AK8855 Datasheet, PDF (17/81 Pages) Asahi Kasei Microsystems – NTSC/PAL Digital Video Decoder

[ASAHI KASEI]
AK8855
Input Signal
Decodable Video signals by the AK8855 are,
- NTSC
- PAL-B, -D, -G, -H, -I.
Those input signal types are set by Input Video Standard Register ( R/W ) [ Sub Address 0x00].
Input signal is converted into digital code as follows.
Clamp Block ---- Anti-aliasing Filter ---- PGA Block ---- ADC Block
Then the digitized signal is signal-processed in digital block.
Setting of Input Video Standard Register ( R/W ) [ Sub Address 0x00 ] is described here.
This register is the setting register to set input signal attribute. Bit allocation of the register is as follows.
Sub Address 0x00
bit 7
bit 6
Reserved Reserved
bit 5
Reserved
0
0
0
bit 4
bit 3
AINSEL
VLF
Default Value
0
0
bit 2
VCEN
0
Default Value : 0x00
bit 1
bit 0
VSCF1
VSCF0
0
0
[ VSCF1 : VSCF0 ]-bit
setting of input signal sub-carrier is made by [ VSCF1 : VSCF0 ]-bit.
Sub-carrier
[VSCF1:VSCF0]-bit
frequency
Conditions
[MHz]
[00]
3.57954545
NTSC
[01]
3.57561188
[10]
3.582054
[11]
4.43361875
PAL-B,D,G,H,I
[ VCEN ]-bit
setting of input signal Color Encoding system is set by [ VCEN]-bit.
[VCEN]-bit
Color Encoding system
Conditions
0
NTSC
1
PAL
[ VLF]-bit
setting of number of lines per each Frame of input signal is made by [ VLF]-bit.
[VLF]-bit
Number of lines
Conditions
0
525 lines
1
625 lines
[ AINSEL ]-bit
selection of input signal is made.
[AINSEL]-bit
Input signal
0
AIN1 input is selected
1
AIN2 input is selected
Conditions
MS0319-E-03
17
2004 / 11