HD404669 Datasheet, PDF (39/142 Pages) Hitachi Semiconductor – Low-Voltage AS Microcomputers with On-Chip DTMF Generation Circuit

STOP/SBY
instruction
HD404669 Series
IF = 1 and
No
IM = 0?
Yes
No
Interrupt
service routine
IE = 0
Yes
Hardware NOP
execution
Standby/watch
mode
*
No
IF = 1 and
IM = 0?
Yes
Hardware NOP
execution
Stop mode
No
STOPC = 0?
Yes
RAME = 1
PC ← (PC)+1
PC ← (PC)+1
Reset MCU
Instruction
execution
MCU operation
cycle
Note: * Refer to figure 15, Flowchart for Exiting Low Power Modes,
for IF and IM operation.
Figure 20 MCU Operating (Low-Power Mode Operation)
Notes:
When the MCU is in watch mode or subactive mode, if the high level period before the falling
edge of INT₀ is shorter than the interrupt frame, INT₀ is not detected. Also, if the low level period
after the falling edge of INT₀ is shorter than the interrupt frame, INT₀ is not detected.
Edge detection is shown in figure 21. The level of the INT₀ signal is sampled by a sampling
clock. When this sampled value changes to low from high, a falling edge is detected.
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