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5.2.3 Special Function Register (SFR)
Unlike a general register, each special-function register has special functions.
It is allocated in the FF00H to FFFFH area.
The special-function register can be manipulated like the general register, with the operation, transfer and bit
manipulation instructions. Manipulatable bit units, 1, 8 and 16, depend on the special-function register type.
Each manipulation bit unit can be specified as follows.
• 1-bit manipulation
Describe the symbol reserved with assembler for the 1-bit manipulation instruction operand (sfr.bit).
This manipulation can also be specified with an address.
• 8-bit manipulation
Describe the symbol reserved with assembler for the 8-bit manipulation instruction operand (sfr).
This manipulation can also be specified with an address.
• 16-bit manipulation
Describe the symbol reserved with assembler for the 16-bit manipulation instruction operand (sfrp).
When addressing an address, describe an even address.
Table 5-3 gives a list of special-function registers. The meaning of items in the table is as follows.
• Symbol
Symbols indicating the addresses of special function register. These symbols are reserved words for the RA78K/
0 and defined by header file sfrbit.h for the CC78K/0, and can be used as the operands of instructions when
the RA78K/0, ID78K0-NS, ID78K0, and SM78K0 are used.
• R/W
Indicates whether the corresponding special-function register can be read or written.
R/W : Read/write enable
R
: Read only
W
: Write only
• Manipulatable bit units
indicates bit units (1, 8 or 16 bits) in which the register can be manipulated. — indicates that the register cannot
be manipulated in the indicated bit units.
• After reset
Indicates each register status upon RESET input.
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CHAPTER 5 CPU ARCHITECTURE
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