Sony SS-HQ1 Application Notes page 211

ECK-28MHz INT / ECK-27MHz LL Switching System (manual setting)
This system switches between LL and INT depending on whether the DIP switch is set to "High" or "Low".
INT mode operates with 28MHz ECK input. LL mode uses 27MHz ECK input.
After the DIP switch position is changed, the RESET operation must be performed, both when changing from
INT to LL, and when changing from LL to INT.
Therefore, when switching between INT and LL, first turn off the power, then change the DIP switch position,
and then turn the power back on.
A block diagram of the system is shown in Fig 12.2-14.
SYSSELFLG is assigned to a port in advance. See Table 12.2-16, Table 12.2-17, Table 12.2-18, and Table
12.2-19 for information on SYSSELFLG and the parameter settings that are switched according to the
SYSSELFLG value.
When switching from INT to LL (when the DIP switch is set to the "High" position), the following operations are
performed.
• SYSSELFLG, which is assigned to a specified port, is set to 1[h] to switch MODESEL/SGMODE to the LL setting.
• The MCK switching circuit is switched to the VCO position (MCK clock supply).
• The ECK switching circuit is switched to the 27MHz position (ECK 27MHz clock supply).
When switching from LL to INT (when the DIP switch is set to the "Low" position), the following operations are
performed.
• SYSSELFLG, which is assigned to a specified port, is set to 0[h] to switch MODESEL/SGMODE to the INT setting.
• The MCK switching circuit is switched to the GND position (MCK clock supply stopped).
• The ECK switching circuit is switched to the 28MHz position (ECK 28MHz clock supply).
LL mode
"H"
27MHz
(X'tal)
28MHz "L"
(X'tal)
INT mode
Fig 12.2-14 ECK-28MHz INT/ECK-27MHz LL Switching System Block Diagram
* Do not assign SGMODE to a port.
ESCI
86
ESCO
87
88
ECK
CXD3172AR
LPF
PCOMP
42
(V-PLL)
VCO
(LC)
LL mode
"H"
"L"
INT mode
INT/LL Change signal
EXVIDEO
58
EXVIDEOY 57
S1
46
S0
44
XRST
11
43
DIPSW
205
- SS-HQ1 Application Notes -
Ver.1.0.0 January 7, 2005
3.3V
EXT-VD
Reset
Circuit
3.3V
INT : L
LL : H