ZILOG Z8631804PEC, Z8631804PSC, Z8631804SEC, Z8631804SSC Datasheet

1

P

RELIMINARY

P

RODUCT

S

PECIFICATION

FEATURES

ROM

Device

Z86318 124 14 21 0V to 6.0V

Note: *General-Purpose

■

–40 ° C to +105 ° C Operating Temperature Range

■

Low-Power Consumption: 33 mW (Typical)

■

ROM Mask Options:
– Permanent Watch-Dog Timer

(KB)

RAM*

(Bytes)

I/O

Lines

Voltage

Range

GENERAL DESCRIPTION

The Z86318 is a member of the Z8
microcontrollers. This device offers on-board pull-up and
pull-down resistors (ROM mask-option programmable on a
nibble basis), a scalable trip-point buffer to accommodate
opto-transistor outputs, and high drive ports capable of up
to 20 mA current sinking per pin (3 pins maximum).

The Z86318 features I/O Ports (IOL = 20 mA at VOL =

0.8V, 3 pins max.) to provide increased current sinking ca­pabilities. These devices also offer users a selection of
ROM mask options, which include a permanently enabled
Watch-Dog Timer that ensures operational reliability
across a broad range of application environments.

For applications requiring powerful I/O capabilities, the
Z86318 provides dedicated input and output lines that are
grouped into three ports. These ports can be configured by
means of ROM mask options (nibble-programmable) as
pull ups, pull downs, or neither. There are two basic ad­dress spaces available. Program Memory, and 124 bytes
of general-purpose registers.

®

MCU family of CMOS

Z86318

®

Z8

MCU 8-B

– ROM Protect
– Low-Voltage Protection
– Pull-Up/Pull-Down I/O Pins

(Nibble Programmable)

– Feedback Resistor on the On-Chip Oscillator

■

On-Chip Oscillator (Crystal, Ceramic Resonator,
LC, or External Clock Drive)

■

Fast Instruction Pointer: 1.5 µ s @ 4 MHz

■

ESD Protection Circuitry

The Z86318 devices provide two on-chip 8-bit programma­ble counter/timers with a large number of user-selectable
modes. Each counter/timer is driven by its own 6-bit pro­grammable prescaler. The Z86318 counter/timers off-load
system real-time tasks such as counting/timing and in­put/output data communications for increased system effi­ciency.

Notes: All Signals with a preceding front slash, “/”, are ac-

tive Low, e.g.; B//W (WORD is active Low); /B/W (BYTE is
active Low, only).

Power connections follow conventional descriptions be­low:

Connection Circuit Device

Power VCC VDD

Ground GND VSS

IT

M

ICROCONTROLLER

1

DS96KEY0103 (8/96)

P R E L I M I N A R Y

1

2

Z86318

®

Z8

MCU 8-Bit Microcontroller

GENERAL DESCRIPTION (Continued)

Input

Port 3

Counter/

Timers (2)

Interrupt

Control

VSS XTALVDD

ALU

FLAG

Register

Pointer

Register File

144 x 8-Bit

Machine

Timing & Inst.

Control

Prg. Memory
3072 x 8-Bit (318)
2048 x 8-Bit (319)

Program

Counter

Port 2

I/O

(Bit Programmable)

Port 0

I/O

Figure 1. Z86318 Functional Block Diagram

P R E L I M I N A R Y

1

PIN DESCRIPTIONS

®

Z8

MCU 8-Bit Microcontroller

Z86318

P24
P25

P26
P27

VDD

XTAL2

XTAL1

P31
P32

1
2
3
4

Z86318

5
6
7
8
9

18
17
16

15
14
13
12

11
10

P23
P22
P21
P20

VSS
P02
P01
P00
P33

Figure 2. Z86318 18-Pin DIP/SOIC

Pin Configuration

ABSOLUTE MAXIMUM RATINGS

Sym. Parameter Min. Max. Units

V
T
T

Note:

*Voltages on all pins with respect to Ground.
†See Ordering Information.

Supply V oltage* –0.3 +7 V

DD

Storage Temp . –65 ° +150 °

STG

Oper. Ambient Temp. † † C

A

C

Table 1. Z86318 18 Pin DIP/SOIC Pin Identification

Pin # Symbol Function Direction

1-4 P24-P27 Port 2, Pins 4, 5, 6, 7 In/Output
5V

DD

Power Supply Input

6 XTAL2 XTAL Osc. Clock Output
7 XTAL1 XTAL Osc. Clock Input
8 P31 Port 3, Pin 1 Input
9 P32 Port 3, Pin 2 Input
10 P33 Port 3, Pin 3 Input
11-13 P00-P02 Port 0, Pins 0, 1, 2 In/Output
14 V

SS

Ground

15-18 P20-P23 Port 2, Pins 0, 1, 2, 3 In/Output

Stresses greater than those listed under Absolute Maxi­mum Ratings may cause permanent damage to the de­vice. This is a stress rating only; operation of the device at
any condition above those indicated in the operational sec­tions of these specifications is not implied. Exposure to ab­solute maximum rating conditions for extended periods
may affect device reliability.

P R E L I M I N A R Y

3

Z86318

®

Z8

MCU 8-Bit Microcontroller

STANDARD TEST CONDITIONS

4

The characteristics listed below apply for standard test
conditions as noted. All voltages are referenced to
Ground.Positive current flows into the referenced pin (Fig­ure 3).

CAPACITANCE

TA = GND = 0V, f = 1.0 MHz, unmeasured pins returned to Ground.

Parameter Min. Max.

Input Capacitance 0 10 pF
Output Capacitance 0 20 pF
I/O Capacitance 0 25 pF

V

SPECIFICATION

CC

From Output

Under Test

150 pFI

Figure 3. Test Load Diagram

V

= 4.0V to 6.0V

CC

P R E L I M I N A R Y

1

®

Z8

MCU 8-Bit Microcontroller

Z86318

DC ELECTRICAL CHARACTERISTICS

T

= 0 ° C to +70 ° C

A

Sym Parameter

V

DD

Min Max @ 25 ° C Units Conditions

Max Input Voltage 4.0V 12 V V

V

V

V

V

V

V

V

V

V

V

Clock Input High

CH

Voltage
Clock Input Low

CL

Voltage
Input High Voltage

IH

Schmitt-Triggered
Input High Voltage

IH

CMOS Input
Input Low Voltage

IL

Schmitt-Triggered
Input Low Voltage

IL

CMOS Input
Output High

OH

Voltage
Output Low Voltage 4.0V

OL1

Output Low Voltage 4.0V

OL2

VCC Low-Voltage

LV

4.0V

6.0V

4.0V

6.0V

4.0V

6.0V

4.0V

6.0V

4.0V

6.0V

4.0V

6.0V

4.0V

4.5V

6.0V

6.0V

0.7 V

0.7 V

V

SS

V

SS

0.7 V

0.7 V

0.7 V

0.7 V

V

SS

V

SS

V

SS

V

SS

V

DD

V

DD

DD
DD

– 0.3
– 0.3

DD
DD

DD
DD

– 0.3
– 0.3

– 0.3
– 0.3

– 0.4
– 0.4

V

DD

V

DD

0.2 V

0.2 V

V

DD

V

DD

V

DD

V

DD

0.2 V

0.2 V

0.2 V

0.2 V

+ 0.3
+ 0.3

DD
DD

+ 0.3
+ 0.3

+ 0.3
+ 0.3

DD
DD

DD
DD

0.6

0.4

1.5

0.8

1.6 2.7 2.3 V @ 2 MHz Max

Protection*

V

V

I

IL

I

OL

Note:

Trip-Point Voltage* 4.0V

TP

Input Open-Circuit

OC

Voltage

Input Leakage 3.0V

Output Leakage 4.0V

4.5V 1.5

5.5V

6.0V

4.5V

5.0V

5.5V

6.0V

1.9

2.1

0.95

1.05

1.15

1.25
–1.0

5.5V

6.0V

–1.0
–1.0

–1.0

5.5V

6.0V

–1.0
–1.0

0.4 V

2.1

2.5

2.7

1.15

1.25

1.39

1.49

1.0

1.0

1.0

1.0

1.0

1.0

DD

*The Z86318 is functional to VLV voltage. The minimum operational VDD is determined by the value of the VLV voltage at
ambient temperature. The V

voltage increases as temperature decreases.

LV

Typical

2.0

3.0

0.8

1.5

1.6

2.6

1.4

2.6

0.8

1.5

1.3

2.4

2.8

4.4

0.2

0.1

0.8

0.3

1.8

2.2

2.4

1.04

1.15

1.27

1.37

0.4

0.4

0.4

0.4

0.4

0.4

< 250 µ A (Port Pins Only)

IN

VVDriven by External Clock Generator

VVDriven by External Clock Generator

V
V

V
V

V
V

V
V

VVI

= –2.0 mA

OH

VVIOL = +4.0 mA

VVIOL = 20.0 mA, 3 Pin Max

= 10.0 mA, 6 Pin Max

OL

VVP24-P27

V
V

VVNo Off-Chip Resistance

V
V

µA

VIN = 0V, VCC

µA
µA

µA

VIN = 0V, VCC

µA
µA

P R E L I M I N A R Y

5

Z86318
Z8® MCU 8-Bit Microcontroller

DC ELECTRICAL CHARACTERISTICS (Continued)

TA= 0°C to +70°C

Sym. Parameter

I

DD

I

DD1

I

DD2

I

PU

Supply Current 4.0V

Standby Current 4.0V

Standby Current 6.0V 10 1.5 mA STOP mode VIN = 0V, V

Pull-Up Current (100K)

Port P00–P02;

V

DD

4.0V

4.0V

6.0V

6.0V

6.0V

4.0V

4.0V

6.0V

6.0V

6.0V

4.5V

6.0V

Min. Max. @ 25°C Units Conditions Notes

1.5

2.0

3.0

3.0

4.0

6.0

0.6

0.8

1.0

1.3

1.5

2.0

-20
105

Port P22, P23;

Port P31–P33

I

PD

Pull-Down Current (100K)

Port P00–P02;

4.5V

6.0V

20

114

Port P22, P23;

Port P31–P33

I

I

PU

PD

Pull-Up Current (10K)

Port P20, P21

Pull-Down Current (10K)

Port P20, P21

4.5V

6.0V

4.5V

6.0V

208

870

170

870

Note: [1] All outputs unloaded, I/O pins floating, inputs at rail.

Typical

0.41

0.93

1.64

1.44

2.60

4.28

0.15

0.20

0.3

0.70

0.80

1.0

mA

@ 1 MHz

mA

@ 2 MHz

mA

@ 4 MHz

mA

@ 1 MHz

mA

@ 2 MHz

mA

@ 4 MHz

mA

HALT mode VIN = 0V, VCC @ 1 MHz

mA

HALT mode V

mA

HALT mode V

mA

HALT mode V

mA

HALT mode V

mA

HALT mode V

µAV

IH

V

IH

@ 1V

@ 1V

= 0V, VCC @ 2 MHz

IN

= 0V, VCC @ 4 MHz

IN

= 0V, VCC @ 1 MHz

IN

= 0V, VCC @ 2 MHz

IN

= 0V, VCC @ 4 MHz

IN

µAVIL @ 3V

V

@ 4V

IL

µAVIH @ 0V

V

@ 0V

IH

µAVIH @ 3V

V

@ 3V

IH

[1]
[1]
[1]

[1]
[1]
[1]

CC

6 P R E L I M I N A R Y

1

AC ELECTRICAL CHARACTERISTICS

Timing Diagrams

Z86318

Z8® MCU 8-Bit Microcontroller

Clock

T

IN

IRQ

1

2 2 3

7 7

4

N

8

5

6

9

3

Figure 4. Electrical Timing Diagram

P R E L I M I N A R Y 7

Z86318
Z8® MCU 8-Bit Microcontroller

AC ELECTRICAL CHARACTERISTICS

(VDD = 4V to 6V ±10%, TA = 0°C to +70°C, unless otherwise specified)

T

= 0°C to +70°C

A

1 MHz 4 MHz

No. Symbol Parameter

V

DD

Min. Max. Min. Max. Units Notes

1 TpC Input Clock Period 6.0V 1,000 100,000 250 100,000 ns [1]
2 TrC,TfC Clock Input Rise

6.0V 25 25 ns

and Fall Times
3 TwC Input Clock Width 6.0V 475 100 ns [1]
4 TwTinL Timer Input Low Width 6.0V 70 70 ns [1]
5 TwTinH Timer Input High Width 6.0V 2.5TpC 2.5TpC [1]
6 TpTin Timer Input Period 6.0V 4TpC 4TpC [1]
7 TrTin,

TtTin

8 TwIL Int. Request Input

Timer Input Rise

and Fall Timer

6.0V 100 100 ns [1]

6.0V 70 70 ns [1,2]

Low Time
9 TwIH Int. Request Input

6.0V 2.5TpC 2.5TpC [1,2]

High Time
10 T wdt Watch-Dog Timer 6.0V 24 24 ms
11 T

Notes:

1. Timing Reference uses 0.9 VDD for a logic 1 and 0.1 VDD for a logic 0.

2. Interrupt request through Port 3 (P33-P31).

POR

Power-On Reset Time 6.0V 6 6 ms [1]

8 P R E L I M I N A R Y

1

PIN FUNCTIONS

Z86318

Z8® MCU 8-Bit Microcontroller

XTAL1, XTAL2. Crystal in, crystal out (time-based input

and output, respectively). These pins connect a parallel­resonant crystal, LC, or an external single-phase clock (4
MHz Max.) to the on-chip clock oscillator and buffer. Note:
XTAL1 has a pull-down resistor.

/OEN

Port 0 (P02-P00). Port 0 is a 3-bit, I/O programmable, bi­directional, CMOS-compatible I/O port. These three I/O
lines can be configured under software control to be input
or output (see Figure 5). When Port 0 is configured as an
input port, all lines have the capability to be globally con­figured (ROM mask option) for a 100K pull-down or pull-up
resistor. The pull-up/pull-down resistor can be disabled as
well. (No current is drawn if disabled.) Graphs showing
current versus pin voltage are shown in Figures 6 and 7.

Pull-Up

Enable

Pad

Out

In

Pull-Down

Enable

Figure 5. Port 0 Configuration

P R E L I M I N A R Y 9

Z86318
Z8® MCU 8-Bit Microcontroller

PIN FUNCTIONS (Continued)

Figure 6. Typical Current Versus Pin Voltage Values

10 P R E L I M I N A R Y

Z86318

1

Z8® MCU 8-Bit Microcontroller

Figure 7. Typical Current Versus Pin Voltage Values

P R E L I M I N A R Y 11

Z86318
Z8® MCU 8-Bit Microcontroller

PIN FUNCTIONS (Continued)

Port 2 (P27-P20). Port 2 is an 8-bit, bit-programmable, bi-

directional, CMOS-compatible I/O port. P23-P20 can be
configured under software control to be input or output, in­dependently. Note: Bits D3 and D4 of POIM register must
be set to 0. Bits programmed as outputs may be globally
programmed as either push-pull or open-drain via bit D0,
P3M register. P20 and P21 can be configured with a ROM
mask option for 10 Kohm pull-up/pull-down, or none. P22
and P23 can be configured with a ROM mask option for
100 Kohm pull-up/pull-down, or none (Figure 8). No cur-

/Open-Drain

/OEN

rent is drawn if pull-up/pull-down is disabled. Note: P23-20
are configured for pull-up/pull-down/none globally.

P24-P27 can be configured as a voltage divider. The volt­age divider consists of an internal 25K pull-up resistor (Fig­ure 9), and a 7.5K pull-down resistor. The zero trip-point in­put levels on P24-P27 are adjusted for connection to the
emitters of opto-transistors and switch at a voltage level of

0.4 VDD. All four of the voltage dividers are globally con­figured as enabled or disabled.

Pull-Up

Enable

Out

In

Pull-Down

Enable

Note: P20, P21: 10K Pull-Up/Down or none.
P22, P23: 100K Pull-Up/Down or none.
P23-20 are globally selected for Pull-Up/Down or none.

Figure 8. Port 2 P20-P23 Configuration

Pad

12 P R E L I M I N A R Y

Z86318

1

Z8® MCU 8-Bit Microcontroller

Divenb

/Open-Drain

/OE

Out

In

Resistance Tolerance (0 - +40°C)

Typ.

7.5K8.9K
25K30K

Pull-Down

Pull-Up

Min. Max.

5.2K
18K

25K

7.5K

Pad

0.4 VDD

Trip Point Buffer

Figure 9. Port 2 P27-P24 Configuration

Port 3 (P33, P32, P31). Port 3 is a 3-bit, CMOS-compati-

ble port with three fixed input lines (P33–P31). These three
lines can also be used as the interrupt sources IRQ2,
IRQ1, and IRQ0. P31 can also be configured as a timer in­put.

All three lines can be configured globally by means of ma
ROM mask option for a 100 Kohm pull-up or pull-down re­sistor (Figure 10), or no pull-up/pull-down. No current is
drawn if pull-up/pull-down is disabled.

P R E L I M I N A R Y 13

Z86318
Z8® MCU 8-Bit Microcontroller

PIN FUNCTIONS (Continued)

Pad

P31

Pull-Up
Enable

Data Latch
IRQ2, TIN

Pull-Down
/Enable

Pad

Pad

P32

P33

Pull-Down
/Enable

Pull-Up
Enable

Pull-Down
/Enable

Pull-Up
Enable

Data Latch

Data Latch

IRQ1

Figure 10. Port 3 P31-P33 Configuration

14 P R E L I M I N A R Y

Z86318

1

Z8® MCU 8-Bit Microcontroller

The Z86318 MCU incorporates the following special fea­tures to enhance the Z8® architectural core for use in
mouse and trackball applications.

Reset. The Z86318 is reset in one of the following condi­tions: 1) Power-On Reset (POR), 2) Watch-Dog Timer
(WDT) Mode, 3) Stop-Mode Recovery source, and 4) Low­Voltage Recovery. Other sources of Reset, ports are con­figured in an input mode, asynchronous of the clock. How­ever, a clock is required to generate the internal reset that
resets the internal registers.

Auto POR circuitry is built into the Z86318, eliminating the
need for an external reset circuit to reset on power-on.

Table 2. Z86318 Control Registers

Reset Values

Addr.Reg. D7 D6 D5 D4 D3 D2 D1 D0 Comments

F1 TMR00000000
F2 T1 UUUUUUUU
F3 PRE1 UUUUUU00
F4 T0 UUUUUUUU
F5 PRE0 UUUUUUU0
F6*P2M 11111111Inputs after

reset
F7* P3M UUUUUU10
F8* P01M UUU0UU01
F9 IPR UUUUUUUU
FA IRQ UU000000
FB IMR 0UUUUUUU
FC FLAGSUUUUUUUU
FD RP UUUUUUUU
FF SPL UUUUUUUU

Notes: *

A reset after a Low on P27 to exit STOP mode may
affect device reliability.

Program Memory. The Z86318 device can address up to
3 KB of internal program memory (Figure 11). The first 12
bytes of Program Memory are reserved for the interrupt
vectors. These locations contain four 16-bit vectors that
correspond to the four available interrupts. Bytes 0-3064
are programmed on-chip by means of a ROM mask option.

3064

Location of

First Byte of

Instruction

Executed

After RESET

Interrupt

Vector

(Lower Byte)

Interrupt

Vector

(Upper Byte)

12
11
10

9
8
7
6
5
4
3
2
1
0

On-Chip

ROM

IRQ5
IRQ5
IRQ4
IRQ4

Reserved

Reserved

IRQ2
IRQ2
IRQ1
IRQ1

Reserved

Reserved

Figure 11. Program Memory Map

P R E L I M I N A R Y 15

Z86318
Z8® MCU 8-Bit Microcontroller

FUNCTIONAL DESCRIPTION

Register File. The Register File consists of three I/O port

registers, 124 general-purpose registers, and 15 control
and status registers, R0-R3, R4-R127 and R241-R255, re­spectively (see Figure 12). The Z86318 instructions can
access registers directly or indirectly via 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 divided into eight
working register groups, each occupying 16 continuous lo­cations. The Register Pointer addresses the starting loca­tion of the active working-register group (Figures 13 and

14).

LOCATION IDENTIFIERS

R255
R254
R253
R252
R251

R250
R249
R248

R247
R246
R245

R244
R243
R242

R241

Stack Pointer (Bits 7-0)

General-Purpose

Register Pointer

Program Control Flags

Interrupt Mask Register

Interrupt Request Register

Interrupt Priority Register

Ports 0-1 Mode

Port 3 Mode
Port 2 Mode

T0 Prescaler

Timer/Counter0

T1 Prescaler

Timer/Counter1

Timer Mode

SPL
GPR
RP
FLAGS
IMR
IRQ
IPR
P01M
P3M
P2M
PRE0
T0
PRE1
T1
TMR

r7 r6 r5 r4 R253

The upper nibble of the register file address
provided by the register pointer specifies
the active working-register group.

FF

F0

7F

70
6F

60
5F

50
4F

40
3F

30
2F

20

1F

10

0F

00

Register Group F

Specified Working

Register Group

Register Group 1

Register Group 0

r3 r2 r1 r0

I/O Ports

Figure 13. Register Pointer

(Register Pointer)

R15 to R0

The lower nibble
of the register
file address
provided by the
instruction points
to the specified
register.

R15 to R0

R15 to R4
R3 to R0

Not Implemented

R128

R127

R4
R3

R2
R1

R0

General-Purpose

Registers

Port 3
Port 2

Reserved

Port 0

P3
P2

P0

Figure 12. Register File

16 P R E L I M I N A R Y

Z86318

1

Z8® MCU 8-Bit Microcontroller

7

Working Register

Group Pointer

% FF

% FO

% EO

% 7F

% 0F

% 00

REGISTER POINTER

6543210

Bits 0-3 must be 0

Z8 Register File

Z8® STANDARD CONTROL REGISTERS

RESET CONDITION

D7 D6

REGISTER

% FF
% FE
% FD
% FC
% FB
% FA
% F9
% F8

% F7

*

% F6

*

% F5
% F4
% F3
% F2
% F1
% F0

SPL
GPR
RP
FLAGS
IMR
IRQ
IPR
P01M
P3M
P2M
PRE0
T0
PRE1
T1
TMR

Reserved

REGISTER

% (0) 03

*

% (0) 02

*

% (0) 01
% (0) 00

Notes:

All addresses are in Hexadecimal
U = Unknown
* Will not be reset with a Stop-Mode Recovery

P3
P2
Reserved
P0

D5 D4

U

U

U

U

U
0

U

0

0

U
0
0

1
UUUUU

UUUUUUUU
UUU

UUUUUUU
0

U

U

U

0

0

0

U

U

U

U

U

U

0

0

0

U

U

U
0

1

0

0

0

0

1

1

1

UUUUU

000000

0

RESET CONDITION

00 00UU

UUUUUU

UU

UUU

UUU

D3 D2 D1

U

U
U

U

0

0

U

U

U

U

0

0

U

U

1

1

0

0
1

1

UU

D0

U

U
U

U

0

0
U

U

U

U

0

0

U

U

0

1

0

0
1

1

U

U

UU

UU

Figure 14. Register File Architecture

ROM Protect. A ROM Protect feature prevents “dumping”

of the ROM contents without inhibiting execution of LDC,
LDCI, LDE, and LDEI instructions. This feature is mask­programmable.

Stack Pointer. The Z86318 features an 8-bit Stack Point­er (R255) used for the internal stack that resides within the
124 general-purpose registers.

Counter/Timer. There are two 8-bit programmable
counter/timers (T0 and T1), each driven by its own 6-bit
programmable prescaler. The T1 prescaler can be driven
by internal or external clock sources, however, the T0 can
be driven by the internal clock source only (see Figure 15).

The 6-bit prescalers can divide the input frequency of the
clock source by any integer number from 1 to 64. Each
prescaler drives its counter, which decrements the value
(1 to 256) that has been loaded into the counter. When
both counter and prescaler reach the end of count, a timer
interrupt request IRQ4 (T0) or IRQ5 (T1) is generated.

P R E L I M I N A R Y 17

Z86318
Z8® MCU 8-Bit Microcontroller

FUNCTIONAL DESCRIPTION (Continued)

The counter can be programmed to start, stop, restart to
continue, or restart from the initial value. The counters can
also be programmed to stop upon reaching zero (single
pass mode) or to automatically reload the initial value and
continue counting (modulo-n continuous mode).

The counters, but not the prescalers, may be read at any
time without disturbing their value or count mode. The

Write Write Read

PRE0

Initial Value

Register

OSC

6-Bit

÷4

Internal
Clock

External Clock

Down

Counter

clock source for T1 is user-definable and can be either the
internal microprocessor clock divided by four, or an exter­nal signal input via Port 3. The Timer Mode register config­ures the external timer input (P31) as an external clock, a
trigger input that is retriggerable or not retriggerable, or as
a gate input for the internal clock.

Internal Data Bus

T0

Initial Value

Register

8-Bit

Down

Counter

T0

Current Value

Register

IRQ4

Clock

Logic

T P31

IN

÷4

Internal Clock
Gated Clock
Triggered Clock

Write

6-Bit

Down

Counter

PRE1

Initial Value

Register

Write

8-Bit

Down

Counter

T1

Initial Value

Register

Internal Data Bus

Figure 15. Counter/Timers Block Diagram

IRQ5

T1

Current Value

Register

Read

18 P R E L I M I N A R Y

Z86318

1

Z8® MCU 8-Bit Microcontroller

Interrupts. The Z86318 features four interrupts from four

different sources. These interrupts are maskable and pri­oritized (Figure 16). The four sources are divided as fol­lows: the falling edge of P31, P33, and the two counter/tim­ers. The Interrupt Mask Register globally or individually
enables or disables the four interrupt requests (Table 4).

When more than one interrupt is pending, priorities are re­solved by a programmable priority encoder that is con­trolled by the Interrupt Priority register. All Z86318 inter­rupts are vectored through locations in program memory.
When an interrupt machine cycle is activated, an interrupt
request is granted. This disables all subsequent interrupts,
saves the Program Counter and Status Flags, and then
branches to the program memory vector location reserved
for that interrupt. This memory location and the next byte
contain the 16-bit starting address of the Interrupt Service
Routine for that particular interrupt request.

To accommodate polled interrupt systems, interrupt inputs
are masked and the Interrupt Request Register is polled to
determine which of the interrupt requests needs service.

Table 3. Interrupt Types, Sources, and Vectors

Source Name Vector Location Comments

P33 IRQ1 2,3 External (F)Edge
P31 IRQ2 4,5 External (F)Edge
T0 IRQ4 8,9 Internal
T1 IRQ5 10,11 Internal

Notes:

F = Falling edge triggered
R = Rising edge triggered

IRQ0 - IRQ5

IRQ

Global

Interrupt

Enable

Interrupt
Request

Figure 16. Interrupt Block Diagram

Clock. The Z86318 on-chip oscillator has a parallel-reso-

nant amplifier for connection to a crystal, ceramic resona­tor, or any suitable external clock source (XTAL1 = Input,
XTAL2 = Output). The crystal should be AT cut, 4 MHz
max, with a series resistance (RS) less than or equal to
100 Ohms.

IMR

6

IPR

Priority

Logic

Vector Select

The crystal should be connected across XTAL1 and
XTAL2 using the recommended capacitors (capacitance is
between 10 pF to 250 pF and is specified by the crystal
manufacturer, ceramic resonator and PCB layout) from
each pin to ground (see Figure 17).

P R E L I M I N A R Y 19

Z86318
Z8® MCU 8-Bit Microcontroller

FUNCTIONAL DESCRIPTION (Continued)

XTAL1

C1

C1

XTAL2

C2

C2

Ceramic
Resonator
or Crystal

Figure 17. Oscillator Configuration

HALT Mode. This instruction turns off the internal CPU

clock but not the on-chip oscillation circuit. The
counter/timers and external interrupts IRQ1 and IRQ2 re­main active. The device can be recovered by interrupts, ei­ther externally or internally generated. An interrupt request
must be executed (enabled) to exit HALT mode. After the
interrupt service routine, the program continues from the
instruction after the HALT. The HALT mode may also be
exited via POR/RESET activation or a WDT time-out. In
this case, the program execution begins at location
000CH. The WDH instruction is used to enable the Watch­Dog Timer in HALT mode.

STOP Mode. This instruction turns off the internal clock
and reduces the standby current. The STOP mode can be
released by the following methods: 1) Power-On Reset
(POR) and 2) P27 is configured as an input line when the
device executes the STOP instruction. A low input condi­tion on P27 that meets a minimum pulse width (TWSM) re­leases the STOP mode. Note: WDT is disabled in STOP
mode.

XTAL1

XTAL1

L

XTAL2

LC Clock

In order to enter STOP (or HALT) mode, it is necessary to
first flush the instruction pipeline to avoid suspending exe­cution in mid-instruction. To do this, the user must execute
a NOP (opcode=FFH) immediately before the appropriate
sleep instruction, such as the following:

FF NOP ; clear the pipeline
6F STOP ; enter the STOP

FF NOP ; clear the pipeline
7F HALT ; enter the HALT

In STOP or HALT mode, the value of each output line prior
to the HALT or STOP instruction is retained during execu­tion.

External Clock

XTAL2

mode
or

mode

Upon reset, program execution begins at location 000C
(hex). However, when P27 is used to release the STOP
mode, the I/O port mode registers are not reconfigured to
their default power-on conditions. This prevents any I/O,
configured as an output when the STOP instruction was
executed, from glitching to an unknown state. To use the
P27 release approach with STOP mode, use the following
instruction:

LDP2M, #1XXX XXXXB(X = user's choice)
NOP
STOP

20 P R E L I M I N A R Y

Z86318

1

Z8® MCU 8-Bit Microcontroller

Watch-Dog Timer (WDT). The WDT is initially enabled by

executing the WDT instruction and it is refreshed by sub­sequent WDT instruction executions. Note: Once the WDT
has been enabled, it cannot be disabled. The time-out pe­riod of the WDT is 24 ms. The WDT instruction affects the
Zero (Z), Sign (S), and Overflow (V) flags. The WDT can
be permanently enabled (ROM mask option) upon MCU
power-up.

Opcode WDT (5FH). Execution of WDT clears the WDT
counter. This must be done at least every 24 ms, other­wise, the WDT times out and generates a reset. This gen­erated reset is the same as a power-on reset of 6.0 ms,
plus 18 clock cycles.

Vcc

(Volts)

2.80

2.75

2.70

Low-Voltage Protection (VLV). The device will function
normally between 6.0V and 4.0V under all specified condi­tions. Below 4.0V, the device is still internally functional un­til the Low Voltage trip point (VLV) is reached; however, it
is not guaranteed to meet all AC and DC Characteristics.
When the supply voltage drops below VLV, an automatic
hardware reset occurs, re-initializing the Z86318. The
Low-Voltage Protection feature may be selected as a
ROM mask option.

The actual VLV is a function of temperature, operating fre­quency and process parameters. A typical example of the

trip-point function at ambient temperature for a fre-

V

LV

quency of 4 MHz is illustrated in Figure 18.

2.65
LLV (Typical)

2.60

2.55

2.50
–5 0 5 10 15 20 25 30 35 40 45

Temperature (°C)

Figure 18. Typical Z86318 V

Versus Temperature

LV

P R E L I M I N A R Y 21

Z86318

t

0 T0 Single Pass
1 T0 Modulo N

D7 D6 D5 D4 D3 D2 D1 D0

Count Mode

Reserved (Must be 0)
Prescaler Modulo

(Range: 1-64 Decimal
01-00 HEX)

R245 PRE0

0 Port 2 Open-Drain
1 Port 2 Push-Pull

D7 D6 D5 D4 D3 D2 D1 D0

Reserved (Must be 0)

R247 P3M

Z8® MCU 8-Bit Microcontroller

Z8 CONTROL REGISTERS

R241 TMR

D7 D6 D5 D4 D3 D2 D1 D0

0 No Function
1 Load T0

0 Disable T0 Count
1 Enable T0 Count

0 No Function
1 Load T1

0 Disable T1 Count
1 Enable T1 Count

TIN Modes
00 External Clock Input
01 Gate Input
10 Trigger Input
(Non-retriggerable)
11 Trigger Input
(Retriggerable)

Reserved (Must be 0)

Figure 19. Timer Mode Register (F1H:Read/Write)

R242 T1

D7 D6 D5 D4 D3 D2 D1 D0

R244 T0

D7 D6 D5 D4 D3 D2 D1 D0

T0 Initial Value
(When Written)
(Range: 1-256 Decimal
01-00 HEX)
T0 Current Value
(When READ)

Figure 22. Counter Timer 0 Register (F4H: Read/Write)

Figure 23. Prescaler 0 Register (F5

: Write Only)

H

Figure 20. Counter Timer 1 Register (F2

R243 PRE1

D7 D6 D5 D4 D3 D2 D1 D0

Figure 21. Prescaler 1 Register (F3

T1 Initial Value
(When Written)
(Range 1-256 Decimal
01-00 HEX)
T1 Current Value
(When READ)

: Read/Write)

H

Count Mode
0 T1 Single Pass
1 T1 Modulo

Clock Source
1 T1 Internal
0 T1 External Timing Inpu
(TIN) Mode

Prescaler Modulo
(Range: 1-64 Decimal
01-00 HEX)

:Write Only)

H

R246 P2M

D7 D6 D5 D4 D3 D2 D1 D0

P27- P20 I/O Definition
0 Defines Bit as OUTPUT
1 Defines Bit as INPUT

Figure 24. Port 2 Mode Register (F6

Figure 25. Port 3 Mode Register (F7

: Write Only)

H

: Write Only)

H

22 P R E L I M I N A R Y

Z86318

1

Z8® MCU 8-Bit Microcontroller

R248 P01M

D7 D6 D5 D4 D3 D2 D1 D0

Figure 26. Port 0 and 1 Mode Register

(F8H: Write Only)

R249 IPR

D7 D6 D5 D4 D3 D2 D1 D0

Reserved
(Must be 0.)

P00-P03 Mode
00 Output

01 Input
Reserved (Must be 0)
Reserved (Must be 0)

0000

Reserved

0001

IRQ1>4>5>2

0010

Reserved

0011

IRQ4>1>5>2

0100

IRQ5>2>1>4

0101

IRQ5>1>4>2

0110

IRQ5>2>4>1

0111

IRQ5>4>1>2

1000

IRQ2>1>4>5

1001

IRQ1>4>2>5

1010

IRQ2>4>1>5

1011

IRQ4>1>2>5

1100

IRQ2>5>1>4

1101

Reserved

1110

IRQ2>5>4>1

1111

Reserved

R251 IMR

D7 D6 D5 D4 D3 D2 D1 D0

1 Enables IRQ5-IRQ0
(D0 = IRQ0)

Reserved (Must be 0)
1=Global Interrupt Enable

0=Global Interrupt Disable

Figure 29. Interrupt Mask Register (FBH: Read/Write)

R252 Flags

D7 D6 D5 D4 D3 D2 D1 D0

User Flag F1
User Flag F2

Half Carry Flag
Decimal Adjust Flag

Overflow Flag
Sign Flag
Zero Flag
Carry Flag

Figure 30. Flag Register (FC

: Read/Write)

H

Figure 27. Interrupt Priority Register (F9

R250 IRQ

D7 D6 D5 D4 D3 D2 D1 D0

Reserved (Must be 0)
IRQ1 = P33 Input

IRQ2 = P31 Input
Reserved (Must be 0)
IRQ4 = T0
IRQ5 = T1

Reserved (Must be 0)

Figure 28. Interrupt Request Register

(FA

: Read/Write)

H

: Write Only)

H

R253 RP

D7 D6 D5 D4 D3 D2 D1 D0

Reserved (Must be 0)
Working Register Pointer

Figure 31. Register Pointer (FD

R255 SPL

D7 D6 D5 D4 D3 D2 D1 D0

: Read/Write)

H

Stack Pointer Lower
Byte (SP0-SP7)

Figure 32. Stack Pointer (FFH: Read/Write)

P R E L I M I N A R Y 23

Z86318
Z8® MCU 8-Bit Microcontroller

PACKAGE INFORMATION

Figure 33. 18-Pin DIP Package Diagram

Figure 34. 18-Pin SOIC Package Diagram

24 P R E L I M I N A R Y

1

ORDERING INFORMATION

Z86318

18-Pin DIP 18-Pin SOIC

Z8631804PSC Z8631804SSC
Z8631804PEC Z8631804SEC

For fast results, contact your local Zilog sales offices for
assistance in ordering the part desired.

Codes
Preferred Package

P = DIP

Longer Lead Time

S = SOIC

Temperature

S = 0°C to +70°C

Z86318

Z8® MCU 8-Bit Microcontroller

Speed

04 = 4 MHz

Environmental

C = Plastic Standard

Example:

Z 86318 04 P S C

is a Z86318, 4 MHz, DIP, 0°C to +70°C, Plastic Standard Flow

Environmental Flow
Temperature
Package
Speed
Product Number

P R E L I M I N A R Y 25

Z86318
Z8® MCU 8-Bit Microcontroller

26 P R E L I M I N A R Y