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CHAPTER 18 INTERRUPT FUNCTIONS
User
’
s Manual U14701EJ3V0UD
18.4.5 Interrupt request hold
There are instructions where, even if an interrupt request is issued for them while another instruction is executed,
request acknowledge is held pending until the end of execution of the next instruction. These instructions (interrupt
request hold instructions) are listed below.
MOV PSW, #byte
MOV A, PSW
MOV PSW, A
MOV1 PSW.bit, CY
MOV1 CY, PSW.bit
AND1 CY, PSW.bit
OR1 CY, PSW.bit
XOR1 CY, PSW.bit
SET1 PSW.bit
CLR1 PSW.bit
RETB
RETI
PUSH PSW
POP PSW
BT PSW.bit, $addr16
BF PSW.bit, $addr16
BTCLR PSW.bit, $addr16
EI
DI
Manipulate instructions for the IF0L, IF0H, IF1L, MK0L, MK0H, MK1L, PR0L, PR0H, and PR1L registers.
Caution The BRK instruction is not one of the above-listed interrupt request hold instructions. However,
the software interrupt activated by executing the BRK instruction causes the IE flag to be cleared
to 0. Therefore, even if a maskable interrupt request is generated during execution of the BRK
instruction, the interrupt request is not acknowledged. However, a non-maskable interrupt
request is acknowledged.
Figure 18-14 shows the timing with which interrupt requests are held pending.
Figure 18-14. Interrupt Request Hold
Remarks 1.
Instruction N: Interrupt request hold instruction
2.
Instruction M: Instruction other than interrupt request hold instruction
3.
The
××
PR (priority level) values do not affect the operation of
××
IF (interrupt request).
Instruction N
Instruction M
Save PSW and PC, jump
to interrupt servicing
Interrupt servicing
program
CPU processing
××
IF