NEC PD78058FY(A) User Manual

Page 518

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518

CHAPTER 23 STANDBY FUNCTION

HALT
Instruction

Interrupt
Request

Wait

Standby
Release Signal

Operating
Mode

Clock

HALT Mode

Wait

Oscillation

Operating Mode

(2) HALT mode clear

The HALT mode can be cleared with the following four types of sources.

(a) Clear upon unmasked interrupt request

The HALT mode is cleared when an unmasked interrupt request is generated. If interrupt acknowledge

is enabled, vectored interrupt servicing is performed. If disabled, the next address instruction is executed.

Figure 23-2. HALT Mode Clear upon Interrupt Request Generation

Remarks 1. The broken line indicates the case when the interrupt request which has cleared the standby

status is acknowledged.

2. Wait time will be as follows:

• When vectored interrupt service is carried out:

8 to 9 clocks

• When vectored interrupt service is not carried out:

2 to 3 clocks

(b) Clear upon non-maskable interrupt request

When an unmasked interrupt request is generated, the HALT mode is cleared and vectored interrupt

servicing is performed whether interrupt acknowledge is enabled or disabled.

(c) Clear upon unmasked test input

The HALT mode is cleared by unmasked test input and the next address instruction of the HALT instruction

is executed.

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