User's Manual

Table Of Contents
R01UH0823EJ0110 Rev.1.10 Page 303 of 1852
Nov 30, 2020
RX23W Group 15. Interrupt Controller (ICUb)
Figure 15.3 to Figure 15.6 show the interrupt signals of the interrupt controller. Note that the timings of the interrupts
with interrupt vector numbers 64 to 95 are different from those of other interrupts. For the IRQ pin interrupts with
interrupt vector numbers 64 to 79, “internal delay + 2 PCLK cycles” of delay is added after the IRQ pin input. For the
interrupts with interrupt vector numbers 80 to 95, “2 PCLK cycles” of delay is added.
If an interrupt signal is generated every clock cycle, the subsequent interrupts cannot be detected; secure two or more
clock cycles of the system clock or peripheral module clock, whichever is slower, between issuance of continuous
interrupt requests.
Figure 15.3 Interval Required between Issuance of Continuous Interrupt Requests (when the Frequency of
System Clock is Slower than that of the Peripheral Module Clock)
While the IRn.IR flag is 1 after an interrupt request is generated, the interrupt request that is generated again will be
ignored.*
1
Figure 15.4 shows the timing for IRn.IR flag re-setting.
Note 1. When the transmission or reception interrupt of the SCI, RSPI, RIIC, USB, SSI, SDHI, or RSCAN is generated
with the IRn.IR flag being 1, the interrupt request is retained. After the IRn.IR flag is cleared to 0, the IRn.IR flag
is set to 1 again by the retained request. For details, see descriptions of the interrupts in section 33, Serial
Communications Interface (SCIg, SCIh), section 35, I
2
C-bus Interface (RIICa), and section 38, Serial Peripheral
Interface (RSPIa).
Figure 15.4 Timing for IRn.IR Flag Re-Setting
If an interrupt is disabled after the IRn.IR flag is set to 1 (output of the interrupt request is disabled by the interrupt enable
bit of the relevant peripheral module), the IRn.IR flag is not affected but retains its state. Figure 15.5 shows operation
when the interrupt is disabled.
Figure 15.5 Relationship between IRn.IR Flag Operation and Disabling of Interrupt Request
System clock
Interrupt signal
IRn.IR flag
Peripheral module clock
At least two system
clock cycles
(1) (2) (3)
Interrupt acceptance
(1)
Interrupt signal
IRn.IR flag
Interrupt acceptance
(3)
An interrupt request (2) is ignored while the IR flag in IRn is 1.
Interrupt signal
IRn.IR flag
IRn.IR flag is not cleared even when the source is disabled
Interrupt request is enabled/disabled
Enabled
Disabled