PAS5101CS Specification

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PixArt Imaging Inc.

v1.0 2005/4/27

3.7. Sub-Sampling

PAS5101CS can be programmed to output image in VGA、 QVGA and QQVGA size. In the VGA sub-

sampling mode, both vertical and horizontal pixels are sub-sampling at 1/2; In QVGA sub-sampling mode,

both vertical and horizontal pixels are sub-sampling at 1/4; While in QQVGA sub-sampling mode, sub-

sampling at 1/8. By programming Skip_Analog and Skip_Digital, The maximum sub-sampling rate is

1/32 ( Skip_Analog + Skip_Digital ).

3.7.1. Skip_Analog

Sub-sampling ( Skip_Analog ) to VGA ( 640x480 ) pixels readout ( With 4 dark lines ):

H_Start[9:0] = 0,

V_Start[8:0] = 0,

H_Size[9:0] = 1287,

V_Size[8:0]= 1035,

LPF[7:0] = 519,

Nov_Size_By4[7:0] = 63, Skip_Analog = 1 ( sub-sampling 1/2 )

Figure 3.6

Valid pixel = ( H_Size + 1 ) / Skip_Analog = 1288 / 2 = 644

Valid line = (((( V_Siez + 1 ) – 4 ) / Skip_Analog ) + 4) = (((( 1035 + 1 ) – 4 ) / 2 ) + 4 ) = 520

Figure 3.7 Inter-line timing of W.O.I