PD17012_15 Datasheet, PDF (64/320 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLERS WITH DIGITAL TUNING SYSTEM HARDWARE

µPD17012, 17P012
8.3 Register File Manipulation Instructions (“PEEK WR, rf” and “POKE rf, WR”)
Data is read from or written to the register file via the window register in the system register by using a register
file manipulation instruction (“PEEK WR, rf” or “POKE rf, WR”). The operation of each instruction is explained
below.
(1) “PEEK WR, rf”
This instruction reads the data of the register file addressed by “rf” to the window register.
(2) “POKE rf, WR”
This instruction writes the data of the window register to the register file addressed by “rf”.
8.4 Control Registers
Figure 8-3 shows the configuration of the control registers.
As shown in this figure, a total of 64 nibbles (64 words × 4 bits) at addresses 00H to 3FH of the register file
can be used as control registers.
Of these nibbles, however, 33 nibbles are actually used. The remaining 31 nibbles are unused registers that
are prohibited from being read or written.
Each control register has an attribute of 1 nibble, and is classified into four types: read/write (R/W), read-
only (R), write-only (W), and read-and-reset (R & Reset).
Nothing is changed even if data is written to a read-only (R and R & Reset) register.
An undefined value is read if a write-only (W) register is read.
Of the 4-bit data in 1 nibble, the bit fixed to 0 is always 0 when it is read or written.
The 31 nibbles of unused registers are undefined when they are read, and nothing is changed when data is
written to them.
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Data Sheet U10101EJ4V0DS