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3.5 Resets
I
Main Clock Oscillation Stabilization Delay Time and the Reset Source
Whether there will be an oscillation stabilization delay time depends on the operating mode
when reset occurs, and the power-on reset option selected.
Following reset, operation always starts out in the normal main clock operating mode,
regardless of the kind of reset it was, or the operating mode (the clock mode and standby mode)
prior to reset. Therefore, if reset occurs while the main clock oscillator is stopped or in a
stabilization delay time, the system will be in a "main clock oscillation stabilization reset" state,
and a clock stabilization period will be provided. If the device is set for no power-on reset,
however, no main clock oscillation stabilization delay time is provided for power-on or external
reset.
In software or watchdog reset, if the reset occurs while the device is in main clock mode, no
stabilization time is provided. If it occurs in the subclock mode, however, a stabilization time is
provided since the main clock oscillation is stopped.Table 3.5-2 "Reset Source and Oscillation
Stabilization Delay Time" shows the relationships between the reset sources and the main clock
oscillation stabilization delay time, and reset mode (mode fetch) operations.
Table 3.5-2 Reset Source and Oscillation Stabilization Delay Time
Reset source
Operating state
Reset operation and main clock oscillation stabilization delay time
External
reset
*1
At power on,
during stop mode,
or subclock mode
After the main clock oscillation stabilization delay time, if the external
reset is waked up, reset is operated.
*2
Software and
watchdog
reset
Main clock mode
After 4-instruction-cycle reset occurs, reset is operated.
*3
Subclock mode
Reset is operated after the main clock oscillation stabilization delay
time.
*2
Power-on reset
Device enters main clock oscillation stabilization delay time at power
on. Reset is operated after delay time ends.
*2
*1: No oscillation stabilization delay time is required for external reset while main clock mode is operating.
Reset is operated after external reset is waked up.
*2: If the reset output option is selected, "L" is output at RSTX pin during the main clock oscillation
stabilization delay time.
*3: If the reset output option is selected, "L" level is output at RSTX pin during 4-instruction-cycle.