Z86L0408PSC ZILOG [Zilog, Inc.], Z86L0408PSC Datasheet - Page 15

• Manufacturer Part Number: Z86L0408PSC
• Description: Z8 8-Bit Cost-Effective Microcontrollers
• Manufacturer: ZILOG [Zilog, Inc.]

Zilog
Program Memory. The Z8 addresses up to 1024,2048
bytes of internal program memory (Figure 11). The first 12
bytes of program memory are reserved for the interrupt
vectors. These locations contain six 16-bit vectors that cor-
respond to the six available interrupts. Bytes
0-1023/0-2047 are on-chip mask programmable ROM.
Register File. The Register File consists of three I/O port
registers, 61 general-purpose registers, and 12 control
and status registers R0-R3, R4-R127 and R241-R255, re-
spectively (Figure 12). General-purpose registers occupy
the 04H to 7FH address space. I/O ports are mapped as
per the existing CMOS Z8. The instructions can access
registers directly or indirectly through an 8-bit address
field. This allows short 4-bit register addressing using the
Register Pointer. In the 4-bit mode, the register file is divid-
ed into eight working register groups, each occupying 16
continuous locations. The Register Pointer (Figure 13) ad-
dresses the starting location of the active working-register
group.
DS97LVO0901
After RESET
(Lower Byte)
(Upper Byte)
First Byte of
Location of
Instruction
Executed
Interrupt
Interrupt
Vector
Vector
1024/2047
Figure 11. Program Memory Map
12
11
10
9
8
7
6
5
4
3
2
1
0
On-Chip
IRQ5
IRQ5
IRQ4
IRQ4
IRQ3
IRQ3
IRQ2
IRQ2
IRQ1
IRQ1
IRQ0
IRQ0
ROM
P R E L I M I N A R Y
Location
255
254
253
252
251
250
249
248
247
246
245
244
243
242
241
240
128
127
4
3
2
1
0
Z8 8-Bit Cost-Effective Microcontrollers
Figure 12. Register File
Interrupt Request Register
Interrupt Priority Register
General Purpose GPR
Stack Pointer (Bits 7-0)
Interrupt Mask Register
Program Control Flags
Not Implemented
General Purpose
Register Pointer
Timer/Counter0
Timer/Counter1
Ports 0-1 Mode
T o Prescaler
T1 Prescaler
Port 3 Mode
Port 2 Mode
Timer Mode
Registers
Reserved
Port 3
Port 2
Port 0
Z86L04/L08
Indentifiers
SPL
RP
Flags
IMR
IRQ
IPR
P01M
P3M
P2M
PRE0
T0
PRE1
T1
TMR
P3
P2
P1
P0
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