Z8F0113HJ005EG Datasheet, PDF (28/245 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F0823 Series
Product Specification
13
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 general-purpose 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 contain data only
These three address spaces are covered briefly in the following subsections. For more
detailed information regarding the eZ8 CPU and its address space, refer to the eZ8 CPU
Core User Manual (UM0128), available for download at www.zilog.com.
Register File
The Register File address space in the Z8 Encore! XP^™ MCU is 4 KB (4096 bytes). The
Register File is composed of two sections: control registers and general-purpose registers.
When instructions are executed, registers defined as sources are read, and registers defined
as destinations 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 control of the
eZ8 CPU, the 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. Z8
Encore! XP F0823 Series devices contain 256 B–1 KB 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
produces no effect.
Program Memory
The eZ8 CPU supports 64 KB of Program Memory address space. F0823 Series devices
contain 1 KB to 8 KB of on-chip Flash memory in the Program Memory address space.
Reading from Program Memory addresses outside the available Flash memory addresses
PS024315-1011
PRELIMINARY
Address Space