3. Detailed Description of Functions
S1V30333/300/120 Evaluation Board
EPSON 7
User Guide (Rev. 1.03)
3. Detailed Description of Functions
3.1 Power
Supply
The evaluation board generates 3.3 V and 1.8 V power supplies via a regulator from the single 5 V
DC power supply received from the J5 PC USB interface connector. Space is also provided for an
optional AC adapter (CENTER -, minimum rated output 1 A, DC jack external diameter 5.5 mm,
internal diameter 2.1 mm). When using both the USB and AC adapter power supplies, select one of
the two using the SW3 power supply selector switch designed to prevent shorting between the two
power supply inputs. See Table 3-1.
LED4 indicates whether the power supply is on or off, illuminating when the power supply is on and
going out when the power supply is off. See Table 3-2.
Table 3-1 Power supply selection
SW3 setting
Power supply
Remarks
BUS
USB power supply
Default
SELF
AC adapter power supply
Component: CLIFF
FC68148 or equivalent
Table 3-2 LED4 power supply switching
Power supply
on/off
LED4 state
Remarks
ON Illuminated
OFF Off
3.2 Clocks
Table 3-3 lists the different IC clocks used on the evaluation board.
Table 3-3 Clocks
Frequency Use
12.288MHz S1V30333
clock
32.768kHz S1V30300
clock
S1V30120
clock
S1C33E07 RTC clock
14.7456MHz
S1C33E07 system clock
