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User’s Manual U12790EJ2V0UD
CHAPTER 18 INTERRUPT FUNCTIONS
18.1 Interrupt Function Types
The following three types of interrupt functions are used.
(1) Non-maskable interrupt
This interrupt is acknowledged unconditionally even if interrupts are disabled. It does not undergo interrupt
priority control and is given top priority over all other interrupt requests.
It generates a standby release signal.
One interrupt source from the watchdog timer is incorporated as a non-maskable interrupt.
(2) Maskable interrupts
These interrupts undergo mask control. Maskable interrupts can be divided into a high-priority interrupt group
and a low-priority interrupt group by setting the priority specification flag register (PR).
Multiple interrupt servicing can be applied to low-priority interrupts when high-priority interrupts are generated.
If two or more interrupts with the same priority are generated simultaneously, each interrupt is serviced
according to a predetermined priority (refer to Table 18-1).
A standby release signal is generated.
Maskable interrupts are provided in each product as follows.
PD178076, 178078
Internal: 13, external: 8
PD178096A, 178098A
Internal: 12, external: 8
PD178F098
Internal: 15, external: 8
(3) Software interrupt
This is a vectored interrupt generated by executing the BRK instruction. It is acknowledged even in an disabled
interrupt state. The software interrupt does not undergo interrupt priority control.
18.2 Interrupt Sources and Configuration
The
PD178076 and 178078 have a total of 22 interrupt sources, including non-maskable, maskable, and software
interrupts. The
PD178096A and 178098A have a total of 21 interrupt sources, and the PD178F098 has a total
of 24 sources.
Remark
Either a non-maskable interrupt or a maskable interrupt (internal) can be selected as the interrupt source
of the watchdog timer (INTWDT).