Zilog Z8F0130 Manual do Utilizador descarregar pdf (Página 32)

eZ8

™

CPU Core

User Manual

UM012820-0810 Address Space

Address Space

The eZ8

™

CPU can access three distinct address spaces:

•

The Register File contains addresses for the general-purpose registers

and the eZ8 CPU, peripheral, and I/O port control registers.

•

The Program Memory contains addresses for all memory locations

having executable code and/or data.

•

The Data Memory contains addresses for all memory locations that

hold data only.

The eZ8 CPU supports a maximum of 4096 consecutive bytes (registers)

in the Register File. The Register File is composed of two sections:

1. Control Registers

2. General-Purpose Registers

The upper 256 bytes are reserved for control of the eZ8 CPU, the on-chip

peripherals, and the I/O ports. These 256 registers are always located at

addresses from

F00h to FFFh.

When instructions execute, registers are read from when defined as

sources and written to when defined as destinations. The architecture of

the eZ8 CPU allows all general-purpose registers to function as

accumulators, address pointers, index registers, stack areas, or scratch pad

memory.

Some eZ8 CPU products contain a register file that is less than the

maximum of 4096 bytes. For eZ8 CPU products with less than 4096B in

the Register File, reading from an unavailable Register File addresses

returns an undefined value. Writing to an unavailable Register File

addresses produces no effect. Refer to the Zilog Product Specification

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