Hitachi AP1 Data Book page 351

---------------------------------------------------------------------------HMCS404CL
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
Fig. 7 Interrupt Servicing Sequence
Instruction
Execution at
starting address
of the interrupt
routine
• 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 I nterrupt Enable/Disable
o
Disable
Enable
• External Interrupt (INTo, INTI)
To use external interrupt, select R32 /INT o , R33 /INT I port
for INTo, INT I mode by setting the Port Mode Register (PMR:
$004).
The External Interrupt Request Flags (lFO, IF!) are set at
the falling edge of INT
0,
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 INTI as TIMER-B external event, an External Interrupt
Mask (1M!) has to be set so that the interrupt request by INTI
will not be accepted.
• External Interrupt Request Flag
(I
FO: $000,2, I F1: $001,0)
The External Interrupt Request Flags (lFO, IFl) are set at
the falling edges of INT
0,
INT
1
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
349
Table 5. External I nterrupt 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 I pin,
~
1
lSI pin and
~2
ISO pin as shown in Table 6. The Port Mode Register will
be initialized to $0 by MCV reset, so that all these pins are set
to a port mode.
Table 6. Port Mode Register
PMR
R33/INTI pin
bit 3
0
Used as R33 port input/output pin
Used as INT 1 input pin
PMR
R32/INTo pin
bit 2
0 Used as R32 port input/output pin
Used as INTo input pin
PMR
R 41 /SI pin
bit 1
0
Used as R41 port input/output pin
Used as 51 input pin
PMR
bit 0
R42/S0 pin
0 Used as R42 port input/output pin
Used as SO output pin