Oscillation Stabilization Wait Time - Fujitsu FR60 Hardware Manual

3.9.4

Oscillation Stabilization Wait Time

If a device returns from the state in which the original oscillation was or may have been
stopped, the device automatically enters the oscillation stabilization wait state. This
function prevents the use of oscillator output after starting before oscillation has
stabilized.
For the oscillation stabilization wait time, neither an internal nor an external clock is
supplied; only the built-in timebase counter runs until the stabilization wait time set in
the standby control register (STCR) has elapsed.
This section describes the oscillation stabilization wait operation.
■ Sources of an Oscillation Stabilization Wait
The following lists sources of an oscillation stabilization wait.
●
Clearing of a settings initialization reset (INIT)
The device enters the oscillation stabilization wait state if a settings initialization reset (INIT) is cleared for
a variety of reasons.
When the oscillation stabilization wait time has elapsed, the device enters the operation initialization reset
(RST) state.
For initialization that uses the INIT pin, since the oscillation stabilization wait time is set to the minimum
value, there is no wait for oscillation stabilization. When power-on is executed or after oscillation has
stopped, input an oscillation stabilization wait time INIT.
●
Returning from stop mode
The device enters the oscillation stabilization wait state immediately after stop mode is cleared.
However, if it is cleared by a settings initialization reset (INIT) request, the device enters the settings
initialization reset (INIT) state. Then, after the settings initialization reset (INIT) is cleared, the device
enters the oscillation stabilization wait state.
When the oscillation stabilization wait time has elapsed, the device enters the state corresponding to the
source that cleared stop mode:
• Return due to input of a valid external interrupt request (including NMI) and occurrence of a watch
timer/main clock oscillation stabilization wait timer interrupt: The device enters the normal operating
state.
• Return due to a settings initialization reset (INIT) request: The device enters the operation initialization
reset (RST) state.
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