UPD784031 Datasheet, PDF (22/90 Pages) NEC – 16/8-BIT SINGLE-CHIP MICROCONTROLLER

µPD784031
7.2.3 Special function registers (SFRs)
The special function registers are registers with special functions such as mode registers and control registers
for built-in peripheral hardware. The special function registers are mapped onto the 256-byte space between 0FF00H
and 0FFFFH^Note.
Note Applicable when the LOCATION 0 instruction is executed. FFF00H-FFFFFH when the LOCATION 0FH
instruction is executed.
Caution Never attempt to access addresses in this area where no SFR is allocated. Otherwise, the
µPD784031 may be placed in the deadlock state. The deadlock state can be cleared only by a
reset.
Table 7-1 lists the special function registers (SFRs). The titles of the table columns are explained below.
• Abbreviation ................... Symbol used to represent a built-in SFR. The abbreviations listed in the table are
reserved words for the NEC assembler (RA78K4). The C compiler (CC78K4) allows
the abbreviations to be used as sfr variables with the #pragma sfr command.
• R/W ................................. Indicates whether each SFR allows read and/or write operations.
R/W : Allows both read and write operations.
R : Allows read operations only.
W : Allows write operations only.
• Manipulatable bits .......... Indicates the maximum number of bits that can be manipulated whenever an SFR is
manipulated. An SFR that supports 16-bit manipulation can be described in the sfrp
operand. For address specification, an even-numbered address must be speci-
fied.
An SFR that supports 1-bit manipulation can be described in a bit manipulation
instruction.
• When reset ..................... Indicates the state of each register when RESET is applied.
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