AK8811_12 Datasheet, PDF (22/36 Pages) Asahi Kasei Microsystems – NTSC/PAL Digital Video Encoder

ASAHI KASEI
[AK8811/12]
♦ AK8811/12 Interface Timing (Part 2) Slave mode
On slave mode operation, HSYNC and FID or VSYNC (Selected by register) are input to
AK8811/12.
AK8811/12 monitors the transition of HSYNC at the timing of the rising edge of SYSCLK.
(Refer to AC Characteristic 2-1. [Input Synchronizing Signal]) After AK8811/12 recognizes
HSYNC is Low-logic, AK8811/12 sets the slot number to the 32nd/24th(NTSC/PAL),
internally, then AK8811/12 starts to sample the data as Cb on 276th/288th(NTSC/PAL) slot.
Video field is recognized the transition timing between FID/VSYNC and HSYNC. (Fig.10.
Video Field) As in the figure, there is a toreralnce of ±1/4H.
244T
(264T)
Cb Y Cr Y
ITU-R. BT601(656)
HSYNC
32
276
(24)
(288)
Fig. 9. Interfacing timing (Slave mode)
27MHz SYSCLK
NTSC(PAL)
T=1/27MHz
* Uncertainty of 1T occurs
according to the Reset
timing.
ODD Field
Start
EVEN Field
Start
Rev.1.1
1H
1/2 H
1/2 H
1/2 H
1/2 H
Fig. 10. Video Field
22
HSYNC
FID/VSYNC
FID/VSYNC
2000/01