HD404654 Datasheet, PDF (30/111 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404654 Series
MCU Operation Sequence: The MCU operates in the sequences shown in figures 14 to 16. It is reset by
an asynchronous RESET input, regardless of its status.
The low-power mode operation sequence is shown in figure 16. With the IE flag cleared and an interrupt
flag set together with its interrupt mask cleared, if a STOP/SBY instruction is executed, the instruction is
cancelled (regarded as an NOP) and the following instruction is executed. Before executing a STOP/SBY
instruction, make sure all interrupt flags are cleared or all interrupts are masked.
Power on
No
RESET = 0?
Yes
RAME = 0
Reset MCU
MCU
operation
cycle
Figure 14 MCU Operating Sequence (power on)
28