NEC PD75402A Manuale Utente

(1)

When the standby mode was reset by RESET input, normal reset operation is executed. (STOP and HALT modes)

(2)

When the standby mode was reset by interrupt request generation, whether or not a vector interrupt is executed

when the CPU resumes instruction execution is determined by the contents of the interrupt master enable flag

(IME). (HALT mode)

After HALT mode reset, execution is resumed from the instruction (NOP instruction) after the HALT mode

setting instruction.

The interrupt request flag is held.

After HALT mode is reset, a vector interrupt is executed two instructions after the HALT mode setting

instruction. However, because a vector interrupt is not generated when the HALT mode was reset by INT2

(testable input), the same processing as (a) is performed.

When using the standby mode, proceed as follows:

➀

Power interruption or other standby mode setting cause detection by interrupt input or port input.

➁

I/O port processing (Process for minimum current drain)

In particular, do not leave the input port open : be sure to input a low-level or high-level signal.

➂

Specification of interrupt which resets the standby mode (However, for HALT mode, interrupt enable flags

which is not reset are cleared.)

Specification of operation after reset (IME is operated according to whether or not interrupt processing

is performed after HALT mode resetting.)

➄

Specification of CPU clock after reset (For switching, provide the number of machine cycles necessary up

to standby mode setting.)

Standby mode setting (STOP and HALT instructions)

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