NEC PD750004 User Manual page 223

(1) Interrupt enable/disable
<1> A RESET signal disables all interrupts.
<2> Interrupt enable flags are set by the EI IExxx instruction. At this stage, all interrupts are disabled.
<3> The interrupt master enable flag is set by the EI instruction. At this stage, INT0 and INTT0 are
enabled.
<4> An interrupt enable flag is cleared by the DI IExxx instruction to disable INT0.
<5> The DI instruction disables all interrupts.
<Main program>
<1> Reset
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<2> EI IE0
EI IET0
<3> EI
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<4> DI IE0
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<5> DI
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CHAPTER 6 INTERRUPT AND TEST FUNCTIONS
Interrupt disabled
INT0 and INTT0 enabled
INTT0 enabled
Interrupt disabled
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