PixArt Imaging Inc.
PAS005B
CMOS Image Sensor IC
EXAMPLE_3: QVGA Exposure time setting
when system clock 48M hz
pxclk
12M hz
2/120 sec
exposure time
Please keep L_P_F = 241
and Calculate Ny = ? and Ne = ? ,
Application
System_clk
48
Np
4
Pixel_clk
12
Power frequency EX_time (x/120)
60HZ
2
C_nov
6
L_P_F
frame_rate<60
59.9760096
241
Register setting
CM
1
row_average
CDSx2
single_path
1
1
1
Wcw
1287
Wrd
967
cf
2
rf
2
Key in Register
L_P_F
Ny
0
Ne
31
t_line
820
241
1.ExposureTim ={[(LPF+1+2)-Ny]*t_line- Ne}/Pxclk
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
1
5. Frame rate =
= 1/(241+3)* 820 = 60
(LPF +1+ 2)⋅t _ line
All rights strictly reserved any portion in this paper shall not be reproduced, copied or transformed to any other forms without permission.
PixArt Imaging Inc.
E-mail: fae_service@pixart.com.tw
PIXART [ PIXART IMAGING INC. ]
