PixArt Imaging Inc.

PAS005B

CMOS Image Sensor IC

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PixArt Imaging Inc.

EXAMPLE_3: QVGA Exposure time setting

when

system clock 48M hz

pxclk

12M hz

exposure time

2/120 sec

Please keep L_P_F = 241

and Calculate Ny = ? and Ne = ? ,

Application

System_clk

Np

Pixel_clk

48

4

12

Power frequency

EX_time (x/120)

60HZ

2

L_P_F

C_nov

frame_rate<60

241

6

59.9760096

Register setting

CM

row_average

CDSx2

single_path

1

1

1

1

Wcw

Wrd

cf

rf

1287

967

2

2

Key in Register

L_P_F

Ny

Ne

t_line

241

0

31

820

2. t_line = (active_line_pixel + t_nov + 12) = 322 + 486 + 12 = 820 Pxclk

t_nov = 480 +Cov Pxclk = 486 Pxclk

3. Ny = INT[(L_P_F+3) - (( EX_Time * Pxclk ) / t_line)]

0 = INT [(241 + 3 ) - (( 2/120

* 12 M ) / 820 )]

4.Ne = Res[(L_P_F + 3) - (( EX_Time * Pixel_clk ) / t_line)] * active_line_pixel

31 = Res[(241

+3) - (( 2/120

*12 M

) / 820 )]

* 322

line

t

LPF

_

)

2

1

(

1

⋅

+

+

= 1/(241+3)* 820 = 60

5. Frame rate =