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CHAPTER 20 STANDBY FUNCTION
User’s Manual U19780EJ2V0UD
544
(b) Release by reset signal generation
When the reset signal is generated, HALT mode is released, and then, as in the case with a normal reset
operation, the program is executed after branching to the reset vector address.
Figure 20-4. HALT Mode Release by Reset
(1) When high-speed system clock is used as CPU clock
HALT
instruction
Reset signal
High-speed
system clock
(X1 oscillation)
HALT mode
Reset
period
Oscillates
Oscillation
stopped
Oscillates
Status of CPU
Normal operation
(high-speed
system clock)
Oscillation stabilization time
(2
11
/f
X
to 2
16
/f
X
)
Normal operation
(internal high-speed
oscillation clock)
Oscillation
stopped
Starting X1 oscillation is
specified by software.
Reset
processing
(11 to 45 s)
μ
(2) When internal high-speed oscillation clock is used as CPU clock
HALT
instruction
Reset signal
Internal high-speed
oscillation clock
Normal operation
(internal high-speed
oscillation clock)
HALT mode
Reset
period
Normal operation
(internal high-speed
oscillation clock)
Oscillates
Oscillation
stopped
Oscillates
Status of CPU
Wait for oscillation
accuracy stabilization
(86 to 361 s)
Reset
processing
(11 to 45 s)
μ
μ
(3) When subsystem clock is used as CPU clock
Note
HALT
instruction
Reset signal
Subsystem clock
(XT1 oscillation)
Normal operation
(subsystem clock)
HALT mode
Reset
period
Normal operation mode
(internal high-speed
oscillation clock)
Oscillates
Oscillation
stopped
Oscillates
Status of CPU
Oscillation
stopped
Starting XT1 oscillation is
specified by software.
Reset
processing
(11 to 45 s)
μ
Note
The 78K0/KB2 is not provided with a subsystem clock.
Remark
f
X
: X1 clock oscillation frequency