AK8855 Datasheet, PDF (60/81 Pages) Asahi Kasei Microsystems – NTSC/PAL Digital Video Decoder

[ASAHI KASEI]
AK8855
Variable Frame Rate Function
The AK8855 can vary output Frame rate.
Frame rate can be selected by [ FRMRT 1 : FRMRT 0 ]-bits of Control Register ( R/W ) [ Sub Address 0x04 ]
as follows.
NTSC : 30 / 15 / 7.5 [ fps ]
PAL : 25 / 12.5 / 6.25 [ fps ]
Output Timing is shown as follows. indicates “ active “.
QVGA, CIF, QCIF, Rotated QVGA, Rotated CIF
Field
DVALID(ODEV 0,30fps)
DVALID(ODEV 1,30fps)
DVALID(ODEV 0,15fps)
DVALID(ODEV 1,15fps)
DVALID(ODEV 0,7.5fps)
DVALID(ODEV 1,7.5fps)
VGA,601
Field
DVALID(30fps)
DVALID(15fps)
DVALID(7.5fps
Note 1 : Above diagrams are common for each of OFORM and OIF modes.
Note 2 : when OIF[ 1:0 ] = 2’b 10 is set, VD / VAF are not output but it is output even during such Field ( Frame )
where HD / HV, DVALID are not output.
Note 3 : in VGA, 601 mode, ODEV setting does not affect output.
Note 4 : when Vertical Sync is disturbed during switching signals etc., above timing may not temporarily be
satisfied.
Digital Pixel Interpolator
This function is equipped to align pixel position in vertical direction.
MS0319-E-03
60
2004 / 11