CHAPTER 14 INTERRUPT FUNCTIONS
User’s Manual U14826EJ5V0UD
140
(2) Interrupt mask flag register 0 (MK0)
The interrupt mask flag is used to enable and disable the corresponding maskable interrupts.
MK0 is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets MK0 to FFH.
Figure 14-3. Format of Interrupt Mask Flag Register 0
××
MK
×
0
1
Interrupt servicing control
Enables servicing servicing.
Disables servicing servicing.
1
1
1
EEMK0
TMMK30
TMMK40
LVIMK1
TMMK4
MK0
7
6
5
<4>
<3>
<2>
<1>
<0>
Symbol
Address
After reset
R/W
FFE4H
FFH
R/W
Cautions 1. Be sure to set bits 5 to 7 to 1.
2. The TMMK4 flag can be read- and write-accessed only when the watchdog timer is
being used as an interval timer.
(3) Program status word (PSW)
The program status word is used to hold the instruction execution result and the current status of the interrupt
requests. The IE flag, used to enable and disable maskable interrupts, is mapped to PSW.
PSW can be read- and write-accessed in 8-bit units, as well as using bit manipulation instructions and
dedicated instructions (EI and DI). When a vectored interrupt is acknowledged, the PSW is automatically
saved to a stack, and the IE flag is reset to 0.
RESET input sets PSW to 02H.
Figure 14-4. Program Status Word Configuration
IE
Z
0
AC
0
0
1
CY
PSW
Symbol
After reset
02H
7
6
5
4
3
2
1
0
IE
0
1
Disabled
Enabled
Whether to enable/disable interrupt acknowledgment
Used in the execution of ordinary instructions
Содержание PD789860
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