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Reset sequence for operation initialization reset (RST)
This reset is generated by a software reset.
When the operation initialization reset (RST) request is cleared, the device performs the following steps
sequentially.
(1) Cancels the operation initialization reset (RST) and enters to the normal operating state.
(2) Reads a mode vector from address "000FFFF8
(3) Writes the mode vector to the MODR (mode register).
(4) Reads a reset vector from address "000FFFFC
(5) Writes the reset vector to the PC (program counter).
(6) Starts program operation from the address shown in the PC (program counter).
■ Oscillation Stabilization Wait Time
Upon returning from a state in which the device's source oscillation has been (seemingly) suspended, the
device enters the oscillation stabilization wait state automatically. This feature prevents the device from
using the oscillator output not yet stable after the start of oscillation.
During the oscillation stabilization wait time, the supply of clock signals to the internal and external
resources is stopped while only the internal timebase counter operates, waiting until the oscillation
stabilization wait time set in the STCR (standby control register) has passed.
The transition to the oscillation stabilization wait state is detailed below.
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Sources of transition to oscillation stabilization wait state
The transition to the oscillation stabilization wait state is caused as follows:
(1) Upon cancellation of a setting initialization reset (INIT)
Immediately after a setting initialization reset (INIT) is canceled by the sources, the device enters the
oscillation stabilization wait state.
When the oscillation stabilization wait time has passed, the device then enters the operation initialization
reset (RST) state.
Note that, after initialization via the INIT pin, the oscillation stabilization wait time is set to the minimum
value and thus the device does not wait for oscillation to become stable. Keep the oscillation stabilization
wait time using the input width of the INIT pin.
(2) Upon returning from the stop mode
Immediately after being released from the stop mode, the device enters the oscillation stabilization wait
state. If the device is released from it in response to a setting initialization reset (INIT) request, however,
the device enters the setting initialization reset (INIT) state instead. The device then enters the oscillation
stabilization wait state after the setting initialization reset (INIT) is canceled.
When the oscillation stabilization wait time has passed, the device then enters the state corresponding to the
source that canceled the stop mode:
•
When returning from stop mode in response to an effective external interrupt request input (including
an NMI)
→ The device enters to the normal operating state.
•
When returning from stop mode in response to a setting initialization reset (INIT) request
→ The device enters the setting initialization reset (INIT) state.
(3) Upon returning from an abnormal state with the PLL selected
CHAPTER 3 CPU AND CONTROL UNITS
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