Z89175 Zilog., Z89175 Datasheet - Page 30

• Manufacturer Part Number: Z89175
• Description: Voice Processing Controllers
• Manufacturer: Zilog.

Z89175/Z89176
Voice Processing Controllers
Z8
The Z8 core of the Z89175/176 incorporates special func-
tions to enhance the Z8’s application in a variety of voice-
processing applications.
Reset. The device is reset in one of the following condi-
tions:
Program Memory. The Z8 addresses up to 24 KB of inter-
nal program memory and 40 KB external memory (Figure
17). The first 12 bytes of program memory are reserved for
the interrupt vectors. These locations contain six 16-bit
vectors which correspond to the five user interrupts and
one DSP interrupt. Byte 12 to byte 24575 consist of on-
chip mask-programmed ROM. At addresses 24576 and
greater the Z8 executes external program memory. In
ROMless mode, the Z8 will execute external program
memory beginning at byte 12 and continuing through byte
65535.
30
®
Power-On Reset
Watch-Dog Timer
Stop-Mode Recovery Source
External Reset
FUNCTIONAL DESCRIPTION
P R E L I M I N A R Y
(Lower Byte)
(Upper Byte)
After RESET
First Byte of
Location of
Instruction
Executed
Interrupt
Interrupt
Vector
Vector
65535
24575
Figure 17. Program Memory
12
11
10
9
8
7
6
5
4
3
2
1
0
ROM and RAM
In ROM Mode
On-Chip
External
ROM
IRQ5
IRQ5
IRQ4
IRQ4
IRQ3
IRQ3
IRQ2
IRQ2
IRQ1
IRQ1
IRQ0
IRQ0
DS97TAD0100
Zilog