User's Manual

Table Of Contents
R01UH0823EJ0110 Rev.1.10 Page 281 of 1852
Nov 30, 2020
RX23W Group 15. Interrupt Controller (ICUb)
15.2.4 Fast Interrupt Set Register (FIR)
The fast interrupt function based on the FIR register setting is applicable only to interrupts to the CPU. It will not affect
any transfer request to the DTC or DMAC.
Before writing to this register, be sure to disable interrupt requests (IERm.IENj bit = 0 (m = 02h to 1Fh, j = 0 to 7)).
FVCT[7:0] Bits (Fast Interrupt Vector Number)
The FVCT[7:0] bits specify the vector number of an interrupt source that uses the fast interrupt function.
FIEN Bit (Fast Interrupt Enable)
This bit enables the fast interrupt.
Setting this bit to 1 makes the interrupt request of the vector number specified by the FVCT[7:0] bits a fast interrupt.
When an interrupt request of the vector number specified by the FVCT[7:0] bits is generated and the interrupt request
destination is the CPU while the FIEN bit is 1, the interrupt request is output to the CPU as a fast interrupt regardless of
the setting of the IPRn register (n = interrupt vector number). When using the fast interrupt for returning from the
software standby mode, see section 15.6.2, Return from Software Standby Mode.
If the setting of the IERm.IENj bit has disabled interrupt requests from the interrupt source with the vector number in this
register, fast interrupt requests are not output to the CPU.
For settable vector numbers, see Table 15.3, Interrupt Vector Table.
Do not write any reserved vector numbers to the FVCT[7:0] bits.
For details on the fast interrupt, see section 14, Exception Handling, and section 15.4.6, Fast Interrupt.
Address(es): ICU.FIR 0008 72F0h
b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
FIEN——————— FVCT[7:0]
Value after reset:
0000000000000000
Bit Symbol Bit Name Description R/W
b7 to b0 FVCT[7:0] Fast Interrupt Vector Number Specify the vector number of an interrupt source to be a fast
interrupt.
R/W
b14 to b8 Reserved These bits are read as 0. The write value should be 0. R/W
b15 FIEN Fast Interrupt Enable 0: Fast interrupt is disabled
1: Fast interrupt is enabled
R/W