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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
When an unmasked interrupt request is generated, the HALT mode is cleared. If interrupt request
acknowledge is enabled, vectored interrupt service is carried out. 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 a non-maskable interrupt request is generated, the HALT mode is cleared and vectored interrupt
service is carried out whether interrupt acknowledge is enabled or disabled.
(c) Clear upon unmasked test input
When an unmasked test signal is input, the HALT mode is cleared and the next address instruction of
the HALT instruction is executed.