2-18
Seiko Epson Corporation
S1C31D50 TECHNICAL MANUAL
(Rev. 1.00)
2.4.
Operating Mode
2.4.1.
Initial Boot Sequence
Figure 2.4.1.1 shows the initial boot sequence after power is turned on.
Figure 2.4.1.1 Initial Boot Sequence
Note:
The reset cancelation time at power-on varies according to the power rise time and reset request
cancelation time.
For the reset hold time t
RSTR
, refer to
“Reset hold
circuit
characteristics”
in the
“Electrical
Characteristics”
chapter.
2.4.2.
Transition between Operating Modes
State transitions between operating modes shown in Figure 2.4.2.1 take place in this IC.
RUN mode
RUN mode refers to the state in which the CPU is executing the program. A transition to this mode
takes place when the system reset request from the system reset controller is canceled. RUN mode is
classified into
“IOSC
RUN,
” “OSC1
RUN,
” “OSC3
RUN,
” and “EXOSC
R
UN” by the SYSCLK clock source.
HALT mode
When the Cortex
®
-M0+ core executes the WFI or WFE instruction with the SLEEPDEEP bit of the
system control register set to 0, it suspends program execution and stops operating. This state is
referred to HALT mode in this IC. In this mode, the clock sources and peripheral circuits keep
operating. This mode can be set while no software processing is required and it reduces power
consumption as compared with RUN mode. HALT mode is classified into
“IOSC
HALT,
”
“OSC1
HALT,
”
“OSC3
HALT,
”
and
“EXOSC
HAL
T”
by the SYSCLK clock source.
Undefined
Undefined
*1
*2
V
DD
Reset request from POR
IOSCCLK
Internal reset signal
Cortex®-M0+ core
(Initial SYSCLK)
SYSRST, H0, H1
program counter (PC)
Cancel reset request
Reset hold time tRSTR
Cancel reset request
*1: Reset vector (reset handler start address)
*2: Address (reset 2)
Summary of Contents for S1C31D50
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