[AK4706]
■ System Reset and Full Power-down Mode
The AK4706 should be reset once by bringing PDN pin = “L” upon power-up.
PDN pin: Power down pin
“H”: Normal operation
“L”: Device power down.
■ Auto Startup Mode
When the PDN pin is set to “H”, the AK4706 is in the auto startup mode. In this mode, all blocks except for the video
detection circuit are powered down. Once the video detection circuit detects video signal from TVVIN pin or VCRVIN
pin, the AK4706 goes to the stand-by mode (Both Fast Blanking and Slow Blanking are also fixed to VCR-TV
Loop-through) automatically and sends “H” pulse via INT pin. To exit the auto startup mode, set the AUTO bit to “0”.
The HD video outputs in the auto startup mode are disable at power-up. In this mode, HD video outputs are controlled as
shown in Table 3.
AUTO bit (00H D3): Auto startup bit (SD Video output)
“1”: Auto startup enable (default).
“0”: Auto startup disable (Manual startup).
HDAPW bit (0AH D5): Auto startup bit (HD Video output)
“1”: Auto startup enable.
“0”: Auto startup disable (Manual startup: default).
AUTO bit
HDAPW bit
HD Video output
0
0
1
1
0
1
0
1
Set by HDSW1/0, HDCP1/0 bit
Hi-Z
Hi-Z
Set by HDSW1/0, HDCP1/0 bit
after a video signal is detected.
Table 3. HD Video output status
The Figure 2 shows an example of the system timing at auto startup mode.
Auto startup enable
PDN pin
Low Power Mode
Low Power Mode
Low Power Mode
AUTO bit
“1”(defaoult)
HDAPW bit
“0” (default)
“1”
Clock, Data in
don’t care
TVVIN
don’t care
don’t care
No Signal
Signal in
No Signal
No Signal
Signal in
No Signal
No Signal
Hi-Z
don’t care
don’t care
VCRVIN
Signal in
TVVOUT,
Hi-Z
Active (loop-through)
Hi-Z
Active (loop-through)
VCRVOUT
HD Video
OUTPUT
Hi-Z
Active
Hi-Z
Active
Hi-Z
Active (loop-through)
Active (loop-through)
Audio out (DC)
(GND)
Figure 2.Auto startup mode sequence
MS0507-E-01
2010/09
- 21 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
