Fujitsu FR81S User Manual
CHAPTER 3: CPU
8. Programming Model
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : CPU
FUJITSU SEMICONDUCTOR CONFIDENTIAL
18
8.2. System Register
The system register is shown below.
System register is an address mapping register for controlling system. These registers can be accessed only
in the privilege mode. There are system registers as follows.
⋅
Clock control-related register
⋅
Reset control-related register
⋅
Debug control-related register
⋅
Memory protection-related register
⋅
DMA-related register
⋅
Watchdog timer register
⋅
Wildregister control register
⋅
FLASH control register
When these registers are written and/or read in the user mode, the illegal instruction exception (data access
error) occurs.
The access protection to system registers is judged on a priority bases than the memory protection function.
Therefore, when user access to the system register area is enabled in the memory protection function and
access is disabled in the privilege mode, those settings are disabled. Read and/or write is enabled only in the
privilege mode and read and/or write is disabled in the user mode.
MB91520 Series
MN705-00010-1v0-E
115