R01UH0823EJ0100 Rev.1.00
Page 273 of 1823
Jul 31, 2019
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:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit
Symbol
Bit Name
Description
R/W
b7 to b0
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
Fast Interrupt Enable
0: Fast interrupt is disabled
1: Fast interrupt is enabled
R/W