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5.2.5
IRQ Status Register (ISR)
Bit
:
IRQ7F
Initial value
:
R/W
:
R/(W)*
Note: * Only 0 can be written, to clear the flag.
ISR is an 8-bit readable/writable register that indicates the status of IRQ7 to IRQ0 interrupt
requests.
ISR is initialized to H'00 by a reset and in hardware standby mode.
They are not initialized in software standby mode.
Bits 7 to 0—IRQ7 to IRQ0 flags (IRQ7F to IRQ0F): These bits indicate the status of IRQ7 to
IRQ0 interrupt requests.
Bit n
IRQnF
Description
0
[Clearing conditions] (Initial value)
•
Cleared by reading IRQnF flag when IRQnF = 1, then writing 0 to IRQnF flag
•
When interrupt exception handling is executed when low-level detection is set
(IRQnSCB = IRQnSCA = 0) and IRQn input is high
•
When IRQn interrupt exception handling is executed when falling, rising, or both-edge
detection is set (IRQnSCB = 1 or IRQnSCA = 1)
•
When the DTC is activated by an IRQn interrupt, and the DISEL bit in MRB of the
DTC is cleared to 0
1
[Setting conditions]
•
When IRQn input goes low when low-level detection is set (IRQnSCB = IRQnSCA =
0)
•
When a falling edge occurs in IRQn input when falling edge detection is set
(IRQnSCB = 0, IRQnSCA = 1)
•
When a rising edge occurs in IRQn input when rising edge detection is set
(IRQnSCB = 1, IRQnSCA = 0)
•
When a falling or rising edge occurs in IRQn input when both-edge detection is set
(IRQnSCB = IRQnSCA = 1)
98
7
6
IRQ6F
IRQ5F
0
0
R/(W)*
R/(W)*
5
4
IRQ4F
IRQ3F
0
0
R/(W)*
R/(W)*
3
2
IRQ2F
IRQ1F
0
0
R/(W)*
R/(W)*
1
0
IRQ0F
0
0
R/(W)*
(n = 5 to 0)
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