- SS-HQ1 Application Notes -
Ver.1.0.0 January 7, 2005
207
• VD Detection Circuit
There is no particular external VD detection circuit which is recommended by Sony.
Build a detection circuit based on the system switching timings shown below.
Fig 12.2-16 VD Detection Circuit Block Diagram
1. Timing for switch from INT to LL when external VD input is detected (INTSW input =High)
For a fixed period of time (1VD period or longer), Ext-VD presence/absence detection is performed. If Ext-VD
presence is detected, “RESET output” is switched from High to Low and the CXD3172AR is reset. In addition,
for the period where “RESET output”=Low, “INT/LL Change signal output” is switched from Low to High. (The
“INTSW input” at this time is always High.)
Fig 12.2-17 Timing for switch from INT to LL based on external VD input (INTSW input =High)
EXT-VD
input
INT/LL Change signal
output
XRST
VD Detection Circuit
Reset Circuit
LL : H
INT : L
3.3V
INTSW
input
RESET
input
RESET
output
CXD3172AR
Pn *1
SYSSELFLG
11
DIPSW
INTSW
input
EXT-VD
input
RESET
output
INT/LL
Change signal
output
Don't Care
500ns Over
Don't Care
LL
INT
Don't Care
No pulse
Detect point
pulse
High