Z8F0830HH020SG Datasheet, PDF (32/257 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore!^® F0830 Series
Product Specification
14
Address Space
The eZ8 CPU can access the following three distinct address spaces:
• The register file addresses access for the general purpose registers and the eZ8 CPU,
peripheral and general purpose I/O port control registers
• The program memory addresses access for all of the memory locations having execut-
able code and/or data
• The data memory addresses access for all of the memory locations containing only the
data
The following sections describe these three address spaces. For more information about
the eZ8 CPU and its address space, refer to the eZ8 CPU Core User Manual (UM0128),
which is available for download at www.zilog.com.
Register File
The register file address space in the Z8 Encore! MCU is 4 KB (4096 bytes). The register
file consists of two sections: control registers and general-purpose registers. When instruc-
tions are executed, registers defined as source are read and registers defined as destina-
tions are written. 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.
The upper 256 bytes of the 4 KB register file address space are reserved for controlling the
eZ8 CPU, on-chip peripherals and the I/O ports. These registers are located at addresses
from F00H to FFFH. Some of the addresses within the 256 B Control Register section are
reserved (unavailable). Reading from a reserved register file address returns an undefined
value. Writing to reserved register file addresses is not recommended and can produce
unpredictable results.
The on-chip RAM always begins at address 000H in the register file address space. The Z8
Encore! F0830 Series devices contain up to 256 B of on-chip RAM. Reading from register
file addresses outside the available RAM addresses (and not within the Control Register
address space), returns an undefined value. Writing to these register file addresses has no
effect.
PS025113-1212
Address Space