5
5-17
INTERRUPT CONTROLLER (ICU)
32180 Group User’s Manual (Rev.1.0)
Figure 5.5.2 Typical Handler Operation for Interrupts from Internal Peripheral I/O
5.5 Description of Interrupt Operation
Note 1: For operations at EIT acceptance and return from EIT, also see Section 4.3, "EIT Processing Procedure."
Note 2: Do not read the Interrupt Vector Register (IVECT) or write to the Interrupt Request Mask Register (IMASK)
in the EIT handler unless interrupts are disabled (PSW register IE bit = 0).
Note 3: When multiple interrupts are disabled, execute processing in [4]. Processing in [4] is unnecessary if multiple
interrupts are enabled by executing processing in [6] and [9].
Note 4: To enable multiple interrupts, execute processing in [6] and [9].
Note 5: To reenable interrupts (by setting the IE bit to 1) after reading the Interrupt Vector Register (IVECT),
perform a dummy access to the internal memory, etc. before reenabling interrupts. In the example here,
there is no need to add a dummy access because the ICU vector table is read after reading the IVECT register.
Similarly, to reenable interrupts (by setting the IE bit to 1) after writing to the Interrupt Request Mask Register
(IMASK), perform a dummy access to the internal memory, etc. before reenabling interrupts.
H'0000 0080
BRA instruction
Read Interrupt Vector
Register (IVECT)
Read ICU vector table
Branch to the interrupt handler
for each internal peripheral I/O
RTE
H'0080 0004
H'0000 0094
H'0000 0113
Interrupt
handler
EI (External Interrupt)
handler
EI (External Interrupt)
vector entry
Interrupt handler
start address
Program being
executed
Interrupt
generated
IVECT
Save BPC to the stack
Save PSW to the stack
Save general-purpose
registers to the stack
Restore BPC from the stack
Restore PSW from the stack
Restore general-purpose
registers from the stack
Read and save Interrupt
Request Mask Register
(IMASK) to the stack
IMASK
H'0080 0000
Set PSW register IE bit to 1
Clear PSW register
IE bit to 0
Restore Interrupt Request
Mask Register (IMASK)
from the stack
[1]
[2]
[3]
[5]
[7]
[8]
[9]
[6]
[10]
[11]
ICU vector table
(Note 1)
(Note 1)
Hardware preprocessing
when EIT is accepted
Hardware postprocessing
when RTE instruction
is executed
Read and overwrite
Interrupt Request Mask
Register (IMASK)
[4]
[12]
(Note 2)
(Note 2)
(Note 3)
(Note 4)
(Note 5)
(Note 4)
(Note 2)
Interrupt
handler
[1] to [12]: Processing of EI
by interrupt handler
To Next Page
Loading...
Need help?
General
