2 POWER SUPPLY, RESET, AND CLOCKS
S1C17M12/M13 TECHNICAL MANUAL
Seiko Epson Corporation
2-5
(Rev. 1.2)
OSC3
OSC4
X’tal3/Ceramic3
CLG
IOSCCLK
SYSCLK
SLEEP, WAKE-UP
EXOSC
FOUT
IOSCEN
CLKSRC[1:0]
CLKDIV[1:0]
WUPMD
CLKSRC[x:0]
CLKDIV[x:0]
WUPSRC[1:0]
WUPDIV[1:0]
FOUTDIV[2:0]
IOSC
oscillator
circuit
Divider
Clock
selector
System
clock
controller
OSC3CLK
OSC3EN
OSC3
oscillator
circuit
Divider
EXOSCCLK
EXOSCEN
EXOSC
clock input
circuit
FOUTEN
FOUT
output
circuit
Peripheral circuit 1
CLKSRC[x:0]
CLKDIV[x:0]
Peripheral circuit n
To CPU and bus
Inter
nal data
bu
s
Clock
selector
Clock
selector
Figure 2.3.1.1 CLG Configuration
2.3.2 Input/Output Pins
Table 2.3.2.1 lists the CLG pins.
Table 2.3.2.1 List of CLG Pins
Pin name
I/O
*
Initial status
*
Function
OSC3
A
–
OSC3 oscillator circuit input
OSC4
A
–
OSC3 oscillator circuit output
EXOSC
I
I
EXOSC clock input
FOUT
O
O (L)
FOUT clock output
*
Indicates the status when the pin is configured for CLG.
If the port is shared with the CLG input/output function and other functions, the CLG function must be assigned to
the port. For more information, refer to the “I/O Ports” chapter.
2.3.3 Clock Sources
IOSC oscillator circuit
The IOSC oscillator circuit features a fast startup and no external parts are required for oscillating. Figure 2.3.3.1
shows the configuration of the IOSC oscillator circuit.
IOSC oscillator circuit
Inter
nal data
bu
s
IOSCEN
Clock
oscillator
Oscillation
stabilization
waiting circuit
Interrupt
control circuit
Interrupt
controller
IOSCCLK
IOSCSTAIE
IOSCSTAIF
Figure 2.3.3.1 IOSC Oscillator Circuit Configuration
The IOSC oscillator circuit output clock IOSCCLK is used as SYSCLK at booting. For the oscillation charac-
teristics, refer to “IOSC oscillator circuit characteristics” in the “Electrical Characteristics” chapter.