UPD784224 Datasheet, PDF (25/92 Pages) NEC – 16/8-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784224, 784225, 784224Y, 784225Y
6.2.3 Special function registers (SFRs)
The special function registers, such as the mode registers and control registers of the internal peripheral
hardware, are registers to which special functions are allocated. These registers are mapped to a 256-byte space
of addresses 0FF00H to 0FFFFH^Note.
Note On execution of the LOCATION 0H instruction. FFF00H to FFFFFH on execution of the LOCATION 0FH
instruction.
Caution
Do not access an address in this area to which no SFR is allocated. If such an address is accessed
by mistake, the µPD784225 may be in the deadlock status. This deadlock status can be cleared
only by inputting the RESET signal.
Table 6-1 lists the special function registers (SFRs). The meanings of the symbols in this table are as follows:
• Symbol ............................... Symbol indicating an SFR. This symbol is reserved for NEC’s assembler
(RA78K4). It can be used an sfr variable by the #pragma sfr directive with the
C compiler (CC78K4).
• R/W .................................... Indicates whether the SFR is read-only, write-only, or read/write.
R/W : Read/write
R : Read-only
W : Write-only
• Bit units for manipulation .. Bit units in which the value of the SFR can be manipulated.
SFRs that can be manipulated in 16-bit units can be described as the operand
sfrp of an instruction. To specify the address of this SFR, describe an even
address.
SFRs that can be manipulated in 1-bit units can be described as the operand of
a bit manipulation instruction.
• At reset .............................. Indicates the status of the register when the RESET signal has been input.
Data Sheet U12376EJ1V0DS00
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