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Flags ER: Indirectly addressed DM word is non-existent. (Content of :DM word is
not BCD, or the DM area boundary has been exceeded.)
C, and/or N are not within specified values.
Example 1: Input Interrupt This example shows how to unmask a particular interrupt input. Input interrupt
subroutines will be executed when the CPU receives the corresponding inter-
rupt input, regardless of the location in the CPU’s cycle. These interrupts are
useful when using program sections of uncertain length, such as event pro-
grams.
All input interrupts are masked at the start of operation, and the desired interrupt
input is unmasked using INT(89) with N=000 and C=000. As shown in the follow-
ing diagram, the subroutine would be executed if there were an input from input
interrupt 00 when that interrupt input was unmasked.
LD 25315
INT(89) 000
000
#00FE
SBN(92) 00
RET(93)
END(01)
Main program
Subroutine
Main program
Interrupt from
interrupt input 00
Only interrupt input
00 is unmasked.
First Cycle Flag
Note Depending on the setting of DM 6621 in the PC Setup, Host Link servicing, Re-
mote I/O servicing, Special I/O Unit servicing, and individual instruction execu-
tion will be completed before the subroutine is executed. Refer to page 255 for
details.
This example shows how to set the interval between scheduled interrupts.
Scheduled interrupt subroutines will be executed at fixed intervals, regardless of
the location in the CPU’s cycle. This interrupt is useful for program sections such
as regular monitoring programs.
Example 2: Scheduled
Interrupt
Subroutines and Interrupt Control Section 5-23