ZiLOG Z8 Technical Manual

1.J MICROCOMPUTERS (Z8601/Z8611)
The Z8 can be a stand-alone microcomputer with
either 2K bytes (ZB601) or 4K bytes (Z8611) of
internal ROM, a traditional microprocessor that
can manage up to 124K bytes (ZB601) or 120K bytes
(ZB611) of external memory, Or a parallel proces-
sing element in a system with other processors and
peripheral controllers linked by a Z-BUS. In all
configurations, a large number of device pins are
available for I/O. Key features of the Z8601/11
microcomputer include:
• ROM 2K-byte (Z8601) or 4K-byte (Z8611) Program
Memory. This ROM is mask-programmed during
production with user-provided programs.
•
•
•
144-byte RAM Register File. The internal
register organization of the ZB microcomputer
centers around a 144-byte file composed of 124
general-purpose registers, 16 status and
control registers, and 4 I/O port registers.
Either an B-bit or a 4-bit address mode can be
used to access the register file. When the
4-bit mode is used, the register file is
divided into 9 groups of 16 working registers
each. A Register Pointer uses short-format
instructions to quickly access anyone of the
nine groups. Use of the 4-bit addressing mode
decreases access time and improves throughput.
Programmable Counter/Timers. Two 8-bit coun-
ter/timer circuits are provided, each driven by
its own prescaler. Both the counter/timers and
their prescaler circuits are programmable.
UART (Universal Asynchronous Receiver Transmit-
ter). A full-duplex UART is provided to
control serial data communications. One of the
on-chip counter/timer circuits provides the
required bit rate input to enable the UART to
operate at a maximum data transfer rate of
93.75K bits per second at a crystal frequency
of 12 MHz.
• I/O Lines/Ports. The ZB microcomputer provides
32 input/output lines, arranged as 4 8-bit
ports. Under software control, the I/O ports
(Ports 0, 1, 2, 3) can be programmed as input,
output, or additional address lines. The I/O
ports can also be programmed to provide timing,
status signals, interrupt inputs and serial or
parallel I/O (with or without handshake).
I-V I UIII.&.., \J",,",,~ y ..... ., ..
• Vectored Interrupts. The ZB MPU permits the
use of six di fferent interrupts from any of
eight different sources. Four Port 3 lines
(P3
0
-P3
3
), serial input pin (P3
0
), the serial
output pin (P3
7
) and both counter/timer
circuits may be interrupt sources. All
interrupts are vectored and are both maskable
and
prioritized.
• Oscillator Circuit. An oscillator circuit that
can be driven from an external clock or crystal
is provided on the Z8 microcomputer. The
oscillator will accept an input frequency of up
to 12 MHz on the two input pins provided.
• Optional Power-Down Feature.
This option
permits normal input power to be removed from
the chip without affecting the contents of the
register file. The power-down funct ion
requires an external battery backup system.
Pin functions and descriptions for the ZB601/11
microcomputer can be found in Chapter 6.
1.4 DEVELOPMENT DEVICE (Z8612)
A development device allows users to prototype a
system with an
actual hardware device and to
develop the code that is eventually mask-pro-
grammed into the on-chip ROM of the Z8601 or Z8611
microcomputer. Development devices are also use-
ful in applications where production volume does
not justify the expense of a ROM system. The
ZB612 development device is identical to its
equivalent microcomputer, the Z8611, with the fol-
lowing exceptions:
• No internal ROM is provided, so that code is
developed in an off-chip memory.
• The normally internal ROM address and data
lines are buffered and brought out to external
pins to interface with the external memory.
• Control lines are added to interface with
external program memory.
• The device package is enlarged in order to
accommodate the new control, address, and data
lines.
Pin functions and descriptions for the development
device can be found in the Appendix.
1-J

ZiLOG Z8 Specifications

General

Brand	ZiLOG
Model	Z8
Category	Desktop
Language	English