Zilog Z8F0130 - Manual (Page 38)

eZ8
™
CPU Core
User Manual
UM012820-0810 Address Space
23
Register File Precautions
Some control registers within the Register File provide Read-Only or
Write-Only access. When accessing these Read-Only or Write-Only
registers, insure that the instructions do not attempt to read from a Write-
Only register or, conversely, write to a Read-Only register. To determine
which control registers allow either Read-Only or Write-Only access,
refer to the Zilog Product Specification specific to your Z8 Encore!
device.
Program Memory
The eZ8 CPU can access 64 KB (65,536 bytes) of Program Memory. The
Program Memory provides storage for both executable program code and
data. For each product within the eZ8 CPU family, a block of Program
Memory beginning at address
0000h is reserved for option bits, Reset
vector, Watchdog Timer time-out vector, Illegal Instruction Trap vector,
and the Interrupt vectors. The rest of the Program Memory stores code
and data. Program Memory is accessed using Op Code fetches, operand
fetches, and LDC/LDCI instructions.
Table 7 provides an example of a
Program Memory map for a eZ8 CPU product with 64 KB of Program
Memory and 16 interrupt vectors.
Table 7. Program Memory Map Example
Program Memory

Address (Hex) Description
0000–0001 Option bits.
0002–0003 Reset vector.
0004–0005 Watchdog Timer vector.
0006–0007 Illegal Instruction Trap vector.