M38203M4 Datasheet, PDF (284/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.11 Oscillation circuit
(2) Oscillation stabilizing time at restoration from the stop mode
In the stop mode, oscillation stops.
When restoration is made from the stop mode by reset input or an interrupt request, the oscillation
stabilizing time for approximately 8,000 cycles of XIN input or XCIN input is automatically generated as
at poweron.
At restoration made by reset, XIN input is a clock source of oscillation stabilizing time.
At restoration made by an interrupt request, either XIN input or XCIN input set as a system clock
immediately before execution of the STP instruction becomes a count source of oscillation stabilizing
time.
When XIN input is a system clock, the oscillation stabilizing time at restoration becomes approximately
8,000 cycles of XIN input. However, note that the oscillation on the XCIN side may not be stable even
after the lapse of this oscillation stabilizing time.
For the details of the stop mode, refer to “2.9.1 Stop mode.”
(3) Oscillation stabilizing time at reoscillation of XIN
When starting the oscillation of XIN which was stopped by setting the main clock (XIN–XOUT) stop bit
of the CPU mode register to “1,” set this bit to “0.” At this time, generate oscillation stabilizing time
by software.
Figure 2.11.7 shows the oscillation stabilizing time at reoscillation of XIN.
VCC
Main clock
(XIN–XOUT)
stop bit
XIN
Oscillation stabilizing time (Note)
Note: For oscillation stabilizing time, ask the resonator manufacturer for information.
Fig. 2.11.7 Oscillation stabilizing time at reoscillation of XIN
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3820 GROUP USER’S MANUAL