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114 T1/T1S User’s Manual
6. Programming Information

6.6.4 I/O interrupt programs

The I/O interrupt program is also the highest priority task. It is executed immediately
when the interrupt factor is generated, with suspending ot her operation.
the following 4 types I/O interrupt programs are supported in the T1/T1S.
(1) I/O interrupt #1
The I/O interrupt #1 is used with the high speed counter function. When the count
value reaches the preset value, etc., the I/O interrupt #1 is activated immediately
with suspendi ng other operation. The end of the I/O interrupt #1 is recognized by the
IRET instruction. For det ailed informat ion, r efer to sect ion 8.3.
(2) I/O interrupt #2
The I/O interrupt #2 is also used with the high speed counter function. Refer to
section 8.3 for details.
(3) I/O interrupt #3
The I/O interrupt #3 is used with the interrupt input function. When the state of the
interrupt input is changed from OFF to ON (or ON to OFF), the I/O interrupt #3 is
activated immediately with suspending other operation. The end of the I/O interrupt
#3 is also recognized by the IRET instruction. For det ailed informat ion, r efer to
section 8.4.
(4) I/O interrupt #4
The I/O interrupt #4 is also used with the interrupt input function. Refer to section 8.4
for details.
If an interrupt factor is generated while other interrupt program is executing (including the
timer interrupt), the inte r r upt fact or is held. Then it will be activated after finishing t he
other inter rupt program execution.
If two or more interrupt factors are generated at the same time, the priority is as follows.
Timer > I/O #1 > I/O #2 > I/O #3 > I/O #4
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