M38203M4 Datasheet, PDF (263/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.9 Standby function
(2) Release of stop mode
The stop mode is released by reset input or by the occurrence of an interrupt request.
There is a difference in restore processing from the stop mode by reset input and by an interrupt
request.
sRestoration by reset input
By holding the “L” input level of the RESET pin in the stop mode for 2 µs or more, the reset state
is set, so that the stop mode is released.
At the time when the stop mode is released, oscillation is started. At this time, the inside of the
microcomputer is in the reset state. After the input level of the RESET pin is returned to the “H,” the
reset state is released in approximately 8,000 cycles of the XIN input.
The oscillation is unstable at start of oscillation. For this reason, time for stabilizing of oscillation
(oscillation stabilizing time) is required. The time to hold the internal reset state is reserved as the
oscillation stabilizing time.
Figure 2.9.1 shows the oscillation stabilizing time at restoration by reset input.
At release of the stop mode, the contents of the internal RAM previous to the reset are held.
However, the contents of the CPU register and SFR are not held.
For resetting, refer to “2.10 Reset.”
Stop mode
Time to hold internal reset state =
approximately 8000 cycles of XIN
input
Oscillation stabilizing time
VCC
RESET
2 µ s or more
XIN
(Note)
Execute STP instruction Restored by reset input
Note: No waveform may be input to XIN (in low-speed mode)
Fig. 2.9.1 Oscillation stabilizing time at restoration by reset input
3820 GROUP USER’S MANUAL
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