Renesas H8S/2318 series, Hardware Manual

Page: 146 / 1121

Rev. 5.00, 12/03, page 116 of 1088
5.2.5 IRQ Status Register (ISR)
Bit : 7 6 5 4 3 2 1 0
IRQ7F IRQ6F IRQ5F IRQ4F IRQ3F IRQ2F IRQ1F IRQ0F
Initial value : 0 0 0 0 0 0 0 0
R/W : R/(W)
*
R/(W)
*
R/(W)
*
R/(W)
*
R/(W)
*
R/(W)
*
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.
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)
(n = 7 to 0)