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WM8146

WOLFSON MICROELECTRONICS LTD

PP Rev 1.1 January 2000

11

internal signals to control the sampling of the video signal. MCLK to VSMP ratios and maximum

sample rates for the various modes are shown in Table 1.

POWER SUPPLY

The WM8146 can run from a 5V single supply or from split 5V (core) and 3.3V (digital interface)

supplies.

OPERATING MODES

Table 1 summarises the most commonly used modes, the clock waveforms required and the register

contents required for CDS and non-CDS operation.

MODE

DESCRIPTION

CDS

AVAILABLE

MAX

SAMPLE

RATE

SENSOR

INTERFACE

DESCRIPTION

TIMING

REQUIRE-

MENTS

REGISTER

CONTENTS

WITH

CONTROL

BIT CDS=1

REGISTER

CONTENTS

WITH

CONTROL

BIT CDS=0

1

Colour

Pixel-by-Pixel

Yes

2MSPS

The 3 input channels

are sampled in

parallel. The signal is

then gain and offset

adjusted before being

multiplexed into a

single data stream and

converted by the ADC,

giving an output data

rate of 6MSPS max.

MCLK max =

12MHz

MCLK:VSMP

ratio is 6:1

SetReg1:

03(hex)

SetReg1:

01(hex)

2

Monochrome/

Colour

Line-by-Line

Yes

2MSPS

As mode 1 except:

Only one input

channel at a time

is continuously

sampled.

MCLK max =

12MHz

MCLK:VSMP

ratio is 6:1

SetReg1:

07(hex)

SetReg3 bits

7:6

determine

which input is

to be

sampled

SetReg1:

05(hex)

SetReg3

bits 7:6

determine

which input

is to be

sampled

3Fast

Monochrome/

Colour

Line-by-Line

Yes

4MSPS

Identical to mode 2

MCLK max =

12MHz

MCLK:VSMP

ratio is 3:1

Identical to

mode 2 plus

SetReg3: bits

5:4 must be

set to 0(hex)

Identical to

mode 2

4

Maximum

speed

Monochrome/

Colour

Line-by-Line

No

6MSPS

Identical to mode 2

MCLK max =

12MHz

MCLK:VSMP

ratio is 2:1

CDS not

possible

SetReg1:

45(hex)

SetReg3

bits 7:6

determine

which input

is to be

sampled

5

Slow Colour

Pixel-by-Pixel

Yes

1.5MSPS

Identical to mode 1

MCLK max =

12MHz

MCLK:VSMP

ratio is

2n:1, n

≥ 4

Identical to

mode 1

Identical to

mode 1

6Slow

Monochrome/

Colour

Line-by-Line

Yes

1.5MSPS

Identical to mode 2

MCLK max =

12MHz

MCLK:VSMP

ratio is

2n:1, n

≥ 4

Identical to

mode 2

Identical to

mode 2

Table 1 WM8146 Operating Modes