXCLK_PERIOD 1,600 pixel clocks

= 1,600 master

= 44.44 μs

PFrame start/end

blanking

6 * PIXCLK_PERIOD

(can be controlled by R0x1F:0)

6 pixel clocks

= 12 master

= 0.166 μs

QHorizontal blanking HBLANK_REG * PIXCLK_PERIOD 348 pixel clocks

= 348 master

= 9.667 μs

A + Q Row time ((R0x04:0/S) + HBLANK_REG)

* PIXCLK_PERIOD

1,948 pixel clocks

= 1,948 master

= 54.112 μs

VVertical blanking VBLANK_REG * (A + Q) + (Q − 2*P) 62,672 pixel clocks

= 62,672 master

= 1.741 ms

Nrows * (A + Q) Frame valid time (R0x03:0/S) * (A + Q) − (Q − 2*P) 2,337,264 pixel clocks

= 2,337,264 master

= 64.925 ms

FTotal frame time ((R0x03:0/S) + VBLANK_REG) * (A + Q) 2,399,936 pixel clocks

= 2,399,936 master

= 66.665 ms

1. Skip factor should be multiplied by 2 if binning is enabled.

TABLE 22. FRAME − LONG INTEGRATION TIME

Parameter Name Equation (Master Clock)

V’ Vertical blanking (long integration time) (R0x09:0 – (R0x03:0)/S) * (A + Q) + (Q − 2*P)

F’ Total frame time (long integration time) (R0x09:0) * (A + Q)

Registers

Table 4, “Sensor Core Register Description,” provides a

detailed description of the registers. Bit fields that are not

identified in the table are read-only.

Double-Buffered Registers

Some sensor settings cannot be changed during frame

readout. For example, changing row width R0x03:0 part

way through frame readout results in inconsistent

LINE_VALID behavior. To avoid this, the sensor core

double-buffers many registers by implementing a “pending”

and a “live” version. READs and WRITEs access the

pending register. The live register controls the sensor

operation.

The value in the pending register is transferred to a live

start.” Frame start is defined as the point at which the first

dark row is read out. By default, this occurs 10 row times

before FRAME_VALID goes HIGH. R0x22:0 enables the

dark rows to be shown in the image, but this has no effect on

the position of frame start.

To determine which registers or register fields are

double-buffered in this way, see Table 4, “Sensor Core

R0x0D:0[15] can be used to inhibit transfers from the

pending to the live registers. This control bit should be used

when making many register changes that must take effect

simultaneously.

Bad Frames

A bad frame is a frame where all rows do not have the

same integration time, or where offsets to the pixel values

changed during the frame.

MT9D131

www.onsemi.com

Many changes to the sensor register settings can cause a

bad frame. For example, when row width R0x03:0 is

changed, the new register value does not affect sensor

behavior until the next frame start. However, the frame that

would be read out at that frame-start has been integrated

using the old row width. Consequently, reading it out using

the new row width results in a frame with an incorrect

integration time.

By default, most bad frames are masked: LINE_VALID

and FRAME_VALID are inhibited for these frames so that

the vertical blanking time between frames is extended by the

frame time.

To determine which register or register field changes can

produce a bad frame, see Table 4, “Sensor Core Register

Description,” the “bad frame” column, and these notations:

•N−No. Changing the register value does not produce a

bad frame

•Y−Yes. Changing the register value might produce a

bad frame

•YM−Yes; but the bad frame is masked out unless the

“show bad frames” feature (R0x0D:0[8]) is enabled

Changes to Integration Time

If the integration time (R0x09:0) is changed while

FRAME_VALID is asserted for frame n; the first frame

output using the new integration time is frame (n + 2). The

sequence is as follows:

1. During frame n, the new integration time is held in

the R0x09:0 pending register.

2. At the start of frame (n +1), the new integration

time is transferred to the R0x09:0 live register.

Integration for each row of frame (n + 1) has been

completed using the old integration time. The earliest time

that a row can start integrating using the new integration

time is immediately after that row has been read for frame

(n + 1). The actual time that rows start integrating using the

new integration time is dependent on the new value of the

integration time.

If the integration time is changed (R0x09:0 written) on

successive frames, each value written is applied to a single

frame; the latency between writing a value and it affecting

the frame readout remains at two frames.

Changes to Gain Settings

When the gain settings (R0x2B:0, R0x2C:0, R0x2D:0,

R0x2E:0, and R0x2F:0) are changed, the gain is usually

updated on the next frame start. When the integration time

and the gain are changed simultaneously, the gain update is

held off by one frame so that the first frame output with the

new integration time also has the new gain applied. All the

firmware drivers must be off (that is, seq.cmd = 0) before

manual control of gains or integration time (R0x09:0) is

possible.

MT9D131

www.onsemi.com

FEATURE DESCRIPTION

PLL Generated Master Clock

The PLL embedded in the sensor core can generate a

master clock signal whose frequency is up to 80 MHz (input

clock from 6 MHz through 64 MHz). Registers R0x66:0 and

R0x67:0 control the frequency of the PLL-generated clock.

It is possible to bypass the PLL and use EXTCLK as master

clock. To do so, one must set R0x65:0[15] to 1. If power

consumption is a concern, R0x65:0[14] should be also set to

1 a short time later, to put the bypassed PLL in power down

mode. To enable the PLL again, the two bits must be set to

0 in the reverse order. By default, the PLL is bypassed and

powered down.

PLL Setup

The PLL output frequency is determined by three

constants (M, N, and P) and the input clock frequency. These

three values are set in:

R0x66:0 // [15:8] for M; [5:0] for N

R0x67:0 // [6:0] for P

Their relations can be shown by the following equation:

fPLL, fOUT = fPLL, fIN, x M / [2 x (N+1) x (P+1)]

However, since the following requirements must be

satisfied, then not all combinations of M/N/P are valid:

M must be 16 or higher

fPFD, fVCO, fOUT ranges are satisfied

TABLE 23. FREQUENCY PARAMETERS

Frequency Equation Min (MHz) Max (MHz)

fPFD fIN / (N+1) 2 13

fVCO fPFD x M 110 240

fOUT fVCO / [2 x (P+1)] 6 80

fIN – 6 64

After determining the proper M, N, and P values and

setting them in R102:0/R103:0, the PLL can be enabled by

the following sequence:

R0x65:0[14] = 0 // powers on PLL

R0x65:0[15] = 0 // disable PLL bypass (enabling PLL)

NOTE: If PLL is used, bypass the PLL

(R0x65:0[15] = 1) before going into hard

standby. It can be enabled again

(R0x65:0[15] = 0) once the sensor is out of

standby.

PLL Power-up

The PLL takes time to power up. During this time, the

behavior of its output clock signal is not guaranteed. The

PLL is in the power-down mode by default and must be

turned on manually. When using the PLL, the correct

power-up sequence after chip reset is as follows:

1. Program PLL frequency settings (R0x66:0 and

R0x67:0)

2. Power up the PLL (R0x65:0[14] = 0)

3. Wait for a time longer than PLL locking time (>

1ms)

4. Turn off the PLL bypass (R0x65:0[15] = 0)

Window Control

Window Start

The row and column start address of the displayed image

can be set by R0x01:0 (row start) and R0x02:0 (column

start).

Window Size

The size of the sensor core image is controlled by R0x03:1

(Row Width) and R0x04:0 (column width). The default

image size is 1,600 columns and 1,200 rows (UXGA).

The window start and size registers can be used to change

the number of columns in the image from 17 through 1,632

and the number of rows from 2 through 1,216. The displayed

image size is controlled by the output and crop variables in

the mode (ID = 7) driver.

Pixel Border

When bits R0x20:0[9:8] are both set, a 4-pixel border is

added around the specified image. This border can be used

as extra pixels for image processing algorithms. The border

is independent of the readout mode, which means that even

in skip, zoom, and binning modes, a 4-pixel border is output

in the image. When enabled, the row and column widths are

8 pixels larger than the values programmed in R0x03:0 and

R0x04:0. If the border is enabled but not shown in the image

(R0x20[9:8] = 01), the horizontal blanking and vertical

blanking values are 8 pixels larger than the values

programmed in the blanking registers.

MT9D131

www.onsemi.com

Readout Modes

Readout Speeds and Power Savings

The sensor core has two ADCs to convert the pixel values

to digital data. Because the ADCs run at half the master

clock frequency, it is possible to achieve a data rate equal to

the master clock frequency. By turning off one of the ADCs,

the power consumption of the sensor is reduced. The pixel

clock is then reduced by a factor of two.

In R0x20:0 or R0x21:0, bit 10 chooses between the two

modes:

•0: Use both ADCs and read out at the set pixel clock

frequency (R0x0A:0[3:0])

•1: Use 1 ADC and read out at half the set pixel clock

frequency (R0x0A:0[3:0])

This can be used, for instance, when the camera is in

preview mode. To make the transitions between two sensor

settings easier, some simple context switching is described

in “Context Switching”.

Column Mirror Image

By setting R0x20:0[1] = 1 (R0x21:0 in context A), the

readout order of the columns are reversed as shown in

Figure 20. The starting color is preserved when mirroring

the columns.

Row Mirror Image

By setting R0x20:0[0] = 1 (R0x21:0 in context A), the

readout order of the rows are reversed as shown in Figure 21.

The starting color is preserved when mirroring the rows.

Figure 20. 6 Pixels in Normal and Column Mirror Readout Modes

LINE_VALID

Normal readout

(9:0)

DOUT0–DOUT9

Reverse readout

(9:0)

DOUT0–DOUT9

Figure 21. 6 Rows in Normal and Row Mirror Readout Modes

FRAME_VALID

Normal readout

Row0

(9:0)

Row1

(9:0)

Row2

(9:0)

Row3

(9:0)

Row4

(9:0)

Row5

(9:0)

Reverse readout

Row5

(9:0)

Row6

(9:0)

Row4

(9:0)

Row3

(9:0)

Row2

(9:0)

Row1

(9:0)

DOUT0–DOUT9

Column and Row Skip

This section assumes context B. If context A is used,

replace all references to R0x20:0 with R0x21:0.

By setting R0x20:0[4] = 1 or R0x20:0[7] = 1, skip is

enabled for rows or columns, respectively. When skip is

enabled, the image is subsampled. The amount of skipping

is set by R0x20:0[3:2] (rows) and R0x20:0[6:5] (columns)

according to Table 23. Depending on the skip value, the

output size variable in the mode (ID = 7) driver might need

adjustments.

TABLE 24. SKIP VALUE

Bit Values Skip Value

00 2

01 4

10 8

11 16

The number of rows or columns read out is what is set in

R0x03:0 or R0x04:0, respectively, divided by the skip value

in this table.

In all cases, the row and column sequencing ensures that

the Bayer pattern is preserved.

Column skip examples are shown in Figures 22 through

25.

MT9D131

www.onsemi.com

Figure 22. 8 Pixels in Normal and Column Skip 2x Readout Modes

LINE_VALID

Normal readout

(9:0)

LINE_VALID

Column skip readout

(9:0)

DOUT0–DOUT9

Figure 23. 16 Pixels in Normal and Column Skip 4x Readout Modes

DOUT0–DOUT9

LINE_VALID

Normal readout

(9:0)

LINE_VALID

Column skip readout

(9:0)

Figure 24. 32 Pixels in Normal and Column Skip 8x Readout Modes

DOUT0–DOUT9

LINE_VALID

Normal readout

(9:0)

G15

(9:0)

R15

(9:0)

LINE_VALID

Column skip readout

(9:0)

Figure 25. 64 Pixels in Normal and Column Skip 16x Readout Modes

DOUT0–DOUT9

LINE_VALID

Normal readout

(9:0)

G31

(9:0)

R31

(9:0)

LINE_VALID

Column skip readout

(9:0)

G16

(9:0)

R16

(9:0)

MT9D131

www.onsemi.com

Digital Zoom

Digital zoom is not used in SOC.

Binning

The sensor core supports 2 x 2 binning of 4 pixels of the

same color. This mode can be activated by asserting

R0x20:0[15] (R0x21:0 if context A is used).

Binning is primarily used instead of 2x skip as a way of

decimating the picture without losing information. The

effect of aliasing in preview mode is eliminated when

binning is used instead of just skipping rows and columns.

Activating binning has a few implications:

•It adds a level of skip, so the picture that comes out has

the same dimensions as a picture read out with the next

higher skip setting.

•It increases the minimum hblank and minimum row

time requirements (see Table 27 and Table 28).

TABLE 25. ROW ADDRESSING

Number of ADCs Binning

Row Addressing

(not considering start address)

1 No 0, 1, 2, 3, 4, 5, 6, 7,...

2 No 0, 1, 2, 3, 4, 5, 6, 7,...

1Yes 0/2, 1/3, 4/6, 5/7,...

2Yes 0/2, 1/3, 4/6, 5/7,...

TABLE 26. COLUMN ADDRESSING

Number of ADCs Binning

Row Addressing

(not considering start address)

1 No 0, 1, 2, 3, 4, 5, 6, 7,...

2 No 0/1, 2/3, 4/5, 6/7,...

1Yes 0/2, 1/3, 4/6, 5/7,...

2Yes 0/1/2/3, 4/5/6/7,...

Binning Limitations

To achieve correct operation, the following conditions

must be met:

•Start address must be divisible by four (row and

column).

•Window size must be divisible by four in both

directions, after dividing by zoom factor and skip factor

(because they both reduce the effective window size

from the sensor’s point of view).

Example: Default row size = 1,200. 8x zoom means the

actual window on the sensor is divided by 8, so 8x zoom and

binning is not allowed with default window size, because

1,200 / 8 = 150, which is not divisible by 4.

•Binning can be seen as an extra level of skip. The

combination binning/16x skip is therefore not legal.

Frame Rate Control

For a given window size, the blanking registers (R0x05:0

− R0x08:0) along with the row speed register (R0x0A:0) can

be used to set a particular frame rate.

The frame timing equations (Table 20 and Table 21 ) can

be rearranged to express the horizontal blanking or vertical

blanking values as a function of the frame rate:

HBLANK_REG = master clock freq / (frame rate * ((R0x03:0/S + BORDER) + VBLANK_REG)*PIXCLK_PERIOD)

− (R0x04:0/S + BORDER)

VBLANK_REG = master clock freq / (frame rate*(R0x04:0/S + BORDER) + HBLANK_REG)*PIXCLK_PERIOD)

− (R0x03:0/S + BORDER)

The HBLANK_REG value allows the frame rate to be

adjusted with a minimum resolution of one

PIXCLK_PERIOD multiplied by the total number of rows

(displayed plus blanking). When finer resolution is required,

R0x0B:0 (extra delay) can be used. R0x0B:0 allows the

frame time to be changed in increments of pixel clocks.

MT9D131

www.onsemi.com

Minimum Horizontal Blanking

The minimum horizontal blanking value is constrained by

the time used for sampling a row of pixels and the overhead

in the row readout. This is expressed in Table 26.

TABLE 27. MINIMUM HORIZONTAL BLANKING PARAMETERS

Parameter

Default / 2 ADC Mode,

No Binning

1 ADC Mode,

No Binning 2 ADC Mode, Binning 1 ADC Mode, Binning

HBLANK(MIN) 286 mclks 324 mclks = 162 pixclks 470 mclks 508 mclks = 254 pixclks

Minimum Row Time Requirement

The total row time must be sufficient to allow all row

operations (readout and shutter operations). The row time is

the sum of column width (halved during binning divided by

column skip factor) and horizontal blanking, and can

therefore be adjusted by programming these.

Table 28 shows minimum row time as a function of mode

of operation.

This is a particularly strict requirement during binning

because twice as many row operations are required per row

and the column width is halved.

TABLE 28. MINIMUM ROW TIME PARAMETERS

Parameter

Default / 2 ADC Mode,

No Binning

1 ADC Mode,

No Binning 2 ADC Mode, Binning 1 ADC Mode, Binning

ROW_TIME(MIN) 473 mclks 488 mclks = 244 pixclks 931 mclks 946 mclks = 473 pixclks

pointer_operations 461 mclks 464 mclks 919 mclks 922 mclks

Context Switching

When the sensor is in the SOC bypass mode, R0xF2:0 is

designed to enable easy switching between sensor modes.

Some key registers and bits in the sensor have two physical

R0xF2:0 control which context register context is currently

in use. A “1” in a bit selects context B, while a “0” selects

context A for this parameter. The select bits can be used in

any combination, but by default are set up to allow easy

switching between preview mode and full resolution mode:

TABLE 29. CONTEXT SWITCHING B

Context B (Default context)

R0xF2:0 = 0x000B (Context B)

R0x05:0 = 0x015C (Horizontal blanking, context B)

R0x06:0 = 0x0020 (Vertical Blanking, context B)

R0x20:0 = 0x0000 (2 ADCs, no column or row skip)

1. Description: Full resolution UXGA (1,600 x 1,200) image at 15 fps

TABLE 30. CONTEXT SWITCHING A

Context A (Alternate context, preview mode)

R0xF2:0 = 0x0000 (Context A)

R0x07:0 = 0x00AE (Horizontal blanking, context A)

R0x08:0 = 0x0010 (Vertical blanking, context A)

R0x21:0 = 0x0490 (1 ADC, 2x column and row skip)

1. Description: Half-resolution SVGA (800 x 600) image at 30 fps

The horizontal blanking and vertical blanking values for

the two contexts are chosen so that row time is preserved

between contexts. This ensures that changing contexts does

not affect integration time. See Table 5, “Sensor Core

Settings for skip, 1 ADC mode, and binning can be set

separately for context B and context A using R0x20:0 and

R0x21:0, respectively. When these settings are referred to in

this document, the register is dependent on what context is

set in R0xF2:0. For the default (no bypass) mode, context

switching is controlled by the sequencer (ID = 1) driver.

Integration Time

Integration time is controlled by R0x09:0 (shutter width

in multiples of the row time) and R0x0C:0 (shutter delay, in

PIXCLK_PERIOD/2). R0x0C:0 is used to control sub-row

integration times and only has a visible effect for small

values of R0x09:0. The total integration time, tINT, is shown

in the equation below:

MT9D131

www.onsemi.com

TABLE 31. TOTAL INTEGRATION TIME EQUATION (tINT)

tINT R0x09:0 * Row Time − Integration Overhead − Shutter Delay

Where:

Row time (R0x04:0/S + BORDER + HBLANK_REG)*PIXCLK_PERIOD master clock periods

SSkip Factor, multiplied by 2 if binning is enabled

Overhead time 260 master clock periods (262 in 1 ADC mode)

Shutter delay R0x0C:0 * PIXCLK_PERIOD master clock periods (2 in 1 ADC mode)

With Default Settings:

tINT (1,232 * (1,600 + 348)) − 260 − 0

2,399,676 master clock periods = 66.66ms at 36 MHz

In the equation, the integration overhead corresponds to

the delay between the row reset sequence and the row

sample (read) sequence.

Typically, the value of R0x09:0 is limited to the number

of rows per frame (which includes vertical blanking rows),

so that the frame rate is not affected by the integration time.

If R0x09:0 is increased beyond the total number of rows per

frame, the sensor adds blanking rows as needed.

Additionally, tINT must be adjusted to avoid banding in the

image caused by light flicker. Therefore, tINT must be a

multiple of 1/120 of a second under 60 Hz flicker, and a

multiple of 1/100 of a second under 50 Hz flicker.

Maximum Shutter Delay

The shutter delay can be used to reduce the integration

time. A programmed value of N reduces the integration time

by N master clock periods. The maximum shutter delay is set

by the row time and the sample time, as shown in the

equation below:

TABLE 32. MAXIMUM SHUTTER DELAY EQUATION (tINT)

Maximum shutter delay (Row Time − pointer_operations)

Where:

Row time (R0x04:0/S + BORDER + HBLANK_REG)*PIXCLK_PERIOD master clock periods

SSkip Factor, multiplied by 2 if binning is enabled

pointer_operations See table 28

With Default Settings:

Maximum shutter delay (1,600 + 348) − 461

1,487 (master clock periods)

If the value in this register exceeds the maximum value

given by this equation, the sensor may not generate an

image.

Analog Signal Path

The sensor core features two identical analog readout

channels. A block diagram for one channel is shown in

Figure 26. The readout channel consists of two gain stages

(ASC1 and ASC2), a sample-and-hold (ADCSH) stage with

black level calibration capability (VOFFSET), and a 10−bit

ADC.

Figure 26. Analog Readout Channel

ASC1 ASC2 ADCSH 10-bit

(G1) (G2) (G3) ADC

V1 V2 V3

Vpix ADC_code

VOFFSET VREFD

MT9D131

www.onsemi.com

Stage-by-Stage Transfer Functions

Transfer functions proceed stage-by-stage, as follows:

TABLE 33. STAGE-BY-STAGE TRANSFER FUNCTIONS

Let VPIX be the input of the signal path: VPIX = pixel output voltage = signal path input voltage

The output voltage of ASC 1st stage is: V1 = −1*G1*VPIX (1)

The output voltage of ASC 2nd stage is: V2 = −1*G2*V1 (2)

The output voltage of ADC Sample-and-Hold stage is: V3 = 2*G3*V2 − VREFD + VOFFSET (3)

and the ADC output code is: ADC output code = 511*(1 + (V3 / VrEFD)) (4)

From (1) to (4), the ADC output code can also be written as: ADC code = (1022/VREFD)*[G1*G2*G3*VPIX +

(Voffset/(2*G3))]

(5)

Where G1, G2, and G3 are the gain settings, VOFFSET is

the offset (calibration) voltage, and VREFD is the reference

voltage of the ADC. The gain setting G3 is applied to the

signal but is not applied to VOFFSET. The parameters

VREFD, G1, G2, G3, and VOFFSET are described next.

VREFD

The VREFD parameters are as follows:

TABLE 34. VREFD PARAMETERS

The ADC reference voltage VREFD Is: VREFD = VREF_HI − VREF_LO (6)

where VREF_HI = 55.5mV*(R0x41:0[7:4] + 23) (7)

using default register values: VREF_HI = 55.5mV*(13 + 23) = 1.998V

and VREF_LO = 55.5mV*(R0x41:0[3:0] +11) (8)

using default register values: VREF_LO = 55.5mV*(7 +11) = 0.999V

so VREFD = 55.5mV*(R0x41:0[7:4] − R0x41:0[3:0] + 12) (9)

using default register values VREFD = 1.998 − 0.999 = 0.999V

Analog Gain Settings: G1, G2, G3

The analog gains for green1, blue, red, and green2 pixels

(as shown in Figure 26) are set by registers R0x2B:0,

R0x2C:0, R0x2D:0, and R0x2E:0, respectively. Gain can

also be globally set by R0x2F:0. The analog gain is set by

bits 8:0 of the corresponding register as follows:

G1 = bit 7 + 1 (10)

G2 = bit 6:0 / 32 (11)

G3 = bit 8 + 1 (12)

Digital gain is set by bits 11:9 of the same registers.

Offset Voltage: VOFFSET

The offset voltage provides a constant offset to the ADC

to fully utilize the ADC input dynamic range. The offset

voltages for green1, blue, red, and green2 pixels are

manually set by registers R0x61:0, R0x62:0, R0x63:0, and

R0x64:0, respectively. The offset voltages also can be

automatically set by the black level calibration loop.

For a given color, the offset voltage, VOFFSET, is

determined by:

TABLE 35. OFFSET VOLTAGE (VOFFSET)

VOFFSET = 0.50 V*offset_gain*offset_sign*offset_code[7:0]/2557 (13)

where: “offset_sign” is determined by bit 8 as:

if bit 8 = 0, offset_sign = +1 (14)

if bit 8 = 1, offset_sign = −1(15)

“offset_code” is the decimal value of bit<7:0>

OFFSET_GAIN is determined by the 2-bit code from

R0x5A:0[1:0], as shown in Table 36. These step sizes are

not exact; increasing the stage0 ADC gain from 2 to 4

decreases the step size significance; decreasing the ADC

VREFD increases the step size significance.

MT9D131

www.onsemi.com

TABLE 36. OFFSET GAIN

R0x5A:0[1:0] OFFSET_GAIN

00 OFFSET_GAIN = 0 (no calibration voltage is applied)

01 OFFSET_GAIN = 0.25 (1 calibration LSB is equal to 0.5 ADC LSB when VREFD = 1 V)

10 OFFSET_GAIN = 0.50 (1 calibration LSB is equal to 1 ADC LSB when VREFD = 1 V)

11 OFFSET_GAIN = 1 (1 calibration LSB is equal to 2 ADC LSB when VREFD = 1 V)

Recommended Gain Settings

The analog gain circuitry in the sensor core provides

signal gains from 1 through 15.875.

TABLE 37. RECOMMENDED GAIN SETTINGS

Desired Gain Recommended Gain Register Setting

1–1.969 0x020–0x03F

2–7.938 0x0A0–0x0FF

8–15.875 0x1C0–0x1FF

MT9D131

www.onsemi.com

FIRMWARE

Firmware implements all automatic functionality of the

camera, including auto exposure, white balance, flicker

detection and so on. The firmware consists of drivers,

generally one driver for each major control function. The

firmware runs on a 6811-compatible microcontroller with a

mathematical coprocessor.

Overview of Architecture

Bootstrap Routine

The firmware consists of a bootstrap code, drivers, and a

test module. The bootstrap code initializes internal

low-level MCU registers, performs a mini-self-test, and sets

up a 128-bytes deep stack. The main routine is then invoked.

Drivers

Firmware applications are organized into drivers. Each

driver performs a specific function. Each driver has its own

data structure with various variables. The user can access the

data structure through R0xC6:1 and R0xC8:1 to read or

write variables. The access is implemented using hardware

direct memory access (DMA). Drivers are static objects with

virtual methods. Each driver has an associated data structure

and a driver ID. To access driver variable, the user must

know driver ID and variable offset in the data structure.

Drivers are static objects with virtual methods. Each

driver has an associated data structure and a driver ID. To

access a driver variable, the user must know driver ID and

variable offset in the data structure.

Figure 27. Sequencer Driver

Leave

Preview

Ch.Mode

To Capture

Capture

Standby

Do Standby

Refresh IFP

Run

Enter

Capture

Leave

Capture

Do Preview

Do Capture

Ch.Mode

To Preview

Enter

Preview

Refresh Sensor

Run

Do Preview

Init

Lock

Do Preview

Do Capture

Lock

Preview

Sequencer Driver

The sequencer is a finite state machine that controls the

operation of main functions and the switching between

modes. Camera operation is organized as states, such as

preview or capture. The sequencer carries out a number of

programs, such as previewing, preview lock, capture, and so

on.

The state of the sequencer is indicated in variable state. To

have the sequencer execute a certain program, set the

MT9D131

www.onsemi.com

program number in cmd. The host then should monitor state

to know when to change resolution and/or capture frames.

Each state has its configuration (see

”Firmware Driver Variables”). Before executing programs,

set up state configurations to customize the program. For

example, to capture compressed frames, enable

compression in capture state configuration.

A typical scenario includes the following:

1. Configure mode variables after hardware reset.

−Set up sensor image size for preview.

−Set up displayed image size.

−Set up FIFO to smooth data rate.

2. Configure preview mode.

−Set auto exposure, white balance speed.

3. Execute sensor REFRESH command.

4. Run in preview until shutter button is depressed.

−If the shutter button is depressed halfway,

execute the lock program.

aConfigure preview state to disable

necessary functions to be locked, for

example, auto exposure, and white

balance.

bConfigure PreviewLeave state for fast

settling of those functions.

cExecute the lock program.

dThe lock program transits PreviewLeave

state, perform fast settling, and return to

Preview state, which was configured to

freeze (lock).

−If the shutter button is depressed all the way,

execute the capture program.

aIf already in lock mode, disable

PreviewLeave state and execute capture

program.

bIf not in lock state and some settling is

required, configure PreviewLeave state

for fast settling.

cExecute capture program. The program

transitions to PreviewLeave, perform

required settling and proceed through

mode change to capture.

5. Capture a frame.

−Preconfigure capture mode variables for

correct image size, compression, and select

video/still.

−Monitor the “state” variable. When the state is

capture, grab the frame(s).

Optionally, configure Capture Enter or Preview Leave to

have output blanked. This helps grabbing correct frame for

capture.

Low-Light Operation

A number features are available to improve image quality

in low-light conditions:

•Increased noise suppression in interpolation

•Reduced color saturation

•Reduced aperture correction

•Increased aperture correction threshold

•Y-filter

The seq.sharedParams.LLmode variable enables

individual low-light features. seq.sharedParams.LLv

irtGain1 and 2 specify gain thresholds to enable some of

these features. Values are given by seq.sharedParams.LLI

nterpThresh1/2, LLSat1/2, LLApCorr1/2, and LLApThres

h1/22.

Auto Exposure Driver

The AE driver works to achieve desirable exposure by

adjusting sensor core’s integration time, analog, and digital

gains. The driver can be configured with respect to desired

AE speed, maximum and minimum frame rate, the range of

gains, brightness, backlight compensation, and so on.

AE driver typically runs in one of these modes. The modes

are set in the sequencer driver for each sequencer state.

•Fast settling preview−reach target exposure as fast as

possible

•Continuous preview−a slow-changing mode good for

video capture

•Evaluative−evaluate current scene and adjust exposure

for still capture

Some key variables affecting all modes:

•ae.Target−controls target exposure for all modes.

Increasing or decreasing this variable makes the image

brighter or darker

•ae.Gate−how accurate AE driver tracks the target

exposure

•ae.weights−specify weights for central and peripheral

backlight compensation in preview modes

AE driver adjusts exposure by programming sensor gains,

R0x2B–R0x2E:0 and R0x41:0, sensor integration time

R0x9:0 and R0xC:0 and IFP digital gains R0x4E:2 and

R0x6E:1.

Evaluative Auto Exposure

Evaluative AE (EAE) selects optimum exposure for

scenes where conventional AE does

not give good results:

•Scenes involving sun

•Back light scenes

•Strong contrast scenes and so on

MT9D131

www.onsemi.com

EAE breaks down input image into a 4 x 4 grid of

subwindows and analyzes their exposure value (EV)

readings. It evaluates brightness and contrast in the image,

the scene and adjusts exposure appropriately. Variables

ae.mmEVZone1/2/3/4 keep programmable thresholds

defining brightness classes. Variable ae.mmShiftEV is used

to calibrate EV readings for particular module type.

Mode Driver

The mode driver reduces integration efforts by managing

most aspects of switching between preview (mode A) and

capture (mode B) modes. It remembers vital register values

for each image acquisition mode and uploads these values to

the appropriate registers upon each mode switch. In addition

to remembering the register data, it also creates preloaded

and custom gamma and contrast tables for each mode.

To change the mode driver parameters, upload the new

values to the mode driver table (ID = 7). Upon the next mode

change or sequencer REFRESH (CM_REFRESH)

command, these mode driver values are uploaded to the

appropriate sensor and system registers, and the image

processing then reflects the new values (at the beginning of

the next frame acquired).

To control the output image size, upload the dimensions

to the mode driver variables: output width_A, output

height_A, output width_B and output height_B. The mode

driver automatically applies any appropriate downsizing

filter to achieve this output image size as well as updating the

FIFO output size when in JPG bypass (RAW) mode. It is

important so set up the imager to output an image equal to

or larger than the target output image. It is also important for

the crop window (crop_left_A/B and crop_right_A/B) to be

equal to or larger than the target output image.

To upload a custom gamma table, upload the values to the

appropriate mode driver locations (see Table 16, “Driver

Variables−JPEG Driver (ID = 9)”), and select “3”

(user-defined) for the gamma table type for the particular

mode. If a contrast level is selected, it is applied to the

user-uploaded gamma table.

The driver contains settings for raw and output image size

and pan for each mode. See variables such as

mode.sensor_col_width_A/B,

mode.sensor_row_height_A/B and mode.fifo_width_A/B,

mode.fifo_height_A/B. Blanking and readout mode− the

use of skip, binning, and 1ADC modes− is configured using

sensor core registers

R0x5:1–R0x8:1 and R0x20:1, R0x21:1.

To change overall image brightness by changing adding

luma offset at output, set

•mode.y_rgb_offset_A for preview

•mode.y_rgb_offset_B for capture

To change output format, set

•mode.output_format_A for preview

•mode.output_format_B for capture

Similarly, the user can set special effects for each mode

using mode.spec_effects_A/B.

JPEG Driver

The JPEG driver programs Huffman table and

quantization table memories, sets up the MT9D131 to output

JPEG compressed data, and handles error checking and

handshaking with the host processor.

Usage

JPEG is enabled using mode.mode_config. For example,

to enable compression for capture set mode.mode_congif =

16. jpeg.qscale1/2/3, and specify the quantization factor to

control compression ratio. Bigger number indicates more

compression. mode.fifo* configure spoof and non-spoof

output and specify FIFO output clock divider. If necessary,

use jpeg.config for error handshaking with the host.

Table Programming

At power-up initialization, the JPEG driver loads standard

Huffman tables into Huffman memory. Scaled versions of

standard luma and chroma quantization tables and are

loaded into quantization memory. The calculation of the

scaled quantization table is as follows:

Scaled_Q = (scaling_factor * standard_Q + 16) >> 5

Scaling factor is bit 6:0 of JPEG driver variables qscale1,

qscale2, and qscale3. The standard quantization and

Huffman tables are Tables K.1–K.4 of the ISO/IEC 10918−1

Specification. Host processor can override Huffman and

quantization memory with any arbitrary Huffman and

quantization tables through indirect register access.

If the host chooses to use the scaled standard quantization

tables, bit 4 of JPEG driver variable config must be set to

“1.” Scaling factor can be changed at any time. Whenever it

is changed, bit 7 of the corresponding JPEG driver variable

qscale must be set to “1,” and the new value takes effect in

the next frame JPEG encoding.

Since the quantization memory stores three sets (with

luma and chroma information) of quantization tables, the

one that is used for the current frame JPEG encoding is

indicated in bit 7:6 of jpeg.config (quantization table ID).

Bit 5 of jpeg.config determines who is responsible for

setting the quantization table ID. If it is “0,” the host

processor must program quantization table ID for every

JPEG compressed frame (no need to reprogram it if

subsequent JPEG frames use the same quantization tables).

If it is “1,” the JEPG driver sets quantization table ID to “0”

at the start of JPEG capture (be it still or video) and

automatically select next set of quantization tables for the

subsequent frames when the current JPEG frame is

unsuccessful.

Bit 7:6 of jpeg.config = 0, 1, and 2 indicates first, second,

and third set of quantization tables, respectively.

MT9D131

www.onsemi.com

Error Handling and Handshaking

When the capturing of a JPEG snapshot is unsuccessful,

the JPEG driver can be configured to enable encoding

subsequent frames until it is successful by setting bit 2 of

jpeg.config to “1.” For capturing JPEG video, MT9D131

always encodes subsequent frames no matter what value bit

2 of jpeg.config is set to.

If bit 1 of jpeg.config is “1,” handshaking with the host

processor at every erroneous JPEG frame is required. When

JPEG status register indicates that there is an error in the

current JPEG frame, JPEG encoding is stopped until the host

processor sets bit 3 of jpeg.config to “1” to indicate it is

ready to receive next JPEG frame. If the host processor does

not respond to an erroneous JPEG frame within

jpeg.timeoutFrames frames, JPEG capture is terminated. If

bit 1 of jpeg.config is “0” or if there is no error in JPEG status

The handshaking mechanism is provided so that the host

processor has sufficient time to handle the erroneous JPEG

frame and react upon the error condition. For example, if the

JPEG status register indicates FIFO overflow, the host

processor should increase quantization value by changing

quantization table scaling factor or selecting another set of

the preloaded quantization tables. If spoof oversize error

occurs, the host processor should increase the spoof frame

size by programming registers R0x10 and R0x11 on IFP

MT9D131

www.onsemi.com

START-UP AND USAGE

The start-up sequence consists of the following:

1. Power-up

2. Hardware reset

3. Configure and enable PLL

4. Configure pad slew rate

5. Configure preview mode

6. Configure capture mode

7. Perform lock or capture

To start the part, power up power supplies, provide an

input clock, and perform a hardware reset.

Power-Up

There are no specific requirements to the order in which

different supplies are turned on. Once the last supply is

stable within the valid ranges specified below, follow the

hard reset sequence to complete the power-up sequence. To

minimize leakage current, all the power supplies should be

turned on at the same time:

•Analog Voltage: 2.8 V for best image performance

•Digital Voltage: 1.8 V +0.1 V (1.7 V–1.9 V)

•I/O Voltage: 1.7 V–3.1 V

Power-Down

Before powering down the sensor, it is recommended to

bypass the PLL. Once this is completed, the input clock

(EXTCLK) can be turned off. After EXTCLK is off, turn off

all the power supplies as shown in Figure 28. RESET_BAR

should also be LOW at this time.

NOTE:Turning the power supplies off cannot be used as a

method of achieving low power consumption.

Power to the sensor needs to be provided as long

as the system is active. For the lowest power

consumption, refer to the standby procedure.

Hard Reset Sequence

After power-up, a hard reset is required. Assuming all

supplies are stable, the assertion of RESET_BAR (active

LOW) sets the device in reset mode. The clock is required

to be active when RESET_BAR is released. Hence, leaving

the input clock running during the reset duration is

recommended. After 24 clock cycles (EXTCLK), the

two-wire serial interface is ready to accept commands. Reset

should not be activated while STANDBY is asserted.

A hard reset sequence to the camera can be activated by

the following steps:

1. Wait for all power supplies to be stable and within

specification.

2. Supply the sensor with an input clock.

3. Assert RESET_BAR (active LOW) for at least

1μs.

4. De-assert RESET_BAR

5. Wait 24 clock cycles before using the two-wire

serial interface.

Refer to Figure 28 for the timing diagram.

Figure 28. Power On/Off Sequence

VDD, VDDQ,

VAA, VAAPIX

RESET#

EXTCLK

SCLK/SDATA (SHIP)

STANDBY

24−EXTCLK

INACTIVE

POWER

DOWN

POWER UP

RESET (>1s)

1. For a safe RESET to occur, EXTCLK should be running during RESET with STANDBY LOW, as shown in the sequence above.

2. After RESET_BAR is HIGH, wait 24 EXTCLK rising edges before the two-wire serial interface communication is initiated.

3. After the power-up sequence, the preview state is reached when the firmware variable seq.state (ID = 1, Offset = 4) is equal to 3. This

transition time varies depending on the input clock frequency and scene conditions.

4. To go into the firmware standby state, go to capture mode (also known as context B), or execute the firmware REFRESH/REFRESH_MODE

commands after the power-up sequence (the preview state [seq.state = 3] must be reached first).

MT9D131

www.onsemi.com

Soft Reset Sequence

A soft reset to the camera can be activated by the

following procedure:

1. Bypass the PLL, R0x65:0 = 0xA000, if it is

currently used

2. Perform MCU reset by setting R0xC3:1 = 0x0501

3. Enable soft reset by setting R0x0D:0 = 0x0021.

Bit 0 is used for the sensor core reset while bit 5

refers to SOC reset.

4. Disable soft reset by setting R0x0D:0 = 0x0000

5. Wait 24 clock cycles before using the two-wire

serial interface

NOTE:No access to MT9D131 registers−both page1 and

page 2-is possible during soft reset.

Enable PLL

Since the input clock frequency is unknown, the part starts

with PLL disabled. The default MNP values are for 10 MHz,

with 80 MHz as target. For other frequencies, calculate and

program appropriate M, N, and P values. PLL programming

and power-up sequence is as follows:

1. Program PLL frequency settings, R0x66–R0x67:0

2. Power up PLL, R0x65:0[14] = 0

3. Wait for PLL settling time >150μs

4. Turn off PLL bypass, R0x65:2[15] = 0

Allow one complete frame to effect the correct integration

time after enabling PLL.

NOTE: Until PLL is enabled the two-wire serial

interface may be limited in speed. After PLL is

enabled, the two-wire serial interface master can

increase its communication speed.

Configure Pad Slew

Program the desired slew rate for DOUT, PIXCLK,

FRAME_VALID, and LINE_VALID at the variables,

mode.fifo_conf1/2_A/B. Program R0xA:1 with desired

slew rate for two-wire serial interface SDATA and SCLK.

Configure Preview Mode

The default preview image size is 800 x 600, running at up

to 30 fps at 80 MHz internal clock. To change the default

size, program mode driver variables mode.output_width_A

and mode.output_height_A and issue a REFRESH

command, seq.cmd = 5.

For example, to configure 160x120 LCD RGB preview,

program

•mode.output_width_A = 160

•mode.output_width_B = 120

•mode.out_format_A = 0x20

•seq.cmd = 5

Preview contrast, brightness, gamma, frame rate, and

many other parameters can be loaded here as well. If known

at this time, the user can also program capture parameters.

If necessary, set up the AE/WB lock command here.

Configure Capture Mode

Program the mode and other drivers, when desired capture

parameters (video, still, compression, and resolution) are

known.

Perform Lock or Capture

See ”Sequencer Driver” for details.

Standby Sequence

Standby mode can be activated by two methods. The first

method is to assert STANDBY, which places the chip into

hard standby. Turning off the input clock (EXTCLK)

reduces the standby power consumption to the maximum

specification of 100μA at 55_C. There is no serial interface

access for hard standby.

The second method is activated through the serial

interface by setting R0xD:0[2] = 1 to the register, known as

the soft standby. As long as the input clock remains on, the

chip allows access through the serial interface in soft

standby.

Standby should only be activated from the preview mode

(context A), and not the capture mode (context B). In

addition, the PLL state (off/bypassed/activated) is recorded

at the time of firmware standby (seq.cmd = 3) and restored

once the camera is out of firmware standby. In both hard and

soft standby scenarios, internal clocks are turned off and the

analog circuitry is put into a low power state. Exit from

standby must go through the same interface as entry to

standby. If the input clock is turned off, the clock must be

restarted before leaving standby. If the PLL is used to

generate the master clock, ensure that the PLL is powered

down during standby because it uses a relatively high

amount of power. By default, R0x65:0[13] powers down the

PLL when the chip enters standby mode. Turn on the PLL

bypass (R0x65:0[15] = 1) to prepare the PLL for standby.

To Enter Standby

1. Preparing for standby

−Issue the STANDBY command to the

firmware by setting seq.cmd = 3

−Poll seq.state until the current state is in

standby (seq.state = 9)

−Bypass the PLL if used by setting

R0x65:0[15] = 1

2. Preventing additional leakage current during

standby

−Set R0xA:1[7] = 1 to prevent elevated standby

current. It controls the bidirectional pads

DOUT, LINE_VALID, FRAME_VALID, and

PIXCLK.

−If the outputs are allowed to be left in an

unknown state while in standby, the current

can increase. Therefore, either have the

receiver hold the camera outputs HIGH or

LOW, or allow the camera to drives its

MT9D131

www.onsemi.com

outputs to a known state by setting R0xD:0[6]

= 1, R0xD:0[4] needs to remain at the default

value of “0.” In this case, some pads are

HIGH while some are LOW. For dual camera

systems, at least one camera has to be driving

the bus at any time so that the outputs are not

left floating.

3. Putting the camera in standby

−Assert STANDBY = 1. Optionally, stop the

EXTCLK clock to minimize the standby

current specified in the MT9D131 data sheet.

For soft standby, program standby R0xD:0[2]

= 1 instead.

To Exit Standby

1. De−assert standby

−Provide EXTCLK clock, if it was disabled

when using STANDBY

−De-assert STANDBY = 0 if hard standby was

used. Or program R0xD:0[2] = 0 if soft

standby was used

2. Reconfiguring output pads

3. Issue a GO_PREVIEW command to the firmware

by setting seq.cmd = 1

4. Poll seq.state until the current state is preview

(seq.state = 3)

The following timing requirements should be met to turn

off EXTCLK during hard standby:

1. After asserting standby, wait 1 row time before

stopping the clock

2. Restart the clock 24 clock cycles before

de-asserting standby

Figure 29. Hard Standby Sequence

Power Up

Sequence

Completed

VDD, VDDQ,

VAA, VAAPIX

RESET#

EXTCLK

SCLK/SDATA (SHIP)

STANDBY

When seq.state=3,

the sensor is back

in active state

Wait for

seq.state=9,

then bypass

PLL and set

all the

required

registers/

variables

described Assert

STDBY

EXTCLK

off EXTCLK

Reconfig

pads if necessary,

then call

seq.cmd=1

Wait for

seq.state=3,

then call

seq.cmd=3

De−

assert

STDBY

1 row−time 24−EXTCLK

Low Power

State

output

Standby Hardware Configuration

While in standby, floating IO signals may cause the

standby current to rise significantly. Therefore, it is

recommended that the following signals be maintained

HIGH or LOW during standby and not floating: DOUT[7:0],

PIXCLK, FRAME_VALID, and LINE_VALID.

Output Enable Control

When the sensor is configured to operate in default mode,

the DOUT, FRAME_VALID, LINE_VALID, and PIXCLK

outputs can be placed in High-Z under hardware or software

control, as shown in Table 38.

MT9D131

www.onsemi.com

TABLE 38. OUTPUT ENABLE CONTROL

Standby R0x0D:0[4] (output_dis) R0x0D:0[6] (drive_pins) Output State

00 (default) 0 (default) Driven

10 (default) 0 (default) High−Z

“Don’t Care” 0 (default) 1 Driven

“Don’t Care” 1“Don’t Care” High−Z

The pin transition between driven and High-Z always

occurs asynchronously. Output-enable control is provided

as a mechanism to allow multiple sensors to share a single

set of interface pins with a host controller.

There is no benefit in placing the pins in a High-Z while

the part is in its low-power standby state. Therefore, in

single-sensor applications that use STANDBY to enter and

leave the standby state, programming R0x0D:0[6] = 1 is

recommended.

Contrast and Gamma Settings

The MT9D131 IFP includes a block for gamma and

contrast correction. A custom gamma/contrast correction

table may be uploaded, or pre-set gamma and contrast

settings may be selected.

The gamma and contrast correction block uses the

following 12-bit input data points to form a piecewise linear

transformation curve: 0, 64, 128, 256, 512, 768, 1024, 1280,

1536, 1792, 2048, 2304, 2560, 2816, 3072, 3328, 3584,

3840, and 4095. These input points have been selected to

provide more detail to the low end of the curve where

gamma correction changes are typically the greatest. These

points correspond to 8-bit output values that can be uploaded

to the appropriate registers.

Figure 30. Gamma Correction Curve

Gamma Correction

100

150

200

250

300

0 1000 2000 3000 4000

Input RGB, 12−bit

Output RGB, 8−bit

0.45

For simplicity, predefined gamma and contrast tables may

be selected, and the MT9D131 automatically combines

these tables and upload them to the appropriate gamma

correction registers.

The gamma and contrast tables may be selected at mode

driver (ID = 7) offsets 67 and 68 (decimal) for mode A and

mode B, respectively. The gamma settings are established at

bits 0–2, and the contrast settings are established at bits 4–6.

The gamma setting values are shown in Table 39.

TABLE 39. GAMMA SETTINGS

Gamma Setting Definition

0Gamma = 1.0 (no gamma correction)

1Gamma = 0.56

2Gamma = 0.45

3Use user-defined gamma table

MT9D131

www.onsemi.com

S-Curve

The predefined contrast table values have been

established by creating an ”S” curve with highlight and

shadow regions that blend smoothly with a linear midtone

region. The slope and value of the highlight and shadow

regions match the linear region at these transitions. In

addition, the slope of the ”S” curve is zero at the top (white)

and bottom (black) points. The slope of the linear region

determines how much contrast is applied; more contrast

corresponds to a higher, midtone linear slope.

Figure 31. Contrast “S” Curve

The contrast values are shown in Table 40.

TABLE 40. CONTRAST VALUES

Contrast Setting Definition

0No contrast correction

1Contrast slope = 1.25

2Contrast slope = 1.50

3Contrast slope = 1.75

4Noise reduction contrast

The contrast curve function is applied to the gamma curve

points used (whether the gamma curve points are predefined

or user-uploaded).

S-curve is a function to correct image pixel values. When

applied to pixel values, it typically compresses dark and

bright tones, while stretching the midtones. Figure 32 shows

how input tone range is remapped to output tone range.

Categorize input pixel values as dark, midlevel, and bright.

When no S-curve is applied, pixel values are unchanged.

That is, dark tones 0...x1 map to same dark tones 0...x1=y

and midlevel maps to identical midlevel x1= x

2, and bright

maps to identical bright. When an S-curve is applied, the

mapping is changed. In particular, midtones are stretched

(y1 – y2)>(x

1 – x2), causing increase of contrast. Here

(y1 – y2)/(x

1 – x2) is a measure of contrast. Value of 1

corresponds to no change; >1 and <1 indicate contrast

increase and decrease, respectively. Dark tones are

compressed, y1<x

1, causing suppression of noise.

MT9D131

www.onsemi.com

Figure 32. Tonal Mapping

x1x2

Dark Mid Bright

Input Input

OutputOutput

Dark Mid Bright

The contrast settings on the MT9D131 are implemented

by applying an S-curve function on to the data points of the

gamma curve. These resulting points then replace the

existing gamma curve points, and the image is processed

using this new contrast-enhanced gamma curve. Identical

S-curve is applied to all three RGB components.

The S-curve is created by joining a linear midsection

(often with a slope greater than one) to curved sections for

highlights and shadows. The following constraints apply to

the overall curve to ensure a smooth curve appropriate for

increased contrast:

1. The first/lowest point must be (0,0) and the

last/highest point must be (1,1) (normalized).

2. The midsection and each of the end-curves must

intersect on the same points.

3. The slope of the midsection and each of the

end-curves must be equal at the intersection

points.

The midsections a simple linear function of the form:

y = mx + b. Each of the end-curves (shadow and highlights)

must be a trinomial to satisfy all boundary conditions.

Figure 33. Contrast Diagram

Contrast Only

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Highlight

Region

Linear Mid

Tone Region

Shadow

Region

(x 1,y 1)

(x 2,y 2)

MT9D131

www.onsemi.com

Auto Exposure

Two types of auto exposure are available−preview and

evaluative.

Preview

In preview AE, the driver calculates image brightness

based on average luma values received from 16

programmable equal-size rectangular windows forming a 4

x 4 grid. In preview mode, 16 windows are combined in 2

segments: central and peripheral. Central segment includes

four central windows. All remaining windows belong to

peripheral segment. Scene brightness is calculated as

average luma in each segment taken with certain weights.

Variable ae.weights[3:0] specifies central zone weight,

ae.weights[7:4] - peripheral zone weight.

The driver changes AE parameters (IT, Gains, and so on)

to drive brightness (ae.CurrentY) to programmable target

(ae.Target). Value of one step approach to target is defined

by ae.JumpDivisor variable. Expected brightness is

Ynew = ae.CurrentY+(ae.Target-ae.CurrentY)/ae.Jump

Divisor.

To avoid unwanted reaction of AE on small fluctuations

of scene brightness or momentary scene changes, the AE

driver uses temporal filter for luma and gate around AE luma

target. The driver changes AE parameters only if buffered

luma outsteps AE target gates. Variable

ae.lumaBufferSpeed defines buffering level.

32*Ybuf1 = Ybuf0*(32-ae.lumaBufferSpeed)+Ycurr*

ae.lumaBufferSpeed;

Values ae.lumaBufferSpeed = 32 and ae.JumpDivisor = 1

specify maximal AE speed.

Evaluative Algorithm

A scene evaluative AE algorithm is available for use in

snapshot mode. The algorithm performs scene analysis and

classification with respect to its brightness, contrast, and

composure and then decides to increase, decrease, or keep

original exposure target. It makes most difference for

backlight and bright outdoor conditions.

Exposure Control

To achieve the required amount of exposure, the AE driver

adjusts the sensor integration time R0x9:0, R0xC:0, gains,

ADC reference, and IFP digital gains. To reject flicker,

integration time is typically adjusted in increments of

ae.R9_step. ae.R9_step specifies duration in row times

equal to one flicker period. Thus, flicker is rejected if

integration time is kept a natural factor of the flicker period.

Exposure is adjusted differently depending on

illumination situation.

•In extremely bright conditions, the exposure is set using

R0xC:0, R0x9:0, and analog gains. R0xC:0 is used to

achieve very short integration times. In this situation,

R0x9:0<ae.R9_step and flicker are not rejected.

•In bright conditions where R0x9:0> = ae., R9_step

R0x9:0 is set as a natural factor of ae.R9_step. Analog

gains are also used, but the green gain, also called

virtual gain, does not exceed 2x. ae.minVirtGain limits

minimal integration time and is expressed in flicker

periods. ae.Index indicates the current integration time

expressed in the same form.

•Under medium-intensity illumination, the integration

time can increase further. For any given exposure, the

best signal-to-noise ratio can be typically obtained by

using the longest exposure and the smallest gain setting.

However, a long exposure time can slow down the

output frame rate if the former exceeds the default

frame rate,

R0x9:0 > R0x3:0 + R0x6:0 + 1. Integration

ae.IndexTH23 specifies the breakpoint where AE

scheme, giving preference to increasing the shutter

width, is replaced with another scheme giving

preference to increase in gain. ae.maxGain23 specifies

maximum allowed gain in this situation. ae.VirtGain

indicates current green channel gain.

•In darker situations, the gain achieves ae.maxGain23

and the integration time is allowed to increase again up

to ae.maxIndex.

•In yet darker situations, once the integration time

achieves ae.maxIndex, the analog gain is allowed to

increase up to ae.maxVirtGain.

•In very dark conditions, the digital IFP gains are

allowed to increase up to ae.maxDGainAE1 and

ae.maxDGainAE2.

ADC is used as an additional gain stage by adjusting

reference levels. See ae.ADC* variables.

MT9D131

www.onsemi.com

Figure 34. Gain vs. Exposure

ae.R9_step

2 * ae.R9_step

3 * ae.R9_step

4 * ae.R9_step

ae.indexTH23

ae.maxGain23

. . .

ae.maxVirtGain

ae.maxDGainAE1 /

ae.maxDGainAE2

. . . .

(TH23 + 1) * ae.R9_step

(TH23 + 2) * ae.R9_step

(TH23 + 3) * ae.R9_step

ae.maxIndex

. . .

No Gain: Integration

Time & Shutter

Delay (up to 16 lines)

(TH23 + 4) * ae.R9_step

Normally Set To Ensure

Constant Frame Rate

Increasing Gain

Increasing Exposure Time

Lens Correction Zones

To increase the precision of the correction function, the

image plane is divided into 8 zones in each dimension. The

coordinates of zone boundaries are referenced with respect

to the lens center, C. Each boundary as well as C (Cx, Cy)

coordinate is stored as a byte, which represents the

coordinate value divided by 4. There are always three

boundaries to the left (top) of the center and three to the right

(bottom) of the center. These boundaries apply uniformly

for each color channel. However, the correction functions

are programmable independently for each color component.

Boundary and lens center positions are also valid for the

preview mode. Figure 35 illustrates the lens correction

zones.

Figure 35. Lens Correction Zones

Array

Center

MT9D131

www.onsemi.com

Lens Correction Procedure

The goal of the lens shading correction is to achieve a

constant sensitivity across the entire image area after the

correction is applied. To accomplish this, each incoming

pixel value is multiplied with a correction function F (x, y),

which is dependent on the location of the pixel.

The corrected pixel data, POUT

, can be expressed in the

followingterm:

POUT(x,y)+PIN(x,y) F(x,y)

Within each zone described above, the correction function

can be expressed with a following equation, as follows:

F(x,y)+f(x,x2))j(y,y2))k f(x,x2) j(x,x2) j(y,y2)*G

Wheref(x,x2and j(y,y2) are piecewise quadratic

polynomial functions that are independent in each x and y

dimension, and k and G are constants that can be used to

increase lens correction at the image corners (k) and to offset

the LC magnitude for all zones and colors (G).

The expressionsf(x,x2) and j(y,y2) are defined

independently for each dimension. These can be expressed

further as:f(x,x2)+aix2)bix2)ciand

j(y,y2)+diy2)eiy)fi .

To implement the function F (x, y) for each zone, the

MT9D131 provides a set of registers that allow flexible

definition of the function F (x, y). These registers contain the

following parameters:

•Operation mode R0x80:2

•Zone boundaries and center offset R0x81:2–R0x87:2

•Initial conditions of:f(x,x2) and j(y,y2) for each color

(12-bit wide) R0x88:2–R0x8D:2

•Initial conditions of the first derivative of:

f(x,x2) and j(y,y2) for each color (12-bit wide)

R0x8E:2–R0x93:2

•The second derivatives of: f(x,x2) and j(y,y2)

•The second derivatives of : for each color and each

zone (8-bit wide) R0x94:2–R0xAB:2

•Values for k(10-bit wide) and G(8-bit wide) in (2) for

all colors and zones are specified in R0xAD:2 and

R0xAE:2. Sign for k is specified in R0x80:2.

There are x2 factor that can be applied to the second

derivatives inside each zone (R0xAC:2) if correction

curvature in the particular zone is to be increased. There are

also global x2 factors for all zones in X and Y direction

located in R0x80:2. The first derivative (for both X and Y

directions) can be divided by a number (devisor) specified

in R0x80:2 before it is applied to the F function. Higher

numbers result in more precise curve (full-scale expanse).

Color Correction

Color correction in the color pipeline is achieved by:

1. Apply digital gain to raw RGB,

R0x6A:1–R0x6E:1

2. Subtract second black level D from raw RGB, see

R0x3B:1

3. Multiply result by CCM, R0x60:1–R0x66:1

4. Clip the result

C11 C12 C13

C21 C22 C23

C31 C32 C33

Rraw *GR

raw *GG

raw *GB−D

CLIP

MCU controls both CCM and D.

Decimator

To fit image size to customer needs, the image size of the

SOC can be scaled down. The decimator can reduce image

to arbitrary size using filtering. The scale-down procedure

is performed by transferring an incoming pixel from the

image space into a decimated (scaled down) space. The

procedure can be performed in both X and Y dimensions. All

the standard formats with resolution lower than 2

megapixels as well as customer-specified resolutions are

supported.

Transfer of pixel from the image into the decimated space

is done in the following way, which is the same in X and Y

directions:

Each incoming pixel is split in two parts. The first part

(P1) goes into the currently formed output-space pixel while

part two (P2) goes to the next pixel. P1 could be equal or less

than value of the incoming pixel while P2 is always less.

These two parts are obtained by multiplying the value of

incoming pixel by scaling factors f1 and f2, which sum is

always constant for the given decimation degree and

proportional to X1/X0 where X1 is size of the output image

and X0 is the size of the input image. It is denoted as

“decimation weight.”

Coefficients f1 and f2 are calculated in the

microcontroller transparently for user based on the specified

output image size and mode of SOC operation.

At large decimation degrees, several incoming pixels may

be averaged into one decimated pixel. Averaging of the

pixels during decimation provides a low pass filter, which

removes high-frequency components from the incoming

image, and thus avoids aliasing in the decimated space.

The decimator has two operational modes−normal and

high-precision. Since the intermediate result for Y

decimated pixels has to be stored in a memory buffer with

certain word width, there is a need for additional precision

at larger decimation degrees when scaling factors are small.

This is done by increasing the number of digits for each

stored value when decimation is greater than 2.

MT9D131

www.onsemi.com

SPECTRAL CHARACTERISTICS

Figure 36. Typical Spectral Characteristic

Quantum Efficiency

350 450 550 650 750 850 950 1050

Wavelength (nm)

Quantum Efficiency (%)

vs. Wavelength

Blue

Red

Green

MT9D131

www.onsemi.com

CRA vs. Image Height Plot

Image Height CRA

(%) (mm) (deg)

0 102030405060708090100

CRA (deg)

110

Image Height (%)

MT9D131 CRA Design

0 0 0

5 0.140 1.68

10 0.280 3.37

15 0.420 5.03

20 0.560 6.67

25 0.700 8.25

30 0.840 9.79

35 0.980 11.25

40 1.120 12.63

45 1.260 13.92

50 1.400 15.11

55 1.540 16.19

60 1.680 17.15

65 1.820 17.98

70 1.960 18.69

75 2.100 19.26

80 2.240 19.68

85 2.380 19.96

90 2.520 20.08

95 2.660 20.05

100 2.800 19.87

Figure 37. Chief Ray Angle (CRA) vs. Image Height

Figure 38. Optical Center Offset

Last Clear Pixel

(Col 1683, Row 1235)

First Clear Pixel

(Col 52, Row 20)

Optical Center

(167.84m, 2.06m)

Die Center

(0m, 0m)

7845.05m

(bare die)

8199.35m

(bare die)

PLL

Figure not to scale.

MT9D131

www.onsemi.com

ELECTRICAL SPECIFICATIONS

Recommended die operating temperature range is from

–20° to +55°C. The sensor image quality may degrade above

+55°C.

TABLE 41. AC ELECTRICAL CHARACTERISTICS

Parameter Symbol Conditions Min Type Max Units

Input clock frequency fEXTCLK1

PLL enabled

(MCLK max = 80 MHz)

6 10 64 MHz

Input clock period tEXTCLK1

PLL enabled

(MCLK max = 80 MHz)

15.625 100 166.7 ns

Input clock frequency fEXTCLK2 PLL disabled 6 80 MHz

Input clock period tEXTCLK2 PLL disabled 12.5 166.7 ns

Input clock rise time tR0.5 1 V/ns

Input clock fall time tF0.5 1 V/ns

Clock duty cycle 40 50 60 %

PIXCLK frequency fPIXCLK Default 6 80 MHz

PIXCLK to data valid tPD Default −3 3 ns

PIXCLK to FV HIGH tPFH Default −3 3 ns

PIXCLK to LV HIGH tPLH Default −3 3 ns

PIXCLK to FV LOW tPFL Default −3 3 ns

PIXCLK to LV LOW tPLL Default −3 3 ns

Input pin capacitance CIN 3.5 pF

Load capacitance CLOAD 15 20 pF

AC Setup Conditions

fEXTCLK1 6 64 MHz

VDD 1.7 1.8 1.95 V

VDDQ1.7 2.8 3.1 V

VAA 2.5 2.8 3.1 V

VAAPIX 2.5 2.8 3.1 V

VDDPLL 2.5 2.8 3.1 V

Output load 15 pF

TABLE 42. DC ELECTRICAL DEFINITIONS AND CHARACTERISTICS

Parameter Symbol Conditions Min Typ Max Units Note

Core digital voltage VDD 1.7 1.8 1.95 V

I/O digital voltage VDDQ1.7 2.8 3.1 V

GPI/O digital voltage VDDGPIO 1.7 2.8 3.1 V

Analog voltage VAA 2.5 2.8 3.1 V

Pixel supply voltage VAAPIX 2.5 2.8 3.1 V

PLL supply voltage VDDPLL 2.5 2.8 3.1 V

Input high voltage VIH VDDQ = 2.8 V 2.4 VDDQ+0.3 V

VDDQ = 1.8 V 1.4 VDDQ+0.3

Input low voltage VIL VDDQ = 2.8 V GND−0.3 0.8 V

VDDQ = 1.8 V GND−0.3 0.5

MT9D131

www.onsemi.com

TABLE 42. DC ELECTRICAL DEFINITIONS AND CHARACTERISTICS (continued)

Parameter NoteUnitsMaxTypMinConditionsSymbol

Input leakage current IIN No pull-up resistor; VIN = VDDQ or

DGND

–10 +/−0.5 10 μA

Output high voltage VOH At specified IOH VDDQ–0.4 V

Output low voltage VOL At specified IOL 0.4 V

Output high current IOH At specified VOH = VDDQ~400MV AT

1.7V VDDQ

–7 mA

Output low current IOL At specified VOL~400MV at 1.7V

VDDQ

7 mA

Tri-state output leakage

current IOzVIN = VDDQ or GND –10 +/−0.5 10 μA

Digital operating current IDD1Context B, 1600 x 1200, JPEG on,

MCLK = MAX, PIXCLK = MAX

92 110 mA

I/O digital operating current IDDQ1 Context B, 1600 x 1200, JPEG on,

MCLK = MAX, PIXCLK = MAX

15 mA 1

Analog operating current IAA1Context B, 1600 x 1200, JPEG on,

MCLK = MAX, PIXCLK = MAX

43 55 mA

Pixel supply current IAAPIX1 Context B, 1600 x 1200, JPEG on,

MCLK = MAX, PIXCLK = MAX

2.1 3.5 mA

PLL supply current IDDPLL1 Context B, 1600 x 1200, JPEG on,

MCLK = MAX, PIXCLK = MAX

2.3 3 mA

Digital operating current IDD2Context A, 800 x 600, No JPEG,

MCLK = MAX, PIXCLK = MAX

48 60 mA

I/O digital operating current IDDQ2 Context A, 800 x 600, No JPEG,

MCLK = MAX, PIXCLK = MAX

15 mA 1

Analog operating current IAA2 Context A, 800 x 600, No JPEG,

MCLK = MAX, PIXCLK = MAX

27 35 mA

Pixel supply current IAAPIX2 Context A, 800 x 600, No JPEG,

MCLK = MAX, PIXCLK = MAX

4 5.5 mA

PLL supply current IDDPLL2 Context A, 800 x 600, No JPEG,

MCLK = MAX, PIXCLK = MAX

2.3 3 mA

Standby current PLL enabled ISTDBY1 PLL enabled (MCLK = 0Hz, held at

either VIL or VIH)

35 100 μA

Standby current PLL

disabled ISTDBY2 PLL disabled (MCLK = 0Hz, held at

VIL or VIH)

35 100 μA

1. Due to the influence of several variables (scene illumination, output load) maximum values are not available.

TABLE 43. ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Min Max Unit

VDD Digital power –0.3 2.4 V

VDDQI/O power –0.3 4.0 V

VDDPLL PLL power –0.3 4.0 V

VAA Analog power (2.8V) –0.3 4.0 V

VAAPIX Pixel array power –0.3 4.0 V

VIN DC input voltage –0.3 VDDQ + 0.3 V

VOUT DC output voltage –0.3 VDDQ + 0.3 V

TOP Operation temperature –30 70 °C

TSTG1Storage temperature –40 85 °C

1. Stresses above those listed may cause permanent damage to the device. This is a stress rating only, and functional operation of the device

at these or any other conditions above those indicated in the product specification is not implied. Exposure to absolute maximum rating

conditions for extended periods may affect device reliability.

MT9D131

www.onsemi.com

I/O Timing

Figure 39. I/O Timing Diagram

EXTCLK

PIXCLK

tRtF

tEXTCLK

Data(7:0)

Frame Valid/

Line Valid

XXX

Note: Frame_Valid leads Line_Valid by 6 PIXCLKs.

Note: Frame_Valid trails

Line_Valid by 6 PIXCLKs.

tCP

tPFL

tPLL

tPD tPD

tPFH

tPLH

Pxl_0 Pxl_1 Pxl_2 Pxl_n

*PLL disabled for t CP

XXXXXX XXXXXX

MT9D131

www.onsemi.com

APPENDIX A: TWO-WIRE SERIAL REGISTER INTERFACE

This section describes the two-wire serial interface bus

that can be used in any functional sensor mode.

The two-wire serial interface bus enables R/W access to

control and status registers within the sensor core.

The interface protocol uses a master/slave model in which

a master controls one or more slave devices. The sensor acts

as a slave device. The master generates a clock (SCLK) that

is an input to the sensor and used to synchronize transfers.

The master is responsible for driving a valid logic level on

SCLK at all times. Data is transferred between the master and

the slave on a bidirectional signal (SDATA). Both the SDATA

AND SCLK signal are pulled up to VDD off-chip by a 1.5KΩ

resistor. Either the slave or master device can drive the

SDATA line low−the interface protocol determines which

device is allowed to drive the SDATA line at any given time.

Protocol

The two-wire serial interface bus defines the transmission

codes as follows:

•a start bit

•the slave device 8-bit address

•a(an) (no) acknowledge bit

•an 8-bit message

•a stop bit

Sequence

A typical read or write sequence is executed as follows:

1. The master sends a start bit.

2. The master sends the 8-bit slave device address.

The last bit of the address determines if the request

is a read or a write, where a “0” indicates a write

and a “1” indicates a read.

3. The slave device acknowledges receipt of the

address by sending an acknowledge bit to the

master.

4. If the request is a write, the master then transfers

the 8-bit register address, indicating where the

write takes place.

5. The slave sends an acknowledge bit, indicating

that the register address has been received.

6. The master then transfers the data, 8 bits at a time,

with the slave sending an acknowledge bit after

each 8 bits.

The sensor core uses 16-bit data for its internal registers,

thus requiring two 8-bit transfers to write to one register.

After 16 bits are transferred, the register address is

automatically incremented so that the next 16 bits are

written to the next register address. The master stops writing

by sending a start or stop bit.

A typical read sequence is executed as follows.

1. The master sends the write-mode slave address

and 8-bit register address, just as in the write

request.

2. The master then sends a start bit and the

read-mode slave address, and clocks out the

3. The master sends an acknowledge bit after each

8-bit transfer. The register address is

auto-incremented after every 16 bits is transferred.

4. The data transfer is stopped when the master sends

a no-acknowledge bit.

Bus Idle State

The bus is idle when both the data and clock lines are high.

Control of the bus is initiated with a start bit, and the bus is

released with a stop bit. Only the master can generate start

and stop bits.

Start Bit

The start bit is defined as a HIGH-to-LOW data line

transition while the clock line is HIGH.

Stop Bit

The stop bit is defined as a LOW-to-HIGH data line

transition while the clock line is HIGH.

Slave Address

The 8-bit address of a two-wire serial interface device

consists of 7 bits of address and 1 bit of direction. A “0” in

the LSB (least significant bit) of the address indicates write

mode, and a “1” indicates read mode. The default slave

addresses used by the sensor core are 0xBA (write address)

and 0xBB (read address). R0x0D:0[10] or the SADDR pin can

be used to select the alternate slave addresses 0x90 (write

address) and 0x91 (read address).

Writes to R0x0D:0[10] are inhibited when the STANDBY

signal is asserted (all other writes proceed normally). This

allows two sensors to co-exist as slaves on this interface, but

they must be addressed independently. Enable this

capability as follows:

After RESET, both sensors use the default slave address.

READS or WRITES on the serial register interface to the

default slave address are decoded by both sensors

simultaneously.

1. After RESET, assert the STANDBY signal to one

sensor and negate the STANDBY signal to the

other sensor.

2. Perform a write to R0x0D:0 with bit 10 set. The

sensor with STANDBY asserted ignores the write

to bit 10 and continues to decode at the default

slave address.

The sensor with STANDBY negated has its R0x0D:0[10]

set and responds to the alternate slave address for all

subsequent READ and WRITE operations, as shown in

Table 43.

MT9D131

www.onsemi.com

TABLE 44. SLAVE ADDRESS OPTIONS

SADDR R0xD:0[10]

Slave Address

WRITE READ

0 0 0x090 0x091

0 1 0x0BA 0x0BB

1 0 0x0BA 0x0BB

1 1 0x090 0x091

Data Bit Transfer

One data bit is transferred during each clock pulse. The

serial interface clock pulse is provided by the master. The

data must be stable during the high period of the two-wire

serial interface clock−it can only change when the serial

clock is LOW. Data is transferred 8 bits at a time, followed

by an acknowledge bit.

Acknowledge Bit

The master generates the acknowledge clock pulse. The

transmitter (which is the master when writing, or the slave

when reading) releases the data line, and the receiver

indicates an acknowledge bit by pulling the data line LOW

during the acknowledge clock pulse.

No-Acknowledge Bit

The no-acknowledge bit is generated when the data line is

not pulled down by the receiver during the acknowledge

clock pulse. A no-acknowledge bit is used to terminate a

read sequence.

Page Register

The MT9D131 two-wire serial interface and its associated

protocols support an address space of 256 16-bit locations.

This address space is extended by a 3-bit page prefix, and

controlled through accesses to R0xF0:0.

The paging mechanism is intended to allow access to

other sets of registers when the sensor is embedded as part

of a more complex integrated subsystem, for example, in an

SOC. All registers within the sensor core are accessible on

page 0 (the default page).

Sample Write and Read Sequences

16-Bit Write Sequence

A typical write sequence for writing 16 bits to a register

is shown in Figure 40. A start bit given by the master starts

the sequence, followed by the write address. The image

sensor then sends an acknowledge bit and expects the

After each 8-bit transfer, the image sensor sends an

acknowledge bit. All 16 bits must be written before the

address is automatically incremented so that the next 16 bits

are written to the next register. The master stops writing by

sending a start or stop bit.

Figure 40. WRITE Timing to R0x09:0−Value 0x0284

SCLK

SDATA

Sto

ACK ACK ACK ACK

R0x09 0000 0010 1000 0100

0XBA Address

Start

16-Bit Read Sequence

A typical read sequence is shown in Figure 41. First the

master writes the register address, as in a write sequence.

Then a start bit and the read address specify that a read is

about to happen from the register. The master clocks out the

acknowledge bit after each 8-bit transfer. The register

address should be incremented after every 16 bits is

transferred. The data transfer is stopped when the master

sends a no-acknowledge bit.

MT9D131

www.onsemi.com

100

Figure 41. READ Timing to R0X09:0, Returned Value 0x0284

SCLK

DATA

0xBA Address 0xBA Address R0xF1 1000 0100

Start Start Stop

ACK ACK ACK ACK ACK ACK

R0x09 0000 0010

8-Bit Write Sequence

To be able to write 1 byte at a time to the register, a special

the upper 8 bits to the desired register, then writing the lower

8 bits to the special register address (R0xF1:0). The register

is not updated until all 16 bits have been written. It is not

possible to update just half of a register. In Figure 42, a

typical sequence for 8-bit writes is shown. The second byte

is written to the special register (R0xF1:0).

Figure 42. WRITE Timing to R0x09:0−Value 0x0284

SCLK

DATA

0xBA Address 0xBA Address R0xF1 1000 0100

Start Start Stop

ACK ACK ACK ACK ACK ACK

R0x09 0000 0010

8-Bit Read Sequence

To read one byte at a time, the same special register

address is used for the lower byte. The upper 8 bits are read

from the desired register. By following this with a read from

the special register (R0xF1:0), the lower 8 bits are accessed

(Figure 43). The master sets the no-acknowledge bits.

Figure 43. READ Timing from R0x09:0; Returned Value 0x0284

SCLK

SDATA

ACK ACK ACK NACK

R0x09 0xBB Address 0000 0010

SCLK

SDATA

ACK ACK ACK NACK

R0xF1 0xBB Address 1000 0100

S S

MT9D131

www.onsemi.com

101

Figure 44. Two-Wire Serial Bus Timing Parameters

tSRTH tSCLK

Write Start

Write Address

Bit 7

ACK

Bit 0

Stop

Read Start ACK

Write Address

Bit 0

Read Address

Bit 7

Read Address

Bit 0

Bit 7

Bit 0

tSDS

tSDH tSHAW tAHSW

tSTPS tSTPH

tSHAR tAHSR tSDHR tSDSR

SCLK

SDATA

SCLK

SDATA

READ SEQUENCE

WRITE SEQUENCE

Bit

NOTE: Read waveforms start after a write command and register address are issued. They are for an 8-bit read.

TABLE 45. TWO-WIRE SERIAL BUS CHARACTERISTICS

Parameter Symbol Conditions Min Typ Max Units

Serial interface input clock frequency fSCLK fEXTCLK/16 kHz

Serial interface input clock period tSCLK 1/fSCLK ns

SCLK duty cycle 40 50 60 %

Start hold time tSRTH WRITE/READ 4*tEXTCLK ns

SDATA hold tSDH WRITE 4*tEXTCLK ns

SDATA setup tSDS WRITE 4*tEXTCLK ns

SDATA hold to ACK tSHAW WRITE 4*tEXTCLK ns

ACK hold to SDATA tAHSW WRITE 4*tEXTCLK ns

Stop setup time tSTPS WRITE/READ 4*tEXTCLK ns

Stop hold time tSTPH WRITE/READ 4*tEXTCLK ns

SDATA hold to ACK tSHAR READ 4*tEXTCLK ns

ACK hold to Sdata tAHSR READ 4*tEXTCLK ns

SDATA hold tSDHR READ 4*tEXTCLK ns

SDATA setup tSDSR READ 4*tEXTCLK ns

Serial interface input pin capacitance CIN_SI 3.5 pF

SDATA max load capacitance CLOAD_SD 15 pF

SDATA pull-up resistor RSD 1.5 KΩ

1. Either the slave or master device can drive the SCLK line LOW−the interface protocol determines which device is allowed to drive the SCLK

line at any given time.

MT9D131

www.onsemi.com

102

ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.

ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent

coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. ON Semiconductor reserves the right to make changes without further notice to any products herein.

ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability

arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.

Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards,

regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor data sheets and/or

specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer

application by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not

designed, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification

in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized

application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and

expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such

claim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. This

literature is subject to all applicable copyright laws and is not for resale in any manner.

PUBLICATION ORDERING INFORMATION

N. American Technical Support: 800−282−9855 Toll Free

USA/Canada

Europe, Middle East and Africa Technical Support:

Phone: 421 33 790 2910

Japan Customer Focus Center

Phone: 81−3−5817−1050

MT9D131/D

LITERATURE FULFILLMENT:

Literature Distribution Center for ON Semiconductor

19521 E. 32nd Pkwy, Aurora, Colorado 80011 USA

Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada

Fax: 303−675−2176 or 800−344−3867 Toll Free USA/Canada

Email: orderlit@onsemi.com

ON Semiconductor Website: www.onsemi.com

Order Literature: http://www.onsemi.com/orderlit

For additional information, please contact your local

Sales Representative

◊

Mouser Electronics

Authorized Distributor

Click to View Pricing, Inventory, Delivery & Lifecycle Information:

ON Semiconductor:

MT9D131C12STCD3-GEVK MT9D131C12STCH-GEVB