AK8825 Datasheet, PDF (114/162 Pages) Asahi Kasei Microsystems – HD/SD Multi Format Video Encoder with 3ch DAC

(2) Slave mode
On slave mode operation, HSYNC and VSYNC are input to AK8825.
[AK8825]
AK8825 monitors the transition of HSYNC at the timing of the rising edge of SYSCLK. After AK8825 recognizes HSYNC is
Low-logic, AK8825 sets the slot number to the 32nd/24th (NTSC/PAL), internally, then AK8825 starts to sample the data as Cb
on 276th/288th (NTSC/PAL) slot.
Video field is recognized the transition timing between VSYNC and HSYNC. As in the figure, there is a tolerance of ±1/4H.
This interface mode is set by REC656-bit =0 of SD Blanking Set Register (R/W) [Sub Address 0x10].
244T / 264T (525/625)
27MHz
Data
HDI
Cb₀
Y₀
Cr₀
Y₁
Cb₁
Y₂
Cr₁
Fig. 156 Relation between HSYNC and Data
Field Detection with HSYNC and VSYNC
1/2 H 1/2 H
HDI
1st Field
VDI
2nd Field
VDI
1/4 H 1/4 H
1/4 H 1/4 H
Fig. 157 HD/VD timing
Rev-E-00
114
2008/03