HD404369 Datasheet, PDF (32/115 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer

HD404369 Series
frame timing, but it is regarded as input synchronously with the second interrupt strobe clock after the
falling edge. An overflow and interrupt request in timer A is generated synchronously with the interrupt
strobe timing.
Active mode
Watch mode
Oscillation
stabilization period
Active mode
Interrupt strobe
INT₀
Interrupt request
generation
(During the transition
T
from watch mode to
active mode only)
T: Interrupt frame length
t_RC : Oscillation stabilization period
T
t_RC
T_X
T + t_RC ≤ T_X ≤ 2T + t_RC
Figure 14 Interrupt Frame
Direct Transition from Subactive Mode to Active Mode: Available by controlling the direct transfer on
flag (DTON: $020, bit 3) and the low speed on flag (LSON: $020, bit 0). The procedures are described
below:
• Set LSON to 0 and DTON to 1 in subactive mode.
• Execute the STOP or SBY instruction.
• The MCU automatically enters active mode from subactive mode after waiting for the MCU internal
processing time and oscillation stabilization time (figure 16).
Notes: 1. The DTON flag ($020, bit 3) can be set only in subactive mode. It is always reset in active
mode.
2. The transition time (T_D) from subactive mode to active mode:
t_RC < T_D < T + t_RC
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