Toshiba T2N - Manual (Page 158)

2. User Program Configuration
User's manual 145
2.3.3
Interrupt Program
There are a total of 5 types of interrupt program. These are 1 fixed-cycle
interrupt program which is executed cyclically with specified cycle time in
system information, and 4 I/O interrupt programs (#1 - #4) which are
started by interrupt signals from I/O modules with interrupt functions.
● Fixed cycle timer interrupt program
This is executed cyclically with a cycle which is registered in the
system information. The allowable setting is 5 to 1000ms (5ms
units). When no cycle is registered (blank), it is not executed.
● I/O interrupt programs (#1 - #4)
These are started by interrupt signals generated by I/O modules
with the corresponding interrupt functions. The coordination
between the interrupt program numbers and the I/O modules with
interrupt function is fixed as shown below.
For details of interrupt program operation, see Part 2 Section 3.3.
When automatic I/O allocation is executed in the state with interrupt I/O*
mounted, for coordination between the interrupt program munber and
the interrupt I/O, the lower number I/O interrupt programs are allocated
in sequence from the interrupt I/O closest to the CPU.
*) I/O modules with interrupt are under development
Each interrupt program must be ended by an IRET instruction.
NOTE