R01UH0823EJ0100 Rev.1.00
Page 270 of 1823
Jul 31, 2019
RX23W Group
15. Interrupt Controller (ICUb)
15.2
Register Descriptions
15.2.1
Interrupt Request Register n (IRn) (n = interrupt vector number)
Note 1. For an edge detection interrupt, only 0 can be written to this bit; do not write 1.
For a level detection interrupt, neither 0 nor 1 can be written.
IRn is provided for each interrupt source, where “n” indicates the interrupt vector number.
For the correspondence between interrupt sources and interrupt vector numbers, see
IR Flag (Interrupt Status Flag)
This flag is the status flag of an individual interrupt request. This flag is set to 1 when the corresponding interrupt request
is generated. To detect an interrupt request, the interrupt request output should be enabled by the corresponding
peripheral module interrupt enable bit.
There are two interrupt request detection methods: edge detection and level detection. For interrupts from peripheral
modules, either edge detection or level detection is determined per interrupt source. For interrupts from IRQi (i = 0, 1,
and 4 to 7) pins, edge detection or level detection is selected by setting the corresponding IRQCRi.IRQMD[1:0] bits. For
detection of the various interrupt sources, see
Table 15.3, Interrupt Vector Table
.
(1) Edge detection
[Setting condition]
The flag is set to 1 in response to the generation of an interrupt request from the corresponding peripheral module or
IRQi pin. For interrupt generation by the various peripheral modules, refer to the sections describing the modules.
[Clearing conditions]
The flag is cleared to 0 when the interrupt request destination accepts the interrupt request.
The IR flag is cleared to 0 by writing 0 to it. Note, however, that writing 0 to the IR flag is prohibited if the
destination of the interrupt request is the DTC or DMAC.
(2) Level detection
[Setting condition]
The flag remains set to 1 while an interrupt request is being sent from the corresponding peripheral module or IRQi
pin. For interrupt generation by the various peripheral modules, refer to the sections describing the modules.
[Clearing condition]
The flag is cleared to 0 when the source of the interrupt request is cleared (it is not cleared when the interrupt
request destination accepts the interrupt request). For clearing interrupts from the various peripheral modules, refer
to the sections describing the modules.
When level detection has been selected for an IRQi pin, the interrupt request is withdrawn by driving the IRQi pin high.
Do not write 0 or 1 to the IR flag while level detection is selected.
Address(es): ICU.IR016 0008 7010h to ICU.IR255 0008 70FFh
b7
b6
b5
b4
b3
b2
b1
b0
—
—
—
—
—
—
—
IR
Value after reset:
0
0
0
0
0
0
0
0
Bit
Symbol
Bit Name
Description
R/W
b0
Interrupt Status Flag
0: No interrupt request is generated
1: An interrupt request is generated
R/(W)
*
b7 to b1
—
Reserved
These bits are read as 0. The write value should be 0.
R/W