63
μPD780948, μPD78F0948, μPD780949, μPD78F0949
3.2.3 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 registers can be manipulated in a similar way as the general registers, by using
operation, transfer, or bit-manipulate instructions. The special function registers are read from and written
to in specified manipulation bit units (1, 8, and/or 16) depending on the 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 3-3 gives a list of special function registers. The meaning of items in the table is as follows.
Symbol
The assembler software RA78K0 translates these symbols into corresponding addresses where the
special function registers are allocated. These symbols should be used as instruction operands in
the case of programming.
R/W
This column shows whether the corresponding special function register can be read or written.
R/W
: Both reading and writing are enabled.
R
: The value in the register can read out. A write to this register is ignored.
W
: A value can be written to the register. Reading values from the register is impossible.
Manipulation
The register can be manipulated in bit units.
After reset
The register is set to the value immediately after the RESET signal is input.