PD17012_15 Datasheet, PDF (45/320 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLERS WITH DIGITAL TUNING SYSTEM HARDWARE

µPD17012, 17P012
5.4 Window Register (WR)
5.4.1 Configuration of window register
Figure 5-4 shows the configuration of the window register.
As shown in the figure, the window register consists of 4 bits at address 78H of the system register.
Figure 5-4. Configuration of Window Register
Address
Name
Symbol
Bit
Data
78H
Window register
(WR)
WR
b3 b2 b1 b0
M
L
S
S
B
B
Power-on
Clock stop
CE
Undefined
Holds previous
status
5.4.2 Function of window register
The window register is used to transfer data with the register file (RF) which is explained later.
To transfer data between the window register and register file, the dedicated instructions “PEEK WR, rf” and
“POKE rf, WR” are used (rf: address of register file).
The following paragraphs (1) and (2) explain the operations to be performed when each of these instructions
is executed.
Also refer to 8. REGISTER FILE (RF).
(1) “PEEK WR, rf” instruction
When this instruction is executed, the contents of the register file addressed by “rf” are transferred to
the window register.
(2) “POKE rf, WR” instruction
When this instruction is executed, the contents of the window register are transferred to the register file
addressed by “rf”.
Data Sheet U10101EJ4V0DS
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