IOtech Digital488 User manual

Digital488 IEEE 488 to Digital Interface
INSTRUCTION MANUAL
IOtech, Inc. • 25971 Cannon Road • Cleveland, Ohio 44146 • [phone]

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Warnings, Cautions, Notes, and Tips
Refer all service to qualified personnel. This caution symbol warns of possible personal injury or equipment damage
under noted conditions. Follow all safety standards of professional practice and the recommendations in this manual.
Using this equipment in ways other than described in this manual can present serious safety hazards or cause equipment
damage.
This ESD caution symbol urges proper handling of equipment or components sensitive to damage from electrostatic
discharge. Proper handling guidelines include the use of grounded anti-static mats and wrist straps, ESD-protective
bags and cartons, and related procedures.
Specifications and Calibration
Specifications are subject to change without notice. Significant changes will be addressed in an addendum or revision to the manual. As applicable, IOtech calibrates its
hardware to published specifications. Periodic hardware calibration is not covered under the warranty and must be performed by qualified personnel as specified in this
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welcomes your suggestions.

Digital488
and
Digital488OEM
Instruction Manual
110-0920
Revision 4.2
November 1990
IOtech, Inc. ●25971 Cannon Road ●Cleveland, Ohio 44146 ●[phone]

Table of Contents
Section1 Introduction Page
1.1 General Description 1.1
1.2 Available Accessories1.2
1.3 Specifications 1.3
1.4 Abbreviations 1.5
Section 2 Getting Started Page
2.1 Inspection 2.1
2.2 Configuration 2.1
2.2.1 IEEE Address Selection 2.2
2.2.2 IEEE Bus Output Terminator Selection 2.3
2.3 Digital Input/Output Ports 2.4
2.3.1 Logic Levels 2.4
2.3.2 Digital I/O Port Pin Outs 2.4
2.3.3 Control Lines 2.6
2.3.3.1 Clear 2.6
2.3.3.2 Data Strobe 2.7
2.3.3.3 External Data Ready 2.7
2.3.3.4 Inhibit 2.8
2.3.3.5 Trigger 2.9
2.3.3.6 Service 2.9
2.4 IEEE 488 Bus Implementation 2.9
2.4.1 My Talk Address (MTA) 2.10
2.4.2 My Listen Address (MLA) 2.11
2.4.3 Device Clear (DCL and SDC) 2.11
2.4.4 Group Execute Trigger (GET) 2.11
2.4.5 Interface Clear (IFC) 2.12
2.4.6 Serial Poll Enable (SPE) 2.12
2.4.7 Serial Poll Disable (SPD) 2.12
2.4.8 Unlisten (UNL) 2.12
2.4.9 Untalk (UNT) 2.12
2.5 Installation 2.13
Section 3 Command Descriptions Page
Introduction 3.1
Bit Set (An) 3.2
Bit Clear (Bn) 3.3
Bus Input/Output (Gn) 3.4

Table of Contents
Section 3 Command Descriptions Page
Configure (Cn) 3.5
Data (D...Z) 3.6
Data Ready (Rn) 3.8
End or Identify (Kn) 3.9
Execute (X) 3.10
Format (Fn) 3.11
Handshake (Hn) 3.18
Inhibit (Qn) 3.19
Invert (In) 3.20
Port (Pn) 3.21
Service Request Mask (Mn) 3.22
Serial Poll Status Byte 3.24
Status (Un) 3.26
Terminator (Yn) 3.29
Test (T0) 3.30
Section 4 IEEE 488 Primer Page
4.1 History 4.1
4.2 General Structure 4.1
4.3 Send It To My Address 4.4
4.4 Bus Management Lines 4.4
4.4.1 Attention (ATN) 4.4
4.4.2 Interface Clear (IFC) 4.5
4.4.3 Remote Enable (REN) 4.5
4.4.4 End Or Identify (EOI) 4.5
4.4.5 Service Request (SRQ) 4.5
4.5 Handshake Lines 4.6
4.5.1 Data Valid (DAV) 4.6
4.5.2 Not Ready For Data (NRFD) 4.6
4.5.3 Not Data Accepted (NDAC) 4.6
4.6 Data Lines 4.7
4.7 Multiline Commands 4.7
4.7.1 Go To Local (GTL) 4.7
4.7.2 Listen Address Group (LAG) 4.8
4.7.3 Unlisten (UNL) 4.8
4.7.4 Talk Address Group (TAG) 4.8
4.7.5 Untalk (UNT) 4.8

Table of Contents
Section 4 IEEE 488 Primer Page
4.7.6 Local Lockout (LLO) 4.8
4.7.7 Device Clear (DCL) 4.8
4.7.8 Selected Device Clear (SDC) 4.9
4.7.9 Serial Poll Disable (SPD) 4.9
4.7.10 Serial Poll Enable (SPE) 4.9
4.7.11 Group Execute Trigger (GET) 4.9
4.7.12 Take Control (TCT) 4.9
4.7.13 Secondary Command Group (SCG) 4.9
4.7.14 Parallel Poll Configure (PPC) 4.10
4.7.15 Parallel Poll Unconfigure (PPU) 4.10
4.8 More On Service Requests 4.10
4.8.1 Serial Poll 4.11
4.8.2 Parallel Poll 4.11
Section 5 Service Information Page
5.1 Factory Service 5.1
5.2 Theory of Operation 5.1
5.3 Digital488 Mother Board Component Layout 5.3
5.4 Digital488 I/O Board Component Layout 5.4
5.5 Digital488OEM Component Layout 5.5
5.6 Digital488 Parts List 5.6
5.7 Digital488OEM Parts List 5.8
Appendix A Digital488 Command Summary
Appendix B IEEE Command and Address Messages
Appendix C Digital488OEM Mechanical Dimensions

Section 1 Introduction
1.1
Introduction
1.1 General Description
The Digital488 is a digital input and output interface to the IEEE 488 bus.
Each unit has 40 TTL level digital I/O lines, which are divided into 5 eight-bit ports.
Each port is software programmable as input or output. The Digital488OEM is a
board level interface with the same capabilities as the Digital488. All descriptions in
this manual refer to both products unless otherwise stated. When the model number
Digital488 is used in this manual, Digital488OEM is also implied.
The Digital488 has several features which give it versatile interface
capability. A trigger output signal is asserted on the Group Execute Trigger (GET)
command. Edge-triggered inputs can generate a Service Request on the bus. Six data
formats are software programmable, including ASCII hexadecimal, ASCII character,
ASCII binary, binary, high speed binary and ASCII decimal. There are also
individual bit set and bit clear commands. Programmable terminators are provided
to facilitate interfacing to various controllers.
A status mode enables the controller to interrogate the programmed status of
the Digital488 at any time. A self-test is initiated at power-on which checks for
proper RAM and ROM operation.
When addressed to talk, the Digital 488 will output data from all forty bits or
a selected 8 bit port. When addressed to listen, the unit will input data and
programming information from the controller, and output the data to the appropriate
I/O port.

Section 1 Introduction
1.2
1.2 Available Accessories
Additional accessories that can be ordered for the Digital488 include:
CA-7-1 1.5 foot IEEE 488 Cable
CA-7-2 6 foot IEEE 488 Cable
CA-7-3 6 foot shielded IEEE 488 Cable
CA-7-4 6 foot reverse entry IEEE 488 Cable
CA-8-50† 6 foot, 50 conductor ribbon cable with a card edge
connector on one end, the other end un-terminated.
CN-6-50† 50 Pin solder tab edge connector.
CN-20 Right Angle IEEE 488 adapter, male and female
CN-22 IEEE 488 Multi-tap bus strip, four female connectors in
parallel
CN-23 IEEE 488 panel mount feed-through connector, male
and female
110-0920 Additional Instruction Manual
Rack488-3† 5-1/4" by 19" rack mount for one Digital488
Rack488-4† 5-1/4" by 19" rack mount for two Digital488s
TR-2† 110 volt Wall mount power supply for the Digital488
TR-2E† 220 volt Wall mount power supply for the Digital488
TR-5 110 volt Wall mount power supply for the Digital488OEM
TR-5E 220 volt Wall mount power supply for the Digital488OEM
†For use with Digital488 Only

Section 1 Introduction
1.3a
1.3 Specifications
Digital488 Specifications
Digital I/O Terminal Installation Category:
Standard: Not Applicable. CE: Category 1.
Transistor-Transistor Logic (TTL) Levels:
Outputs will drive 2 TTL loads.
Connector:
One 50-pin card edge (mating connector supplied).
IEEE 488
&$87,21
The IEEE 488 terminal must only be used to control a non-isolated IEEE 488 system.
The common mode voltage (cable shell to earth) must be zero.
Terminal Installation Category:
Standard: Not Applicable. CE: Category 1.
Implementation:
SH1, AH1, T6, TE0, L4, LE0, SR1, RL0, PP0, DC1, DT1, C0, E1.
Terminators:
Selectable CR, LF, LF-CR, and CR-LF with EOI.
Programmable:
IEEE Terminators, EOI, SRQ Mask, Port Data, Active Levels, Handshake Lines, Format and Configuration.
Connector:
Standard IEEE 488 connector with metric studs.
General Configuration:
Five 8-bit ports, programmable as inputs or outputs. Also included are programmable handshake lines, data latching
capability, Clear and Trigger outputs, and a Service Request (SRQ) input.

Section 1 Introduction
1.3b
Terminal Installation Category:
Standard: Not Applicable. CE: Category 1 for all terminals.
Dimensions:
188 mm deep x 140 mm wide x 68 mm high (7.39" x 5.5" x 2.68").
Weight: 1.55 kg. (3.6 lbs).
Operating Environment:
Standard: Indoor, 0°to 50°C; 0 to 70% RH to 35°C. Linearly derate 3% RH/°C from 35 to 50 °C.
CE: Indoor use at altitudes below 2000 meters, 0°to 40°C; 80% maximum RH up to 31°C decreasing linearly 4%
RH/°C to 40°C.
Controls:
Power switch (external), and IEEE parameter switches (internal).
Indicators:
LED indicators for IEEE TALK, LISTEN, SRQ, ERROR, and POWER.
Power:
An external power supply is provided with the Digital488: Input is 105-125 VAC,
or 210-250 VAC; 50/60 Hz, 10 VA maximum. The external power supply 9 VDC output is to be connected to the
Digital488 power input marked: 10 VDC MAX @ 500 mA.
:$51,1*
Do not use this interface outdoors! The interface is intended for indoor use only!
Outdoor conditions could result in equipment failure, bodily injury, or death!
&$87,21
Do not connect AC power line directly to the Digital488. Direct AC connection will
damage equipment.

Section 1 Introduction
1.3c
Digital488/OEM Specifications
:$51,1*
Do not use this interface outdoors! The interface is intended for indoor use only!
Outdoor conditions could result in equipment failure, bodily injury, or death!
&$87,21
Never disassemble the interface case while it is connected to the AC power line!
Internal voltage potentials exist which could cause bodily injury or death!
Digital I/O
Transistor-Transistor Logic (TTL) Levels:
Outputs will drive 2 TTL loads.
Connector:
One 50-pin IDC, organized as two rows of 25 pins.
IEEE 488 Implementation:
SH1, AH1, T6, TE0, L4, LE0, SR1, RL0, PP0, DC1, DT1, C0, E1.
Terminators:
Selectable CR, LF, LF-CR, and CR-LF with EOI.
Programmable:
IEEE Terminators, EOI, SRQ Mask, Port Data, Active Levels, Handshake Lines, Format and Configuration.
Connector:
Standard IEEE 488 connector with metric studs.

Section 1 Introduction
1.3d
General Configuration:
Five 8-bit ports, programmable as inputs or outputs. Also included are programmable
handshake lines, data latching capability, Clear and Trigger outputs, and a Service Request (SRQ) input.
Dimensions:
205 mm deep x 115 mm wide x 28 mm high (8" x 4.5" x 1.1").
Weight: 0.23 kg. (0.5 lbs).
Operating Environment:
Standard: Indoor, 0°to 50°C; 0 to 70% RH to 35°C. Linearly derate 3% RH/°C from 35 to 50 °C.
Controls:
IEEE parameter switches.
Indicators:
LED indicators for IEEE TALK, LISTEN, SRQ, ERROR, and POWER.
Power:
User suupplied +5 volts ±0.25% at 1 amp. Mating power connector with 8 inch leads provided.
:$51,1*
Do not use this interface outdoors! The interface is intended for indoor use only!
Outdoor conditions could result in equipment failure, bodily injury, or death!
&$87,21
Never disassemble the interface case while it is connected to the AC power line!
Internal voltage potentials exist which could cause bodily injury or death!

Section 1 Introduction
1.5
1.4 Abbreviations
The following IEEE 488 abbreviations are used throughout this manual.
addr n IEEE bus address "n"
ATN Attention line
CA Controller Active
CR Carriage Return
data Data String
DCL Device Clear
GET Group Execute Trigger
GTL Go To Local
LA Listener Active
LAG Listen Address Group
LF Line Feed
LLO Local Lock Out
MLA My Listen Address
MTA My Talk Address
PPC Parallel Poll Configure
PPU Parallel Poll Unconfigure
SC System Controller
SDC Selected Device Clear
SPD Serial Poll Disable
SPE Serial Poll Enable
SRQ Service Request
TA Talker Active
TAD Talker Address
TCT Take Control
term Terminator
UNL Unlisten
UNT Untalk
* Unasserted

Section 2 Getting Started
2.1
Getting Started
2.1 Inspection
The Digital488 was carefully inspected, both mechanically and electrically,
prior to shipment. When you receive the interface, carefully unpack all items from
the shipping carton and check for any obvious signs of physical damage which may
have occurred during shipment. Report any such damage found to the shipping agent
immediately. Remember to retain all shipping materials in the event that shipment
back to the factory becomes necessary.
Every Digital488 is shipped with the following....
•Digital488 IEEE Digital I/O Converter or
•Digital488OEM Board Level IEEE Digital I/O Converter
•CN-8-50† Digital I/O Port Mating Connector
•110-0920 Instruction Manual
•Power Supply† TR-2; 115V or
•TR-2E; 220V
†Supplied with Digital488 Only and not the Digital488OEM
2.2 Configuration
The Digital488 has one internal 8 position switch which determines the unit's
IEEE address and its default IEEE bus output terminator. The switch is only read
when the unit is powered on, and should only be set prior to applying power. The
following figure illustrates the factory default setting for SW1.
SW1 Factory Default Settings
OPEN
12345678
1
0DOT
Switch
Side
View
IEEE Address = 18
Terminator = CR-LF
EOI Enabled

Section 2 Getting Started
2.2
To modify any of these defaults, follow this simple procedure. Disconnect the
power supply from the AC line and from the interface. Disconnect any IEEE or
digital I/O cables prior to disassembly.
WARNING
Never open the Digital488 case while it is
connected to the AC line. Failure to observe the
warning may result in equipment failure, personal
injury or death.
Remove the four screws located in each corner of the rear panel. Hold the case
firmly and pull the rear panel outward, noting the slot location of the main circuit
board. Modify those parameters which are appropriate for your installation and
reassemble the unit. Slide the main circuit board into the previously noted slot and
finish reassembly by tightening the four screws into the rear panel.
2.2.1 IEEE 488 Address Selection
The IEEE 488 bus address is set by SW1-1 through SW1-5. The
address can be set from 0 through 30 and is read only at power on. The
address is selected by simple binary weighting with SW1-1 being the least
significant bit and SW1-5 the most significant bit. The factory default is
address 18. If address 31 is selected, it defaults to address 30 because the
IEEE 488 standard has reserved address 31.
SW1 View for IEEE Bus Address Selection
OPEN
12345678
1
0DOT
Switch
Side
View
1 x 16
0 x 8
0 x 4
1 x 2
0 x 1
= 0
= 0
= 2
= 0
+
IEEE Address = 18
= 16

Section 2 Getting Started
2.3
2.2.2 IEEE 488 Bus Output Terminator Selection
The terminating characters sent on output by the Digital488 are
determined by SW1-6 through SW1-8. The terminator switches are read
only at power on, but can be changed by the controller through the
Terminator command. If power is cycled after receipt of the Terminator
command, then the unit will once again default to the switch settings. The
factory default settings are Carriage Return - Line Feed with EOI asserted.
The Digital488 ignores all terminators received from the bus
controller. Only the Execute command (X) is used to signal the Digital488
that a command string has been completed.
SW1 View for Terminator Selection
OPEN
12345678
1
0DOT
Switch
Side
View
OPEN
12345678
1
0
OPEN
12345678
1
0
OPEN
12345678
1
0
CR-LF LF-CR
CR Only LF Only
OPEN
12345678
1
0
OPEN
12345678
1
0
EOI Enabled EOI Disabled

Section 2 Getting Started
2.4
2.3 Digital Input/Output Ports
The Digital488 has 40 data lines which can be programmed in groups of 8 as
either input or output. At power on, all 40 bits are in the input mode. Each 8 bit group
is one port, beginning with Port 1 as the least significant 8 bits, and Port 5 as the most
significant 8 bits.
2.3.1 Logic Levels
The data and handshake output lines will drive two TTL loads. In
addition, ports 1 and 2 outputs are 5 Volt CMOS compatible. All input lines are
less than 1.5 TTL loads. All inputs are protected against damage due to high
static voltages. Normal precautions should be taken to limit the input voltages
to -0.3 to +7.0 volts. All I/O lines are referenced to COMMON (Pin 50).
2.3.2 Digital I/O Port Pin Outs
The following diagram illustrates the digital I/O edge connector as view
from the rear of the Digital488 and the top PC Board edge view of the
Digital488OEM.
Digital488 Rear Panel I/O Connector Pin Out
210 20 30 40 50
4939199129
Clear (O)
Trigger (O)
Service (I)
+5 Volts
[ 50 mA Max!]
Not Used
External Data Ready (I)
Inhibit (O)
Data Strobe (O)
Not Used
Common (GND)
Digital I/O
Bits 1 thru 40
(I)
(O) = Input = Output