IA186ER/IA188ER
Data Sheet
16-Bit/8-Bit Microcontrollers with RAM
February 25, 2013
Six external interrupt sources—five maskable (int4–int0) and one nonmaskable (NMI)—are
connected to the processor and six internal interrupt sources (three timers, two DMA channels,
and the asynchronous serial port that are not brought out to external pins).
The five external maskable interrupt request pins can be used as direct interrupt requests.
However, should more interrupts be needed, int3–int0 may be used with the 82C59A-compatible
external interrupt controller. By programming the internal interrupt controller to slave mode, an
82C59A-compatible external interrupt controller can be used as the system master. Interrupt
nesting can be used in all cases that permit interrupts of a higher priority to interrupt those of a
lower priority.
When an interrupt is accepted, other interrupts are disabled, but may be re-enabled by setting the
Interrupt Enable Flag (IF) in the Processor Status Flags register during the Interrupt Service
Routine (ISR). Setting IF permits interrupts of equal or greater priority to interrupt the currently
running ISR.
Further interrupts from the same source will be blocked until the corresponding bit in the
In-Service register (INSERV) is cleared. Special Fully Nested mode (SFNM) is invoked for int0
and int1 by the SFNM bit in the INT0 and INT1 control register, respectively, when this bit is set
to 1. In this mode, a new interrupt may be generated by these sources regardless of the in-service
bit. The following table shows the priorities of the interrupts at POR.
4.16.1 Interrupt Types
Table 14 presents interrupt names, types, vector table address, End-of-Interrupt (EOI) type,
overall priority, and related instructions.
Table 14. Interrupt Types
Interrupt Vector Table
Overall
Priority
1
1A
1B
1
Related
Instructions
DIV, IDIV
All
Interrupt Name
Type
00h
01h
02h
03h
04h
05h
06h
Address
EOI Type
NA
a
00h
Divide Error Exception
b
04h
NA
Trace Interrupt
Non-maskable Interrupt (NMI)
08h
0ch
NA
NA
–
a
INT3
INT0
BOUND
Breakpoint Interrupt
a
10h
NA
1
INT0 Detected Overflow Exception
a
14h
NA
1
Array Bounds Exception
a
18h
NA
1
Undefined
Opcodes
Unused Opcode Exception
a,c
07h
1ch
NA
1
ESC
Opcodes
ESC Opcode Exception
d,e
08h
12h
13h
20h
48h
4ch
08h
08h
08h
2A
2B
2C
–
–
–
Timer 0 Interrupt
d,e
Timer 1 Interrupt
d,e
Timer 2 Interrupt
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