CHAPTER 5 CLOCK GENERATOR
Preliminary User’s Manual U16846EJ1V0UD
97
A status transition diagram of this product is shown in Figure 5-14, and the relationship between the operation
clocks in each operation status and between the oscillation control flag and oscillation status of each clock are shown
in Tables 5-3 and 5-4, respectively.
Figure 5-14. Status Transition Diagram (1/2)
(1) When “Ring-OSC can be stopped by software” is selected by option byte
Status 4
CPU clock: f
XP
f
XP
: Oscillating
f
R
: Oscillation stopped
Status 3
CPU clock: f
XP
f
XP
: Oscillating
f
R
: Oscillating
Status 1
CPU clock: f
R
f
XP
: Oscillation stopped
f
R
: Oscillating
Status 2
CPU clock: f
R
f
XP
: Oscillating
f
R
: Oscillating
HALT
Note 4
Interrupt
Interrupt
Interrupt
Interrupt
Interrupt
Interrupt
Reset release
Interrupt
Interrupt
HALT
instruction
STOP
instruction
STOP
instruction
STOP
instruction
STOP
instruction
RSTOP = 0
RSTOP = 1
Note 1
MCM0 = 0
MCM0 = 1
Note 2
MSTOP = 1
Note 3
MSTOP = 0
HALT
instruction
HALT instruction
HALT
instruction
STOP
Note 4
Reset
Note 5
Notes 1. When shifting from status 3 to status 4, make sure that bit 1 (MCS) of the main clock mode register
(MCM) is 1.
2. Before shifting from status 2 to status 3 after reset and STOP are released, check the high-speed
system clock oscillation stabilization time status using the oscillation stabilization time counter status
register (OSTC).
Waiting for the oscillation stabilization time is not required when the external RC oscillation clock is
selected as the high-speed system clock by the option byte. Therefore, the CPU clock can be
switched without reading the OSTC value.
3. When shifting from status 2 to status 1, make sure that MCS is 0.
4. When “Ring-OSC can be stopped by software” is selected by the option byte, the watchdog timer
stops operating in the HALT and STOP modes, regardless of the source clock of the watchdog timer.
However, oscillation of Ring-OSC does not stop even in the HALT and STOP modes if RSTOP = 0.
5. All reset sources (RESET input, POC, LVI, clock monitor, and WDT)