HD404019R Datasheet, PDF (39/65 Pages) Renesas Technology Corp – CMOS 4-bit single-chip microcomputers

HD404019R Series
Stop Mode: Executing the STOP instruction brings the MCU into stop mode, in which the oscillator circuit
and every function of the MCU stop.
The stop mode may be cancelled by resetting the MCU. At this time, as shown in figure 20, reset input
must be applied for at least t_RC for oscillation to be stabilized. (Refer to the AC Characteristics table.) After
the stop mode is cancelled, RAM retains the state it was in just before the MCU went into stop mode, but
the accumulator, B register, W register, X/SPX registers, Y/SPY registers, carry flag, and serial data
register will not retain their contents.
Oscillator
Stop mode
Internal clock
RESET
STOP instruction
execution
t_res
t_res ≥ t_RC (stabilization time)
Figure 20 Timing of Stop Mode Cancellation
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