310
CHAPTER 18 INTERRUPT FUNCTIONS
User
’
s Manual U14701EJ3V0UD
(1) Interrupt request flag registers (IF0L, IF0H, IF1L)
The interrupt request flags are set to 1 when the corresponding interrupt request is generated or an instruction
is executed. They are cleared to 0 when an instruction is executed upon acknowledgment of an interrupt request
or upon application of RESET input.
IF0L, IF0H, and IF1L are set by a 1-bit or 8-bit memory manipulation instruction. When IF0L and IF0H are
combined to form 16-bit register IF0, they are set by a 16-bit memory manipulation instruction.
RESET input sets the values of these registers to 00H.
Figure 18-2. Interrupt Request Flag Registers (IF0L, IF0H, IF1L) Format
Address: FFE0H After reset: 00H R/W
Symbol
7
6
5
4
3
2
1
0
IF0L
KRIF
PIF5
PIF4
PIF3
PIF2
PIF1
PIF0
WDTIF
Address: FFE1H After reset: 00H R/W
Symbol
7
6
5
4
3
2
1
0
IF0H
TMIF01
TMIF00
WTNIIF0
CSIIF3
CSIIF1
STIF0
SRIF0
SERIF0
Address: FFE2H After reset: 00H R/W
Symbol
7
6
5
4
3
2
1
0
IF1L
0
0
WTNIF0
ADIF0
TMIF52
TMIF51
TMIF50
TMIF4
XXIFX
Interrupt request flag
0
No interrupt request signal is generated
1
Interrupt request signal is generated, interrupt request status
Cautions 1. The WDTIF flag is R/W enabled only when the watchdog timer is used as the interval timer.
If watchdog timer mode 1 is used, set the WDTIF flag to 0.
2. Be sure to set bits 6 and 7 of IF1L to 0.
3. When operating a timer, serial interface, or A/D converter after standby release, run it once
after clearing an interrupt request flag. An interrupt request flag may be set by noise.
4. When an interrupt is acknowledged, the interrupt request flag is automatically cleared and
then the interrupt routine is started.