R01UH0823EJ0100 Rev.1.00
Page 334 of 1823
Jul 31, 2019
RX23W Group
17. Memory-Protection Unit (MPU)
17.3.4
Flow for Determination of Access by the Memory-Protection Function
shows the flow of determination in the case of data access and
shows the flow of determination
in the case of instruction access.
Figure 17.2
Flow of Determination for Data Access
Data access by the CPU
No
Yes
Access permitted
No
Permit data access
Generate a data memory-
protection error
Permit data access
Generate a data memory-
protection error
Access permitted
Yes
Processor mode?
Supervisor mode
Permit data access
User mode
Yes
No
Generate a data memory-
protection error
Note 1. Permission takes priority when the settings lead to overlapping regions overlap and are different for the given regions
(this includes the background region).
Permit data access
Is access to an
MPU-related register?
Is memory protection
enabled?
Is access to an access-
control region?
Access prohibited
Access prohibited
(default)
Determination in accord with
the access-control information for
the given region*
1
Determination in accord with
the access-control information for
the background region