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3.9 SPECIAL FUNCTION REGISTERS (SFRS)
These are registers to which a special function is assigned, such as on-chip peripheral hardware mode registers, control
registers, etc. They are mapped onto the 256-byte space from 0FF00H to 0FFFFH
Note
When the LOCATION 0H instruction is executed. When the LOCATION 0FH instruction is executed, the area is
FFF00H to FFFFFH.
Caution Addresses onto which SFRs are not assigned should not be accessed in this area. If such an address is
as accessed by mistake, the µ PD784038 may become deadlocked. A deadlock can only be released by
reset input.
A list of special function registers (SFRs) is given in Table 3-5. The meaning of the items in the table is as explained below.
• Symbol ............................... Symbol that indicates the incorporated SFR. This is a reserved word in the NEC Electronics
• R/W .................................... Indicates whether the corresponding SFR is read/write enabled.
• Manipulable Bit Units ......... Indicates the applicable manipulation bit units when the corresponding SFR is manipulated.
• After Reset ......................... Indicates the status of the register after RESET input.
CHAPTER 3 CPU ARCHITECTURE
assembler (RA78K4). With the C compiler (CC78K4), this symbol can be used as an sfr
variable by means of a #pragma sfr command.
R/W: Read/write enabled
R
: Read-only
W
: Write-only
A 16-bit-manipulable SFR can be written in the operand "sfrp", and when specified by an
address, an even address is specified.
A bit-manipulable SFR can be written in a bit manipulation instruction.
User's Manual U11316EJ4V1UD
Note
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