PD17225_15 Datasheet, PDF (25/86 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLER FOR SMALL GENERAL-PURPOSE INFRARED REMOTE CONTROL TRANSMITTER

µPD17225, 17226, 17227, 17228
2.5.2 Control registers
The control registers consists of a total of 64 nibbles (64 x 4 bits) of the addresses 00H-3FH of the register file.
Of these, however, only 14 nibbles are actually used. The remaining 50 nibbles are unused registers that are inhibited
from being read or written.
When the “PEEK WR, rf” instruction is executed, the contents of the register file addressed by “rf” are read to the window
register.
When the “POKE rf, WR” instruction is executed, the contents of the window register are written to the register file
addressed by “rf”.
When using the assembler (RA17K), the macro instructions listed below, which are embedded as flag type symbol
manipulation instructions, can be used. The macro instructions allow the contents of the register file to be manipulated
in bit units.
For the configuration of the control register, refer to Figure 11-1 Register File List.
SETn
: Sets flag to “1”
CLRn
: Sets flag to “0”
SKTn
: Skips if all flags are “1”
SKFn
: Skips if all flags are “0”
NOTn
: Complements flag
INITFLG : Initializes flag
INITFLGX : Initalizes flag
2.5.3 Notes on using register files
When using the register files, bear in mind the points described below. For details, refer to µPD172xx subseries
User’s Manual (U12795E).
(1) When manipulating control registers (read-only and unused registers)
When manipulating the write-only (W), the read-only (R) and unused control registers by using the assembler
or in-circuit emulator, keep in mind the following points:
• When device operates
Nothing changes even if data is written to the read-only register.
If the unused register is read, an undefined value is read; nothing is changed even if data is written to this
register.
• Using assembler
An error occurs if instruction is excecuted to read data to the write-only register.
An error occurs if an instruction is executed to write data to the read-only register.
An error also occurs if an instruction is executed to read or write the unused address.
• When an in-circuit emulator (IE-17K or IE-17K-ET) is used (when instruction is executed for patch
processing)
An undefined value is read if the write-only register is read, and an error does not occur.
Nothing changes even if data is written to the read-only register, and an error does not occur.
An undefined value is read if the unused address is read; nothing changes even if data is written to this
address. An error does not occur.
Data Sheet U12643EJ2V0DS00
23