Acces ICOM-2S User manual

ACCES I/O PRODUCTS INC
10623 Roselle Street, San Diego, CA 92121
TEL [phone] FAX [phone]
MODEL ICOM-2S
USER MANUAL
FILE: MICOM-2S.Eb

iii
Notice
The information in this document is provided for reference only. ACCES does not assume any liability arising
out of the application or use of the information or products described herein. This document may contain or
reference information and products protected by copyrights or patents and does not convey any license under
the patent rights of ACCES, nor the rights of others.
IBM PC, PC/XT, and PC/AT are registered trademarks of the International Business Machines Corporation.
Printed in USA. Copyright 1995 by ACCES I/O Products Inc, 10623 Roselle Street, San Diego, CA 92121.
All rights reserved.

iv
Warranty
Priortoshipment,ACCESequipmentisthoroughlyinspectedandtestedtoapplicablespecifications. However,
should equipment failure occur, ACCES assures its customers that prompt service and support will be
available. All equipment originally manufactured by ACCES which is found to be defective will be repaired
or replaced subject to the following considerations.
Terms and Conditions
If aunit is suspected of failure, contact ACCES' Customer Service department. Be prepared to give the unit
model number, serial number, and adescription of the failure symptom(s). We may suggest some simple tests
to confirm the failure. We will assign a Return Material Authorization (RMA) number which must appear on
the outer label of the return package. All units/components should be properly packed for handling and
returned with freight prepaid to the ACCES designated Service Center, and will be returned to the
customer's/user's site freight prepaid and invoiced.
Coverage
First Three Years: Returned unit/part will be repaired and/or replaced at ACCES option with no charge for
labor or parts not excluded by warranty. Warranty commences with equipment shipment.
Following Years: Throughout your equipment's lifetime, ACCES stands ready to provide on-site or in-plant
service at reasonable rates similar to those of other manufacturers in the industry.
Equipment Not Manufactured by ACCES
Equipment provided but not manufactured by ACCES is warranted and will be repaired according to the
terms and conditions of the respective equipment manufacturer's warranty.
General
Under this Warranty, liability of ACCES is limited to replacing, repairing or issuing credit (at ACCES
discretion) for any products which are proved to be defective during the warranty period. In no case is
ACCES liable for consequential or special damage arriving from use or misuse of our product. The customer
is responsible for all charges caused by modifications or additions to ACCES equipment not approved in
writing by ACCES or, if in ACCES opinion the equipment has been subjected to abnormal use. "Abnormal
use" for purposes of this warranty is defined as any use to which the equipment is exposed other than that use
specified or intended as evidenced by purchase or sales representation. Other than the above, no other
warranty, expressed or implied, shall apply to any and all such equipment furnished or sold by ACCES.

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Table of Contents
Chapter 1: Introduction ..............................................1-1
Multipoint Opto-isolated Communications ....................................1-1
COM Port Compatibility ..................................................1-1
Line Bias and Termination ...............................................1-1
Auto and Manual Transceiver Control .......................................1-2
Led Monitors ..........................................................1-2
Communication Modes ..................................................1-2
CE Marking ...........................................................1-2
Specifications .........................................................1-3
Chapter 2: Installation ..............................................2-1
CD Installation .........................................................2-1
3.5-Inch Diskette Installation ..............................................2-1
Directories Created on the Hard Disk .......................................2-2
Installing the Card ......................................................2-4
Chapter 3: Option Selection ..........................................3-1
Communication Modes and Cabling Options .................................3-2
Interrupts .............................................................3-2
Chapter 4: Address Selection .........................................4-1
Chapter 5: Programming .............................................5-1
Sample Programs ......................................................5-1
Windows Programming ..................................................5-1
Initialization ...........................................................5-1
Reception ............................................................5-3
Transmission ..........................................................5-4
Chapter 6: Connector Pin Assignments ................................6-1
Appendix A: Application Considerations ..............................A-1
Introduction ...........................................................A-1
Balanced Differential Signals .............................................A-1
RS485 Data Transmission ...............................................A-3

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List of Figures
Figure 1-1: ICOM-2S Block Diagram ..........................................1-4
Figure 3-1: Simplified Schematic .............................................3-1
Figure 3-2: ICOM-2S Option Selection Map .....................................3-3
Figure A-1: Typical RS485 Two-Wire Multidrop Network ...........................A-3
List of Tables
Table 4-1: Standard Address Assignments for 286/386/486 Computers ...............4-1
Table 4-2: ICOM-2S Address Switch Setup .....................................4-2
Table 4-3: Example Address Setup ...........................................4-2
Table 4-4: Standard COM Port Addresses .....................................4-3
Table 5-1: Baud Rate Divisors ...............................................5-2
Table 6-1: Connector Pin Assignments ........................................6-1
Table A-1: Connections Between Two RS422 Devices ............................A-1
Table A-2: RS422 Specification Summary ......................................A-2

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Chapter 1: Introduction
The card is 10 inches long (264 mm) and should be installed in long slots of IBM PC/XT/AT or
compatible computers. If installed in an eight-bit slot, the high interrupts (IRQ 10-15) will not be
available to the ICOM-2S.
Multipoint Opto-isolated Communications
TheICOM-2S Serial InterfaceCard wasdesigned formultipoint transmissionon longcommunication
lines in noisy environments using RS422 or RS485 differential line drivers. The data lines are
opto-isolated from the computer and from each other to assure communication when large common
mode noise are superimposed. Opto-isolators are provided on the RTS and CTS control lines as well
as the transmit and receive lines. Further, an on-board DC-DC converter provides isolated power for
the line driver and RTS and CTS circuits.
Acrystal oscillator is located on the card. This oscillator permits precise selection of baud rate from
50 to 115,200 but the standard opto-isolators are limited to amaximum speed of 38,400 baud. Faster
opto-isolators and custom crystals are available. If your card is modified to handle higher baud rates,
then there will be a"manual addendum" page describing that modification in the front of this manual.
The output transceiver used, type 75176B, is capable of driving extremely long communication lines
at high baud rates. It can drive up to ±60mA on balanced lines and receive inputs as low as ±200mV
differential signal superimposed on common mode noise of ± 12V. However, opto-isolators on the
card provide protection to maximum 500 V. In case of communication conflict, the transceivers
feature thermal shutdown.
COM Port Compatibility
Type NS16550 UARTs are used asthe Asynchronous Communication Element (ACE) which include
a16-byte transmit/receive buffer to protect against lost data in multitasking operating systems, while
maintaining 100% compatibility with the original IBM serial port.
ICOM-2S card is not restricted to the standard DOS addresses of COM1 - COM4. You can select
abase address anywhere within the I/O address range 000 to 3F8 hex and the FINDBASE program
will scan your computer for available addresses.
Line Bias and Termination
Forincreased noise immunity, the communication lines may be loaded at the receiver and biasedat the
transmitter. RS485 communications requires that one transmitter supply abias voltage to ensure a
known "zero" state when all transmitters are off, and the last receiver input at each end of the network
be terminated to prevent "ringing". The ICOM-2S supports these options with jumpers on the card.
See the Option Selection section for more details.

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Auto and Manual Transceiver Control
RS485 communications requires the transmitter driver to be enabled and disabled as needed, to allow
all cards to share the communications line. The ICOM-2S card has two methods to control the driver:
automatic (Auto) and request to send (RTS) control.
With automatic control, the driver is enabled whendata isready to be transmitted. The driver remains
enabled for the transmission time of one character after data transfer is complete. The ICOM-2S
automaticallyadjusts it'stiming tothe baudrate ofthe data. WhenoperatingwithWindowsprograms,
you must use the Auto mode.
With RTS control, your software must set the RTS bit to alogic 1to enable the driver and logic 0to
disable the driver.
Led Monitors
Two LED indicators are provided on the ICOM-2S card. The LEDs blink to indicate activity on the
transmitting and receiving lines and are useful for problem diagnosis. The blinking is more visible at
slower speeds as high speed communication blinks the LEDs too fast for the eye to follow.
Communication Modes
Model ICOM-2S supports Simplex, Half-Duplex, and Full-Duplex communications in avariety of 2
and 4-wire cable connections. Simplex is the simplest form of communications with transmissions
occurring only in one direction. Half-Duplex allows traffic to travel in both directions, but only one
direction at atime. In Full-Duplex mode data travels in both directions at the same time. RS485
communication only supports Half-Duplex because the same pair of signal lines are used for
transmitting and receiving.
CE Marking
If your card is CE-marked unit, it meets requirements of EN50081-1:1992 (Emissions),
EN50082-1:1992 (Immunity), and EN60950:1992 (Safety).

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Specifications
Communications Interface
•Serial Ports: Two shielded male D-sub 9-pin IBM AT style connectors
compatible with RS422 and RS485 specifications. Serial
communications ACE used is type NS16550. Transceivers used
are type 75176.
•Serial Data Rates: 50 to 38,400 baud.(Optionally up to 230,400 baud with change in
clock and opto isolators), Asynchronous, Type 16550 buffered
UART.
•Address: Continuously mappable within 000 to 3FF (hex) range of AT I/O
bus addresses.
•Multipoint: Compatible with RS422 and RS485 specifications. Up to 32
drivers and receivers allowed on line.
•Input Isolation: 500 Volts, from computer and between ports.
•Receiver Input Sensitivity: ±200 mV, differential input.
•Transmitter Output Drive Capability: 60 mA (100 mA short-circuit current capability).
Environmental
•Operating Temperature Range: 0 °C. to +60 °C.
•Storage Temperature Range: -50 °C. to +120 °C.
•Humidity: 5% to 95%, non-condensing.
•Power Required: +5VDC at 150 mA typical, +12 VDC at 200 mA typical., 3 W
total power consumption.
•Size: 10 " long. (3/4 length) Although designed for a full-length slot,
if the card is installed in a eight-bit XT-style slot the card will
work but higher order IRQs 10-15 will be unavailable.)

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Figure 1-1: ICOM-2S Block Diagram
(Only one serial channel shown)

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Chapter 2: Installation
The software provided with this card is contained on either one CD or multiple diskettes and must be
installed onto your hard disk prior to use. To do this, perform the following steps as appropriate for
your software format and operating system. Substitute the appropriate drive letter for your CD-ROM
or disk drive where you see d: or a: respectively in the examples below.
CD Installation
DOS/WIN3.x
1. Place the CD into your CD-ROM drive.
2. Type ???to change the active drive to the CD-ROM drive.
3. Type ????????to run the install program.
4. Follow the on-screen prompts to install the software for this card.
WIN95/98/NT
1. Place the CD into your CD-ROM drive.
2. The CD should automatically run the install program after 30 seconds. If the install program
does not run, click START | RUN and type d:install, click OK or press ?.
3. Follow the on-screen prompts to install the software for this card.
3.5-Inch Diskette Installation
As with any software package, you should make backup copies for everyday use and store your
original master diskettes in asafe location. The easiest way to make abackup copy is to use the DOS
DISKCOPY utility.
In a single-drive system, the command is:
???????????????
You will need to swap disks as requested by the system.
In a two-disk system, the command is:
???????????????
This will copy the contents of the master disk in drive A to the backup disk in drive B.

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To copy the files on the master diskette to your hard disk, perform the following steps.
1. Place the master diskette into a floppy drive.
2. Change the active drive to the drive that has the diskette installed. For example, if the diskette
is in drive A, type ???.
3. Type ????????and follow the on-screen prompts.
Directories Created on the Hard Disk
The installation process will create severaldirectories onyour hard disk. If you accept the installation
defaults, the following structure will exist.
[CARDNAME]
Rootor base directory containing the SETUP.EXE setup program used to helpyou configurejumpers
and calibrate the card.
DOS\PSAMPLES: A subdirectory of [CARDNAME] that contains Pascal samples.
DOS\CSAMPLES: A subdirectory of [CARDNAME] that contains "C" samples.
Win32\language: Subdirectories containing samples for Win95/98 and NT.
WinRisc.exe
AWindows dumb-terminal type communication program designed for RS422/485 operation.
Used primarily with Remote Data Acquisition Pods and our RS422/485 serial communication
product line. Can be used to say hello to an installed modem.
ACCES32
Thisdirectory containsthe Windows95/98/NT driverused toprovide access to the hardwareregisters
when writing 32-bit Windows software. Several samples are provided in a variety of languages to
demonstratehow touse thisdriver. The DLLprovides fourfunctions (InPortB,OutPortB, InPort,and
OutPort) to access the hardware.
This directory also contains the device driver for Windows NT, ACCESNT.SYS. This device driver
provides register-level hardware access in Windows NT. Two methods of using the driver are
available,throughACCES32.DLL(recommended)andthroughtheDeviceIOControlhandlesprovided
by ACCESNT.SYS (slightly faster).

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SAMPLES
Samplesfor usingACCES32.DLL are provided in this directory. Using this DLL not only makes
the hardware programming easier (MUCH easier), but also one source file can be used for both
Windows 95/98 and WindowsNT. One executable can run under both operating systems and still
have full access to the hardware registers. The DLL is used exactly like any other DLL, so it is
compatible with any language capable of using 32-bit DLLs. Consult the manuals provided with
your language's compiler for information on using DLLs in your specific environment.
VBACCES
Thisdirectory contains sixteen-bit DLL drivers for use withVisualBASIC 3.0and Windows3.1 only.
These drivers provide four functions, similar to the ACCES32.DLL. However, this DLL is only
compatible with 16-bit executables. Migration from 16-bit to 32-bit is simplified because of the
similarity between VBACCES and ACCES32.
PCIThis directory contains PCI-bus specific programs and information. If you are not using a PCI card,
this directory will not be installed.
SOURCE
Autility program is provided with source code you can use to determine allocated resources at
run-time from your own programs in DOS.
PCIFind.exe
Autility for DOS and Windows to determine what base addresses and IRQs are allocated to installed
PCI cards. This program runs two versions, depending on the operating system. Windows 95/98/NT
displays aGUI interface, and modifies the registry. When run from DOS or Windows3.x, a text
interface is used. For information about the format of the registry key, consult the card-specific
samples provided with the hardware. In Windows NT, NTioPCI.SYS runs each time the computer
isbooted,therebyrefreshing theregistry asPCI hardwareis addedor removed. InWindows95/98/NT
PCIFind.EXE places itself in the boot-sequence of the OS to refresh the registry on each power-up.
This program also provides some COM configuration when used with PCI COM ports. Specifically,
it will configure compatible COM cards for IRQ sharing and multiple port issues.
WIN32IRQ
This directory provides a generic interface for IRQ handling in Windows 95/98/NT. Source code is
provided for the driver, greatly simplifying the creation of custom drivers for specific needs. Samples
are provided to demonstrate the use of the generic driver. Note that the use of IRQs in near-real-time
data acquisition programs requires multi-threaded application programming techniques and must be
considered an intermediate to advanced programming topic. Delphi, C++ Builder, and Visual C++
samples are provided.

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Findbase.exe
DOS utility to determine an available base address for ISA bus , non-Plug-n-Play cards. Run this
program once, before the hardware is installed in the computer, to determine an available address to
give the card. Once the address has been determined, run the setup program provided with the
hardware to see instructions on setting the address switch and various option selections.
Poly.exe
Ageneric utility to convert atable of data into an nth order polynomial. Useful for calculating
linearization polynomial coefficients for thermocouples and other non-linear sensors.
Risc.bat
A batch file demonstrating the command line parameters of RISCTerm.exe.
RISCTerm.exe
A dumb-terminal type communication program designed for RS422/485 operation. Used primarily
with Remote Data Acquisition Pods and our RS422/485 serial communication product line. Can be
used to say hello to an installed modem. RISCTerm stands for Really Incredibly Simple
Communications TERMinal.
Installing the Card
The ICOM-2S card can be installed in along slot of an IBM PC/XT/AT or compatible computer.
Before carefully read the Option Selection and Address Selection chapters of this manual and
configure the cardaccording to your requirements. You can find an unused base address with the
FINDBASE program provided on the CD that came with your card. Finally, our setup program will
lead you through the process of setting the options on the ICOM-2S. The setup program does not set
the options on the card, these must be set by jumpers on the card.
Be especially careful with address selection. If the addresses of two installed functions overlap you
will experience unpredictable computer behavior.

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To Install the Card
1. Turn off computer power.
2. Remove the computer cover.
3. Remove the blank I/O backplate.
4. Install jumpers for selected options from either the Option Selection of this manual or the
suggestions of our ICOM2SET setup software program.
5. Select the base address on the card for either the Address Selection of this manual or the
suggestions of our FINDBASE setup software program.
6. Install the card in an I/O expansion slot.
7. Install the I/O cable.
8. Inspect for proper fit of the card and cable and tighten screws. Make sure that the card
mounting bracket is properly screwed into place and that there is a positive chassis ground.
9. Turn the computer ON and observe the LED indicators. The LEDs will blink when there is
any activity on the communication lines.
10. Turn the computer OFF and replace the computer cover.
Note
If installed in an eight-bit slot, IRQs 10-15 will be unavailable.
Two DB9 connectors are provided on the mounting bracket for input/output connections. To ensure
that there is minimum susceptibility to EMI and minimum radiation, it is important that the card
mounting bracket be properly screwed into place and that there be a positive chassis ground. Also,
proper EMI cabling techniques (cable connect to chassis ground at the aperture, shielded twisted pair
wiring, etc.) be used for input/output wiring.

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Figure 3-1: Simplified Schematic
Chapter 3: Option Selection
The following paragraphs describe the functions of the various jumpers on the ICOM-2S card. Refer
to the Figure 3-2, Option Selection Map for the locations of these jumpers on the card.
CTS
The CTS bit is used to indicate that the device connected to the ICOM-2S is ready to accept data from
the ICOM-2S. Status can be tested by reading bit 4of the MSR(modem status register) from the
UART. The CTS line does not affect the operation of the card.
Terminations and Bias
Atransmissionlineshouldbeterminatedatthe receivingend inits characteristicimpedance. Installing
ajumper at the location labeled LD applies a136?load across the input for RS422 mode and across
the transmit/receive input/output for RS485 operation. When noise is a potential problem on long
lines, the terminating resistor should be divided and its center point grounded to help reduce noise
voltage pickup. To accomplish this, also install a jumper at the position marked LD GND for 68-ohm
termination resistance on the positive and negative branches of the receiving line.
In RS485 operations, where there are multiple terminals, only the RS485 ports at each end of the
network should have terminating resistors as described above. If the card is to have an ungrounded
load, do as above except do not install the
LDGND jumper. (See Appendix A,
Application Considerations.) Also, for RS485
operation, there must be abias on the RX+ and
RX- lines. If the ICOM-2S card is to provide
that bias, install jumpers at the locations
labeled +BIAS and -BIAS.
RTS Control
ForRS485 operation,installing ajumper atthe
location labeled RTS allows the state of the
RTS line to becontrolled by the UART. Either
this jumper, or the AUTO (A/B) jumper, must
be installed.
Auto (A/B)
Allows the ACE data buffer to automatically
controlthetransmitterdrivers. When operating
with Windows programs, use the Auto mode.

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Simplex or Duplex
The receiver can be set in either Simplex or Duplex by installing jumpers marked SX or DX. Simplex
mode is intended for one-way communication able to transmit or receive. Duplex mode allows
transmission or reception either simultaneous or alternatively as defined in the following paragraph.
Full or Half-Duplex
Full-Duplex allows simultaneous bi-directional communications andis selectedby installing the FDX
jumper. Half-Duplex allows bi-directional transmit and receiver communication but only one at a
time, and is required for RS485 communications. Proper selection depends on the wire connections
used to connect the two serial ports. Tx is the transmit wires and Rx is the receive wires.
Communication Modes and Cabling Options
Cable
Mode Jumpers Card A Card B
Simplex 2-wire Receive Only DX-FDX Rx- 1...........3
Rx+ 9...........2
Simplex 2-wire Transmit Only SX-FDX Tx+ 2...........9
Tx- 3...........1
Half-Duplex 2-wire with local echo DX-HDX-RTS Trx+ 9...........9
Trx- 1...........1
Half-Duplex 2-wire w/o local echo SX-HDX-RTS Trx+ 9...........9
Trx- 1...........1
Full-Duplex 4-wire w/o local echo DX-FDX Tx+ 2...........9
Tx- 3...........1
Rx- 1...........3
Rx+ 9...........2
Interrupts
In addition to standard interrupt levels IRQ2 through IRQ7, the ICOM-2S also supports higher
interrupts IRQ10 through IRQ15 (Except for IRQ13). Select the desired level by installing a jumper
in one of these locations. If the ICOM-2S is installed in a short eight-bit slot, the higher interrupts
IRQ10 through IRQ15 will be unavailable to the card.

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Switches
S1=COM-A Address
S2=COM-B Address
(This illustration has COM Aat the COM 3
address, and COM B at COM 4 address.)
Jumpers
FDX/HDX=Full/Half Duplex
SX/DX=Simplex/Duplex
RTS=Software RTS option
AUTOA, AUTOB=Auto RTS option
BIAS=RS485 Bias Voltage
CTS=Forced CTS signal
LD,LDGND=Transmission Load Jumpers
(See the Option Selection chapter of the
manual or the setup software for
explanations of the above option jumpers)
Connectors
J1=COM-B
J2=COM-A
Figure 3-2: ICOM-2S Option Selection Map

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Chapter 4: Address Selection
The ICOM-2S base address can be selected anywhere within an I/O address range 100-3F8 hex,
providing that the address does not overlap with other functions. If in doubt, refer to the table below
for alist of standard address assignments. (The primary and secondary binary synchronous
communication ports are supported by the Operating System.) The base address locator program
FINDBASEprovided on CD will assist you to select a base address that will avoid conflict with other
installed computer resources.
Hex Range Usage
000-01F DMA Controller 1
020-03F INT Controller 1, Master
040-05F Timer
060-06F 8042 (Keyboard)
070-07F Real Time Clock, NMI Mask
080-09F DMA Page Register
0A0-0BF INT Controller 2
0C0-0DF DMA Controller 2
0F0 Clear Math Coprocessor Busy
0F1 Reset Coprocessor
0F8-0FF Arithmetic Processor
1F0-1F8 IDE Fixed Disk
200-207 Game I/O
278-27F Parallel Printer Port 2
2F8-2FF Asynchronous Comm’n (Secondary)
300-31F Prototype Card
360-36F Reserved
378-37F Parallel Printer Port 1
380-38F SDLC or Binary Synchronous Comm’n 2
3A0-3AF Binary Synchronous Comm’n 1
3B0-3BF Monochrome Display/Printer
3C0-3CE Local Area Network
3D0-3DF Color/Graphic Monitor
3F0-3F7 Floppy Diskette Controller
3F8-3FF Asynchronous Comm’n (Primary)
Table 4-1: Standard Address Assignments for 286/386/486 Computers

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I/Obus addressswitches aremarked A3-A9. The following table lists switch label vs. the address line
controlled and the relative weights of each.
Address Switch Settings 1st Digit 2nd Digit 3rd Digit
Switch Label 765432 1
Address Line Controlled A9 A8 A7 A6 A5 A4 A3
Decimal Weight 512 256 128 64 32 16 8
Hexadecimal Weight 200 100 80 40 20 10 8
Table 4-2: ICOM-2S Address Switch Setup
In order to read the address switch setup, assign abinary "1" to switches that are turned OFF and a
binary "0" to switches in the ON position. For example, as illustrated in the following table, switch
selection corresponds to binary 10 1101 1xxx (hex 2D8). The "xxx" represents address lines A2, A1,
and A0 used on the card to select individual registers. See Chapter 5, Programming of this manual.
Switch Label A9 A8 A7 A6 A5 A4 A3
Setup OFF ON OFF OFF ON OFF OFF
Binary Representation 1 0 1 1 0 1 1
Conversion Factors 2 1 8 4 2 1 8
HEX Representation 2D8
Table 4-3: Example Address Setup
Review the Address Selection Table carefully before selecting the card address. If the addresses of
two installed functions overlap you will experience unpredictable computer behavior.