2 POWER SUPPLY, RESET, AND CLOCKS
2-10
Seiko epson Corporation
S1C17F13 TeChniCal Manual
(Rev. 1.0)
OSC3BCLK
(Unstable)
OSC1CLK
(Unstable)
(1) When the CLGOSC.OSC1SLPC bit = 1
SYSCLK
(CPU operating clock)
SLEEP mode
(CPU stop, CLK stop)
Executing the
slp instruction
Interrupt
(Wake-up)
Oscillation stabilization waiting time
OSC3BCLK
OSC3BCLK
OSC3BCLK
(Unstable)
Timer
operating clock
(CLK stop)
∗
The timer is turned off in
SLEEP mode as the clock stops.
OSC1CLK
OSC1CLK
(2) When the CLGOSC.OSC1SLPC bit = 0
SYSCLK
(CPU operating clock)
SLEEP mode
(CPU stop, CLK stop)
Executing the
slp instruction
Interrupt
(Wake-up)
OSC3BCLK
OSC3BCLK
Timer
operating clock
∗
The timer continues operating in
SLEEP mode as the clock is being supplied.
OSC1CLK
3.4.2 Clock Control Example in SLEEP Mode
Figure 2.
The SYSCLK condition (clock source and division ratio) at wake-up from SLEEP mode to RUN mode can also
be configured. This allows flexible clock control according to the wake-up process. Configure the clock using
the CLGSCLK.WUPSRC[1:0] and CLGSCLK.WUPDIV[1:0] bits, and write 1 to the CLGSCLK.WUPMD bit
to enable this function.
(1) When the CLGSCLK.WUPMD bit = 0
SYSCLK
(CPU operating clock)
SLEEP mode
(CPU stop, CLK stop)
Executing the
slp instruction
Interrupt
(Wake-up)
OSC3BCLK
OSC3BCLK
∗
Starting up with the same clock as one
that used before SLEEP mode was entered.
(2) When the CLGSCLK.WUPMD bit = 1 and the CLGSCLK.WUPSRC[1:0] bits = 0x0
SYSCLK
(CPU operating clock)
SLEEP mode
(CPU stop, CLK stop)
Executing the
slp instruction
Interrupt
(Wake-up)
OSC1CLK
OSC3BCLK
∗
Switching to OSC3B that features fast
initiation allows high-speed processing.
OSC3BCLK
(Unstable)
Oscillation stabilization waiting time
OSC3BCLK
(Unstable)
CLGSCLK.CLKSRC[1:0] = 0x1 (OSC1)
CLGSCLK.WUPSRC[1:0] = 0x0 (OSC3B)
CLGSCLK.CLKSRC[1:0] = 0x0 (OSC3B)
CLGSCLK.WUPSRC[1:0] = 0x0 (OSC3B)
CLGSCLK.CLKSRC[1:0] = 0x0 (OSC3B)
CLGSCLK.WUPSRC[1:0] = 0x0 (OSC3B)
3.4.3 Clock Control Example at SLEEP Cancelation
Figure 2.
Note: When OSC1 (OSC1A or OSC1B) is configured to stop in SLEEP mode (CLGOSC.OSC1SLPC
bit = 1), executing the slp instruction while a timer is running with OSC1 as the clock source will
destabilize the timer operation at restarting from SLEEP mode. When switching to SLEEP mode
with CLGOSC.OSC1SLPC bit set to 1, stop the timer before executing the slp instruction. It is
not necessary to stop the timer when OSC1 is configured to operate in SLEEP mode.
Clock external output (FOUT)
The FOUT pin can output the clock generated by a clock source or its divided clock to outside the IC. This al-
lows monitoring the oscillation frequency of the oscillator circuit or supplying an operating clock to external
ICs. Follow the procedure shown below to start clock external output.
1. Assign the FOUT function to the port.
(Refer to the “I/O Ports” chapter.)
2. Configure the following CLGFOUT register bits:
- CLGFOUT.FOUTSRC[1:0] bits
(Select clock source)
- CLGFOUT.FOUTDIV[2:0] bits
(Set clock division ratio)
- Set the CLGFOUT.FOUTEN bit to 1. (Enable clock external output)