NEC uPD78P078Y Manuale Utente

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 regsters 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.

Describe the symbol reserved with assembler for the 1-bit manipulation instruction operand (sfr.bit).

This manipulation can also be specified with an address.

Describe the symbol reserved with assembler for the 8-bit manipulation instruction operand (sfr).

This manipulation can also be specified with an address.

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.

This column shows the addresses of the special function registers.

They have been defined as reserved words in the RA78K/0 and as the header file, sfrbit.h, in the CC78K/0.

They can be described as instruction operands when the RA78K/0, ID78K0-NS, ID78K0, and SM78K/0 are used.

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.

The register can be manipulated in bit units marked with a check (

√

) mark.

The register cannot be manipulated in bit units marked with “—”.

The register is set to the value immediately after the RESET signal is input.