CHAPTER 7 INTERRUPT AND TEST FUNCTIONS
211
User’s Manual U10676EJ3V0UM
(7) Enabling nesting of two interrupts - INTT0 and INT0 are nested doubly and INTBT and INTT2 are nested
singly -
Reset
INTBT
<1>
EI
EI
EI
EI
EI
IET0
IE0
IEBT
IET2
Status 0
Status 0
<lNTBT servicing program>
Status 0
Status 1
INTT0
<3>
RETI
<4>
Status 1
Status 0
EI
EI
RETI
<5>
IEBT
IET2
DI
CLR1
DI
DI
EI
<2>
IST0
IEBT
IET2
<lNTT0 servicing program>
<Main program>
<1> When an INTBT that does not enable nesting occurs, the INTBT servicing routine is started. The status
is 1.
<2> The status is changed to 0 by clearing IST0. INTBT and INTT2 that do not enable nesting are disabled.
<3> When an INTT0 that enables nesting occurs, nesting is executed. The status is changed to 1, and all
interrupts are disabled.
<4> The status is returned to 1 when INTT0 servicing is completed.
<5> The disabled INTBT and INTT2 are enabled, and execution returns to the main routine.
Содержание PD754144
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