PixArt Imaging Inc.

PAS005B

CMOS Image Sensor IC

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PixArt Imaging Inc.

EXAMPLE_2: VGA Exposure time setting

when

system clock 48M hz

pxclk

16M hz

exposure time

4/120 sec

Please keep L_P_F = 483

and Calculate Ny = ? and Ne = ? ,

Application

System_clk

Np

Pixel_clk

48

3

16

Power frequency EX_time (x/120)

60HZ

4

L_P_F

C_nov

frame_rate<30

483

0

28.98046717

Register setting

3

CM

row_average

CDSx2

single_path

1

1

1

1

Wcw

Wrd

Cf

rf

1287

967

1

1

Key in Register

L_P_F

Ny

Ne

t_line

483

16

332

1136

2. t_line = (active_line_pixel + t_nov + 12) = 644 + 480 + 12 = 1136 Pxclk

t_nov = 480 + Cov Pxclk

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

16 = INT [(483+3 ) - (( 4 /120

* 16 M ) / 1136 )]

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

332 = Res[( 483 + 3 ) - (( 4/120

* 16 M

) / 1136 )]

* 644

line

t

LPF

_

)

2

1

(

1

⋅

+

+

= 1/(483+3)* 1136 = 29

5. Frame rate =