CHAPTER 14 INTERRUPT FUNCTIONS
276
User’s Manual U15075EJ1V0UM00
Figure 14-15. Example of Multiple Interrupts
Example 1. Acknowledging multiple interrupts
INTyy
EI
Main servicing
EI
INTyy servicing
INTxx servicing
RETI
IE = 0
INTxx
RETI
IE = 0
The interrupt request INTyy is acknowledged during the servicing of interrupt INTxx and multiple interrupts are
performed. Before each interrupt request is acknowledged, the EI instruction is issued and the interrupt request is
enabled.
Example 2. Multiple interrupts are not performed because interrupts are disabled
INTyy
EI
Main servicing
RETI
INTyy servicing
INTxx servicing
IE = 0
INTxx
RETI
INTyy is held pending
IE = 0
Because interrupt requests are disabled (the EI instruction has not been issued) in the interrupt INTxx servicing,
the interrupt request INTyy is not acknowledged and multiple interrupts are not performed. INTyy is held pending
and is acknowledged after INTxx servicing is completed.
IE = 0: Interrupt requests disabled
Содержание mPD789426 Series
Страница 2: ...2 User s Manual U15075EJ1V0UM00 MEMO...
Страница 6: ...6 User s Manual U15075EJ1V0UM00 MEMO...
Страница 10: ...10 User s Manual U15075EJ1V0UM00 MEMO...
Страница 24: ...24 User s Manual U15075EJ1V0UM00 MEMO...
Страница 36: ...36 User s Manual U15075EJ1V0UM00 MEMO...
Страница 46: ...46 User s Manual U15075EJ1V0UM00 MEMO...
Страница 176: ...User s Manual U15075EJ1V0UM00 176 MEMO...
Страница 196: ...User s Manual U15075EJ1V0UM00 196 MEMO...
Страница 210: ...User s Manual U15075EJ1V0UM00 210 MEMO...
Страница 262: ...262 User s Manual U15075EJ1V0UM00 MEMO...
Страница 278: ...278 User s Manual U15075EJ1V0UM00 MEMO...
Страница 296: ...296 User s Manual U15075EJ1V0UM00 MEMO...
Страница 298: ...User s Manual U15075EJ1V0UM00 298 MEMO...
Страница 316: ...User s Manual U15075EJ1V0UM00 316 MEMO...