HD404818 Datasheet, PDF (32/100 Pages) Hitachi Semiconductor – 16-digit LCD driver

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HD404818 Series
Stop Mode: The MCU enters stop mode if the STOP instruction is executed in active mode when TMA3 =
0. In this mode, the system oscillator stops, which stops all MCU functions as well.
Stop mode is terminated by a RESET input as shown in figure 11. RESET must be high for at least one t_RC
to stabilize oscillation (refer to the AC Characteristics section). When the MCU restarts after stop mode is
cancelled, all RAM contents are retained, but the accuracy of the contents of the accumulator, B register, W
register, X/SPX register, Y/SPY register, carry flag, and serial data register cannot be guaranteed.
Oscillator
Internal clock
Stop mode
RESET
STOP instruction execution
t _res
t_res ≥ t_RC (stabilization time)
Figure 11 Timing of Stop Mode Cancellation
Watch Mode: The MCU enters watch mode if the STOP instruction is executed in active mode when
TMA3 = 1, or if the STOP or SBY instruction is executed in subactive mode.
Watch mode is terminated by a RESET input or a timer-A/INT₀ interrupt request. For details on RESET
input, refer to the Stop Mode section. When terminated by a timer-A/INT₀ interrupt request, the MCU
enters active mode if LSON is 0, or subactive mode if LSON is 1. After an interrupt request is generated,
the time required to enter active mode is t_RC for a timer A interrupt, and T_X (where T + t_RC ≤ T_X ≤ 2T + t_RC)
for an INT₀ interrupt, as shown in figure 12.
Operation during mode transition is the same as that at standby mode cancellation (figure 10).
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