ZiLOG Z8 Technical Manual

Address Spaces
6
Location 01
!lrst byte 01
Instruction
executed
alter reset
Interrupt
Vector
(Lower Byte)
Interrupt
Vector
(Upper Byte)
5535
4096
4095
~
11
10
9
8
7
6
5
4
3
2
0
EXTERNAL
ROM OR RAM
ON·CHIP
ROM
~------------
IR05
IR05
IR04
IR04
IR03
IR03
"
IR02
~
IR02
IR01
IR01
IROO
IROO
Figure 3-5b. Z8611 Program Memory Map
6
Location 01
lirst byte 01
Instruction
executed
alter reset
Interrupt
Vector
(Lower Byte)
Interrupt
Vector
(Upper Byte)
5535
EXTERNAL
ROM OR RAM
~
~------------
11
IR05
10
IR05
9
IR04
8 IR04
7 IR03
6
IR03
5"
IR02
4~
IR02
3
IR01
2
IR01
IROO
0
IROO
Figure 3-5c. Z8681 Program Memory Map
LOCATION OF
FIRST BYTE OF
INSTRUCTION
EXECUTED
AFTER RESET
65535
~
2066
2065
2056
2055
2054
2053
2052
2051
2050
2049
2048
2047
EXTERNAL
ROM OR RAM
~----------
IR05
IR05
JP
IR04
IR04
JP
IR03
IR03
JP
IR02
IR02
JP
IR01
IR01
JP
IROO
IROO
JP
NOT
ADDRESSABLE
Figure 3-5d. Z8682 Program Memory Map
When an interrupt occurs, the address stored in
the interrupt I s vector location points to a ser-
vice routine. This routine assumes program con-
trol.
The first 2K bytes of program memory are not
addressable in the Z8682 ROMless version.
Beginning at address 2048 the first 18 bytes
contain interrupt vectors which are Jump Direct
instructions. When an interrupt occurs, the Z8682
executes the corresponding Jump to interrupt.
The first address available for a user program is
location 12. This address is loaded into the
Program Counter after a hardware reset.
The first address available for a user program in
the Z8682 is location 2066 (Hexadecimal ~o812).
This address is loaded into the Program Counter
after a hardware reset.
3-4 2038-004, 3047-073, 3047-035

ZiLOG Z8 Specifications

General

Brand	ZiLOG
Model	Z8
Category	Desktop
Language	English