ASAHI KASEI
(1) Reset
[AK8817/18]
Video Encoder Functional Outline
(1-1) Reset of Serial Interface part ( asynchronous reset )
Reset is made by setting RSTN pin to low.
(1-2) Reset of other than Serial Interface blocks
Reset is made by keeping RSTN pin low for a longer than 100 clock time, in normal operation.
(1-3) at Power-On-Reset ( including power-down release case )
Follow the power-on-reset sequence.
At the completion of each initialization, all internal registers are set to default values ( refer to Register Map ). Right after
the reset, Video output of the AK8817/18 is put into Hi-Z condition.
(2) Power-Down
It is possible to put the device into power-down mode by setting the AK8817/18 power-down pin to GND.
Transition to power-down mode should be followed by the power-down sequence. As for the recover from the
power-down mode, it should be followed by the power-down release sequence.
(3) Master Clock
A following clock should be input as a Master clock.
In Encoder Mode operation ( a synchronized clock with input data is required )
When ITU-R BT.601 data is input
When Square Pixel data is input
( PIXRT-bit = 1 )
24.5454MHz
( PIXRT-bit = 0 )
NTSC Encoder
PAL Encoder
27MHz
27MHz
29.50MHz
(4) Video Signal Interface
Video input signal ( data ) should be synchronized in either of the following methods :
* Slave mode operation where synchronization is made with HSYNC ( HDI ) / VSYNC ( VDI ).
* ITU-R BT. 656 I / F ( EAV decode ) (only 27MHz operation)
(5) Pixel Data
Input data to the AK8817/18 is YCbCr ( 4:2:2 ).
Data with
Y : 16 ~ 235 and CbCr : 16 ~ 240 should be input.
(6) Video Signal Conversion
Video Re-Composition module converts the multiplexed data ( ITU-R BT.601 Level Y, Cb, Cr ) into interlaced
NTSC-M and PAL-B, D, G, H, I data. Video encoding setting is done by “Control 1 Register “.
Rev.001E
19
2009 / 12
AKM [ ASAHI KASEI MICROSYSTEMS ]
