NEC uPD78P078 - Manual (Page 548)

548
CHAPTER 24 STANDBY FUNCTION
(2) HALT mode release
The HALT mode can be released with the following four types of sources.
(a) Release by unmasked interrupt request
An unmasked interrupt request is generated to release the HALT mode. If interrupt request acknowledge
is enabled, vectored interrupt service is carried out. If disabled, the next address instruction is executed.
Figure 24-2. HALT Mode Released by Interrupt Request Generation
Remarks 1. The broken line indicates the case when the interrupt request which has released 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) Release by non-maskable interrupt request
The HALT mode is released and vectored interrupt service is carried out if non-maskable interrupt
request is generated whether interrupt request acknowledge is enabled or disabled.
(c) Release by unmasked test input
The HALT mode is released by inputting an unmasked test signal and the next address instruction of
the HALT instruction is executed.
HALT
Instruction
Interrupt Request
Wait
Standby
Release Signal
Operating
Mode
Clock
HALT Mode Wait
Oscillation
Operating Mode