Filter
Top Products
44
CHAPTER 3 CPU
● Power-on reset
Power-on reset occurs when power is turned on. Power-on reset occurs after oscillation stabilization wait
time has expired.
Power-on reset requires an external reset circuit.
■
Reset Sources and Oscillation Stabilization Wait Time
Operations in oscillation stabilization wait time depend on the operating mode used when a reset occurs.
After a reset, active mode is set regardless of the operating mode applied before the reset (standby mode)
and reset source. Therefore, if a reset occurs while oscillation is being stopped or within the oscillation
stabilization wait time, the oscillation stabilization wait reset mode is set.
Software reset and watchdog reset do not apply oscillation stabilization wait time.
Table 3.5-2 shows the relationship between reset sources, oscillation stabilization wait time, and the reset
operation (mode fetch).
Table 3.5-2 Relationship between the Reset Sources and Oscillation Stabilization Wait Time
Reset source Operating mode Reset operation and oscillation stabilization wait time
External reset
*
When power is
turned on or stop
mode
The reset operation is performed when external reset is cancelled after
oscillation stabilization wait time has expired.
Software reset and
watchdog reset
Active mode
The reset operation is performed following the generation of a 4-
instruction cycle reset.
Power-on reset
When power is
turned on
The reset operation is performed after power is turned on and
oscillation stabilization wait time has expired.
* External reset in active mode does not apply oscillation stabilization wait time. The reset operation is performed after
cancellation of external reset.