Z89175 Datasheet, PDF (30/68 Pages) Zilog, Inc. – Voice Processing Controllers

Z89175/Z89176
Voice Processing Controllers
Z8^® FUNCTIONAL DESCRIPTION
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:
s Power-On Reset
s Watch-Dog Timer
s Stop-Mode Recovery Source
s External Reset
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.
Zilog
65535
24575
Location of
First Byte of
Instruction
Executed
After RESET ₁₂
11
10
9
8
7
Interrupt
Vector
(Lower Byte)
6
5
4
Interrupt
Vector ₃
(Upper Byte)
2
1
0
External
ROM and RAM
On-Chip
ROM
In ROM Mode
IRQ5
IRQ5
IRQ4
IRQ4
IRQ3
IRQ3
IRQ2
IRQ2
IRQ1
IRQ1
IRQ0
IRQ0
Figure 17. Program Memory
30
PRELIMINARY
DS97TAD0100