AK8815 Datasheet, PDF (20/37 Pages) Asahi Kasei Microsystems – NTSC/PAL Digital Video Encoder

ASAHI KASEI
( 2 ) PAL ( Frame ) 625 Line 576 active lines
The First Field ( ODD )
625
1
2
3
4
5
HSYNC
[AK8815/16]
313 lines
22
23
288 lines
24
310
311
312
313
314
VSYNC
* ) VSYNC negative-going occurs during HSYNC = L at Line 1.
VSYNC positive-going can occur at arbitrary location, but as a rough idea, keep VSYNC low for 2.5, or 2 or 3 line duration time.
The Second Field ( EVEN )
313
314
315
316
317
318
HSYNC
313 lines
335
336
288 lines
337
623
624
625
1
2
VSYNC
High
* ) VSYNC negative-going is not required for the Second Field. It is required for the First Field only.
When VSYNC is input in the specified timing (described below) at the Second Field, the line and the field are set once as the Second Field.
But since the Burst cycle etc. is referenced to the First Field, VSYNC synchronization cannot be made at the Second Field only.
System synchronization must be made to reference the VSYNC synchronization at the First Field.
When to input VSYNC at the Second Field, it should be done after the first 1/2 H of the 313^th Line and before the falling edge of the 314^th HSYNC ( if HSYNC falling
edge timing of the 313^th line is counted as the 0^th clock, VSYNC should be fallen after the 944^th clock and before the 1887^th clock ).
MS0331-E-00
20
2004 / 08