-------------------------------------------------------------HD614P080S
Instruction
Cycles
Instruction
execution
Interrupt
accepted
2
Stacking,
Reset
of
lIE
3
Stacking,
Vector
address
is
generated
4
5
JMPL
instruction
execution
on
the
vector address
6
Instruction
Execution
at
starting address
of
the
interrupt
routine
Fig. 7
Interrupt
Servicing Sequence
•
Interrupt
Enable Flag (lIE:
$000,0)
The Interrupt Enable Flag controls enable/disable
of
all inter-
rupt requests
as
shown
in
Table 3. The Interrupt Enable Flag
is
reset by the interrupt servicing and set by RTNI instruction.
Table 3.
Interrupt
Enable Flag
Interrupt
Enable Flag
Interrupt
Enable/Disable
o Disable
Enable
• External
Interrupt
(lN~,INTd
To use external interrupt, select R32/INTo, R33/INTI port
for INTo, INTI mode by setting the Port Mode Register (PMR:
$004).
The External Interrupt Request Flags (IFO, IF
l)
are set
at
the falling edge
of
INTo, INT I inputs.
INT I input can be used
as
a clock signal input
of
TIMER-B.
Then, TIMER-B counts up at each falling edge
of
input. When
using INT I
as
TIMER-B external event, an External Interrupt
Mask
(IMl)
has to
be
set
so
that the interrupt request
by
INTI
will
not
be
accepted.
• External
Interrupt
Request
Flag (lFO:
$000,2,
IF1:
$001,0)
The External Interrupt Request Flags (IFO, IF
l)
are set at
the
falling edges
of
INT 0-, INT I inputs respectively.
• External
Interrupt
Mask (lMO:
$000,3,
IM1:
$001,1)
The External Interrupt
Mask
is
used to mask the external
interrupt requests.
Table 4. External
Interrupt
Request Flag
External
Interrupt
Request Flags
Interrupt
Requests
o No
Yes
Table 5. External
Interrupt
Mask
External
Interrupt
Masks
I
nterrupt
Requests
o Enable
Disable
(masks)
•
Port
Mode Register (PMR:
$004)
The Port Mode Register
is
a 4-bit write-only register which
controls the
R32
/INT 0 pin,
R33
/INT 1 pin,
R41
lSI pin and
~2
ISO pin
as
shown in Table 6. The Port Mode Register will
be initialized
to
$0 by
MeV
reset,
so
that
all
these pins are set
to a port mode.
Table 6.
Port
Mode Register
PMR
R33/INT I pin
bit
3
0
Used as
R33
port
input/output
pin
Used as
I NT I
input
pin
PMR
R32/INTo pin
bit
2
0
Used as
R32
port
input/output
pin
Used as INTo
input
pin
PMR
R
4
dSI
pin
bit
1
0
Used as
R41
port
input/output
pin
Used
as
SI
input pin
PMR
R42/S0 pin
bit
0
0
Used as
R42
port
input/output
pin
Used as
SO
output
pin
271
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