ZiLOG Z8 Technical Manual

7.1 INTRODUCTION
The ROM less versions of the ZB microcomputer have
40 external pins, of which 24 are programmable I/O
pins. Of the remaining 16 pins, 8 form an
Address/Data bus and the others are used for power
and control. Up to 8 I/O pins can be programmed
as additional address lines to be used for
external memory interface.
7.2 PIN DESCRIPTIONS
AS. Address Strobe (output, active low, pin 9).
Address Strobe is pulsed Low once at the beginning
of each machine cycle. The rising edge of AS
indicates that addresses, Read/Write (R/W), and
Data Memory (OM) signals are valid when output for
program or data memory transfers.
iiEffi
+5V
R/W GND
os
XTAL1
AS XTAL2
POO
P20
PO,
P2,
P0
2
P2
2
PORTO PORT 2
(NIBBLE
P0
3
P2
3
(BIT PRO·
PROGRAMMABLE)
P0
4
P2
4
GRAMMABLE)
1/0 OR As-A'5
1/0
PO
S
Z8681182 P2s
POa
MCU P2
a
P0
7
P2
7
P1
0
P3
0
P1,
P3,
P1
2
P3
2
PORT 3
(FOUR INPUT;
Chapter 7
External Interface
(Z8681, Z8682)
Os. Data Strobe (output, active low, pin 8).
Data Strobe provides the timing for data movement
to or from Port 1 for each memory transfer.
During a Write cycle, data out is valid at the
leading edge of 55. During a Read cycle, data in
must be valid prior to the trailing edge of 55.
R/i. Read/Write. (output, pin 7). Read/Write
determines the direction of data transfer for
memory transactions. R/W is Low when writing to
program or data memory, and High for all other
transactions.
P01-P07. Address/Data Port (inputs/outputs, TTl-
compatible, pins 13-20). Port 1 is permanently
configured as a multiplexed Address/Data memory
interface. The lower eight address lines (AO-A7)
are multiplexed with data (00-07).
+5V
P3
s
XTAL2
2
39 P3,
XTAL1 3
38
P2
7
P3
7
4
37 P2
s
P3
0
P2
S
RESET
6
35 P2
4
R/W
7 34
P2
3
DS
8 33 P2
2
AS 32
P2,
P3
s
10
Z8681182
31
P2
0
GND
11
MCU
30
P3
3
P3
2
12
29
P3
4
POo
13
28
P1
7
PO,
14
27
P1
s
P0
2
15
26
P1
s
PORT 1
P1
3
P3
3
FOUR OUTPUT)
P0
3
16
25
P1
4
ADo-AD7
P1
4
P3
4
SERIAL AND
PARALLEL
1/0
P0
4
17
24
P1
3
P1
s
P3
s
AND
CONTROL
PO
s
18 23
P1
2
P1
a
P3
a
PO
s
19
22 P1,
P1
7
P3
7
P0
7
20
21
P1
0
Figure 7-1.
Z8681/82 Pin Functions
Figure 7-2.
Z86B1/82 Pin Assignments
3047·052,2037-002
7-1

ZiLOG Z8 Specifications

General

Brand	ZiLOG
Model	Z8
Category	Desktop
Language	English