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CHAPTER 2 DEPENDENCE FUNCTIONS
2.2.5.4 Guarded Access Break
The guarded access break is an abortion of the program execution that happens when
the violation to the set access attribute, doing the access, and guarded (An undefined
area cannot be accessed) area are accessed.
■ Guarded Access Break
A guarded access break aborts a executing program when access is made in violation of the access attribute
set by using the [Setup] - [Memory Map] menu, and access is attempted to a guarded area (access-disabled
area in undefined area).
There are three types of the following in Guarded access break.
Code guarded
When the instruction execution is done to the area without the code attribute, the break is done.
Read guarded
When the area without the read attribute is read, the break is done.
Write guarded
When the area without the write attribute is write, the break is done.
If a guarded access occurs while executing a program, the following message is displayed on the Status Bar
and the program is aborted.
Break at Address by guarded access {code/read/write} at Access address
Note:
Code Guarded is affected by pre-fetching.
The F
2
MC-16L/16LX/16/16H family pre-fetch up to 4 bytes. So, when setting the program area
mapping, set a little larger area (5 bytes max.) than the program area actually used.
Similarly, the F
2
MC-16F family pre-fetch up to 8 bytes. So, when setting the program area mapping,
set a little larger area (9 bytes max.) than the program area actually used.