CHAPTER 14 INTERRUPT FUNCTIONS
User’s Manual U14826EJ5V0UD
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14.3 Interrupt Function Control Registers
The interrupt functions are controlled by the following three types of registers.
• Interrupt request flag register 0 (IF0)
• Interrupt mask flag register 0 (MK0)
• Program status word (PSW)
Table 14-2 lists interrupt requests, the corresponding interrupt request flags, and interrupt mask flags.
Table 14-2. Interrupt Request Signals and Corresponding Flags
Interrupt Request Signal
Interrupt Request Flag
Interrupt Mask Flag
INTWDT
INTTM30
INTTM40
INTLVI1
INTEE0
TMIF4
TMIF30
TMIF40
LVIF1
EEIF0
TMMK4
TMMK30
TMMK40
LVIMK1
EEMK0
(1) Interrupt request flag register 0 (IF0)
An interrupt request flag is set to 1 when the corresponding interrupt request is issued, or when the
instruction is executed. It is cleared to 0 by executing an instruction when the interrupt request is
acknowledged or when a RESET signal is input.
IF0 is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input clears IF0 to 00H.
Figure 14-2. Format of Interrupt Request Flag Register 0
××
IF
×
0
1
Interrupt request flag
No interrupt request signal has been issued.
An interrupt request signal has been issued; an interrupt request status.
0
0
0
EEIF0
TMIF30
TMIF40
LVIIF1
TMIF4
IF0
7
6
5
<4>
<3>
<2>
<1>
<0>
Symbol
Address
After reset
R/W
FFE0H
00H
R/W
Cautions 1. Be sure to clear bits 5 to 7 to 0.
2. The TMIF4 flag can be read- and write-accessed only when the watchdog timer is being
used as an interval timer. It must be cleared to 0 if the watchdog timer is used in
watchdog timer mode 1 or 2.
3. When an interrupt is acknowledged, the interrupt request flag is automatically cleared
and then the interrupt routine is started.