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User’s Manual U19780EJ2V0UD
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CHAPTER 18 INTERRUPT FUNCTIONS
18.1 Interrupt Function Types
The following two types of interrupt functions are used.
(1) Maskable
interrupts
These interrupts undergo mask control. Maskable interrupts can be divided into a high interrupt priority group
and a low interrupt priority group by setting the priority specification flag registers (PR0L, PR0H, PR1L, PR1H).
Multiple interrupt servicing can be applied to low-priority interrupts when high-priority interrupts are generated. If
two or more interrupt requests, each having the same priority, are simultaneously generated, then they are
processed according to the priority of vectored interrupt servicing. For the priority order, see
Table 18-1
.
A standby release signal is generated and STOP and HALT modes are released.
External interrupt requests and internal interrupt requests are provided as maskable interrupts.
(2) Software
interrupt
This is a vectored interrupt generated by executing the BRK instruction. It is acknowledged even when interrupts
are disabled. The software interrupt does not undergo interrupt priority control.
18.2 Interrupt Sources and Configuration
The interrupt sources consist of maskable interrupts and software interrupts. In addition, they also have up to four
reset sources (see
Table 18-1
).