D17133CS datasheet(87/289 Pages) NEC

87 / 289 page

CHAPTER 9

Figure 9-2. Relationship Between the Register File and Data Memory

Data memory

Column address

123456789 A B C D E F

BANK0

System register

Control register

Port register

9.2 FUNCTIONS OF THE REGISTER FILE

9.2.1 Functions of the Register File

The register file is mainly used as a control register (a register called the control register is allocated in the register

file) for specifying conditions for peripheral hardware.

This control register is allocated within the register file at address location 00H to 3FH.

The rest of the register file (40H to 7FH) overlaps with data memory. As shown in 9.2.3, because of this overlap,

this area of the register file is the same as normal memory with one exception: The register file manipulation

instructions PEEK and POKE can be used with this area of memory but not with normal data memory.

9.2.2 Control Register Functions

The peripheral hardware whose conditions can be controlled by control registers is listed below.

For details concerning peripheral hardware and the control register, refer to the section for the peripheral hardware

concerned.

• Stack

• INT pin

• Power-on/power-down reset

• Comparator

• Timer

• General ports

• Serial interface

• Interrupts

D17133CS Arkusz danych(PDF) 87 Page - NEC