AXIOMTEK AX10445 Series User manual

AX10445 Series
Isolated Dual Channel RS422/485
Interface Module
User’s Manual

ii
Disclaimers
The information in this manual has been carefully checked and is
believed to be accurate. AXIOMTEK Co., Ltd. assumes no
responsibility for any infringements of patents or other rights of third
parties which may result from its use.
AXIOMTEK assumes no responsibility for any inaccuracies that may
be contained in this document. AXIOMTEK makes no commitment to
update or to keep current the information contained in this manual.
AXIOMTEK reserves the right to make improvements to this document
and/or product at any time and without notice.
No part of this document may be reproduced, stored in a retrieval
system, or transmitted, in any form or by any means, electronic,
mechanical, photocopying, recording, or otherwise, without the prior
written permission of AXIOMTEK Co., Ltd.
 Copyright 1999 by AXIOMTEK Co., Ltd.
All rights reserved.
November 1999, Version A2
Printed in Taiwan

iii
ESD Precautions
Integrated circuits on computer boards are sensitive to static
electricity. To avoid damaging chips from electrostatic
discharge, observe the following precautions:
nDo not remove boards or integrated circuits from their anti-static
packaging until you are ready to install them.
nBefore handling a board or integrated circuit, touch an unpainted
portion of the system unit chassis for a few seconds. This helps to
discharge any static electricity on your body.
nWear a wrist-grounding strap, available from most electronic
component stores, when handling boards and components.
Unpacking
After unpacking the CPU card, check and see if the following
items are included and in good condition. If any of the items
is missing or damaged, notify your dealer immediately.
The AX10445A/A+ Isolated Dual Channel RS422/485 Interface
Module package includes the following:
nAX10445A or AX10445A+ Board
nScrew 3mm (x4)
nBronze standoffs 6mm (x4)
nAS59099 DAC Driver CD
The AX10445B/B+ Isolated Dual Channel RS422/485 Interface
Module package includes the following:
nAX10445B or AX10445B+ Board
nScrew 3mm (x4)
nBronze standoffs 6mm (x4)
nAS59099 DAC Driver CD
Make sure that all of the items listed above are present.

iv
What To Do If There Is A Problem
If there are damaged or missing parts, contact your supplier
and/or dealer immediately. Do not attempt to apply power to
the board if there is damage to any of its components.
Trademarks Acknowledgments
AXIOMTEK is a trademark of AXIOMTEK Co., Ltd.
IBM is a registered trademark of International Business
Machines Corporation.
MS-DOS, Microsoft C and QuickBasic are trademarks of
Microsoft Corporation.
TURBO C is a trademark of Borland Inc.
BASIC is a trademark of Dartmouth College.
Intel is a trademark of Intel Corporation.
Other brand names and trademarks are the properties and
registered brands of their respective owners.

Table of Contents
v
T a b l e o f C o n t e n t s
Chapter 1 Introduction
1.1 General Description .........................................1
1.2 Features..........................................................2
1.3 Specifications..................................................3
Chapter 2 Setting up the AX10445
2.1 Installing the AX10445 ......................................5
2.2 DIP Switches (Base Address Selection) ..............6
2.3 Jumper Settings...............................................7
2.3.1 JP9 (IRQ Level Selection)...................................7
2.3.2 JP5, JP8 (RS422/485 mode selection) ...............8
2.3.3 JP1 & JP2, JP3 & JP4 (Bypass protection
resistors).........................................................................8
2.3.4 JP6 & JP7 (Enable/Disable)................................9
2.4 Pin Assignments............................................. 10
2.5 Signal Wirings............................................... 12
Chapter 3 Technical Reference
3.1 UART Register Description .............................. 13
3.2 About EIA RS-422/485...................................... 17
3.3 Driver and Receiver Circuit............................. 19
3.3.1 Driver Detail......................................................19
3.3.2 Receiver Detail.................................................19
3.4 Isolation Circuit (for AX10445A) ....................... 20
3.5 Termination Resistor ...................................... 20
3.6 Surge Absorber..............................................xx
20

Table of Contents
vi
Chapter 4 Application
4.1 General......................................................... 21
4.2 Demo Program for QB4.5.................................22
4.3 Demo Program for Turbo Pascal...................... 24
4.4 Demo Program for TC for User to Communicate
with Remote Device........................................ 27
Appendix A AX10445A Location Diagram
Appendix B AX10445B Location Diagram
Appendix C Block Diagram
Appendix D PC I/O Address Map
Appendix E PC IRQ Map
Appendix F PC/104 Mechanical
Specifications
General Description ................................................ 45
Module Dimensions................................................. 45

AX10445 Module Series User’s Manual
Introduction 1
C h a p t e r 1
Introduction
1.1 General Description
The AX10445, a dual channel asynchronous serial
communication with two RS-422/485 serial interfaces, is a
PC/104 form-factor universal PC/104 bus module that plugs
directly into PC/104 carrier module. The AX10445 Series
permits higher data rates and longer cable lengths of
asynchronous communications than RS-232 do. Complete
with this AX10445, your PC can communicate with other
computers or devices having the same communication
parameters and interface (through the two 9-pin D-type
connectors on the right edge of this module). For protection
against electrical surges, at both channels, there are onboard
varistors connected between each of the differential
communication wire lines.

AX10445 Module Series User’s Manual
Introduction
2
You could fully integrate your PC with the AX10445 Series by
simply plugging it in a PC/104 expansion bus. If the two
standard serial ports (COM1 and COM2) are used, then no
certain control code will be needed for AX10445.
RS-422 and RS-485 use differential signal lines that decrease
noise effect in data transmission. RS-422 is a unipolarity
differential protocol good to 10M baud and to 4000 feet. RS-
485 is similar to RS-422, but with additional specifications so
that many drivers and receivers can share a single line. Thus,
the feature of RS-422 is one driver to multiple receivers while
RS-485’s is several drivers to multiple receivers’multi-drop
communication.
You may assign your board to either RS-422 or RS-485 type
of transmission via JP5. Please refer to Chapter 2 for the
proper jumper settings.
1.2 Features
lTwo independent EIA RS-422/485 interface
lReliable communication up to 4000 feet (1.2KM)
at 100K bps
lIBM compatible serial ports up to 56000 BAUD
rates
lSelectable UART port address from hex 200 to
3F8
lJumper selectable interrupt level IRQ 3, 4, 5, 7,
10, 11, 12
lSupports TX, RX, RTS and CTS signals
lTwo or four wire operation
lRS-485 transmitter enable jumper operations:
always enable and RTS enable
lOnboard termination resistors space
lOnboard surge absorbers space
lFully isolated input and output for AX10445A
lOnboard TX, RX LED indicators

AX10445 Module Series User’s Manual
Introduction 3
1.3 Specifications
lDimension: 95mm (3.74inch) X 90mm
lBaud rate: 50 –56,000bps
lClock input: 1.8432MHz
lInterrupt level: IRQ 3, 4, 5, 7, 10, 11, 12
lI/O connection: Dual 9-pin D type male
connectors
lTransmitter:
nDevice: SN75172 or equivalent
nHigh level voltage: 3.7V typical at 33mA source
nLow level voltage: 1.1V typical at 33mA source
nHigh level current: 60mA source max
nLow level current: 60mA sink max
lReceiver:
nDevice: SN75173 or equivalent
nDifferential input threshold:0.2V max
nHysteresis: 50mA typical
nInput impedance: >12K Ohm with out terminators
lPower Consumption:
n+5V, 500mA typical for AX10445A
n300mA typical for AX10445B

AX10445 Module Series User’s Manual
4
This page does not contain any information.

AX10445 Module Series User’s Manual
Setting up the AX10445 5
C h a p t e r 2
Setting up the AX10445
WARNING Before connecting or disconnecting any
cable on the AX10445 module series, you
should always TURN OFF the PC.
Here are some things you must make sure before installing
the AX10445 module series:
1. It is not allowed to have two cards or more with the
same I/O port base address.
2. Disable both of your CPU’s RS-232 serial interfaces, if
there are any.
3. Determine your desired communication type, RS-422 or
RS-485. Make sure that you are using the correct cable
connection as it different for RS-422 and RS-485. See
Section 2.5 Signal Wirings.
2.1 Installing the AX10445
Now you may begin with the installation:
1. Turn off the system power.
2. Unplug all power cords.
3. Remove the case cover if necessary.
4. Remove the top module if it is a non-stackthrough
module.
5. Put the AX10445 module in line with the present
module as described in Appendix F.
6. Connect the cable if necessary (CH#1: J1/J3, CH#2:
J2/J4).
7. Press the modules against each other until the gap
between modules is equivalent to the Spacer’s height
(0.6”). Restore all the screws.
8. Repeat step 6 until all modules are set into position.
9. Turn on the system power.

AX10445 Module Series User’s Manual
Setting up the AX10445
6
2.2 DIP Switches (Base Address
Selection)
The AX10445 interface module is controlled through the I/O
port. The I/O port base addresses are selected via DIP
switches. To help you locate the DIP switches (on this board
there are two DIP switches for Channel #1 and Channel #2
respectively), refer to the location diagram in Appendix A
and Appendix B.
The valid I/O port base addresses range from hex 200 to hex
3F8. Within this range you may specify your base addresses.
However it is not allowed to have two or more devices with
the same base address. Usually the I/O port base address is
set to the standard serial communication port COM1 (3F8 –
3FF) and COM2 (2F8 –2FF). The following table illustrates
the base addresses and corresponding switch settings.
1 2 3 4 5 6
SW2
O
N
DIP Switch
A8
A7
A6
A5
A4
A3
CH#1
COM1
1 2 3 4 5 6
SW1
O
N
DIP Switch
A8
A7
A6
A5
A4
A3
CH#2
COM2
* A9 is always set at "1"

AX10445 Module Series User’s Manual
Setting up the AX10445 7
Base Address
A8 A7 A6 A5 A4 A3 Connect
200 –207 ON ON ON ON ON ON
208 –20F
.
.
ON ON ON ON ON OFF
2E8 –2EF ON OFF OFF OFF ON OFF COM4
2F0 –2F7 ON OFF OFF OFF OFF ON
2F8 –2FF
.
.
ON OFF OFF OFF OFF OFF COM2*2
3E8 –3EF OFF OFF OFF OFF ON OFF COM3
3F0 –3F7 OFF OFF OFF OFF OFF ON
3F8 –3FF OFF OFF OFF OFF OFF OFF COM1*1
NOTE: 1. factory setting for channel 1
2. factory setting for channel 2
2.3 Jumper Settings
Simply lift off the jumper’s cap and place it on the
appropriate pair of pins (to activate/enable) or put it over the
pin (to deactivate/disable). The location diagram in Appendix
Aand Appendix B will assist you in locating these jumpers.
2.3.1 JP9 (IRQ Level Selection)
JP9 selects the IRQ level (Interrupt Request), numbered from
3 through 12. The CH#1 IRQ select is located on the upper
pin row, whereas CH#2 is located at the lower pin row
position. For instance, if the I/O port of Channel #1 is set to
Hex 3F8 (COM1) and Channel #2 to Hex 2F8 (COM2) then the
jumper JP9 must be selected respectively. See the setting of
JP9 on Figure 1.
WARNING: The IRQ number for each channel must not
be the same.

AX10445 Module Series User’s Manual
Setting up the AX10445
8
10 11 12 7543
CH #1 (COM1)
CH #2 (COM2)
IRQ
JP9
Figure 1 Factory Setting of JP9
WARNING: Refer to Appendix E for the IRQ Map.
2.3.2 JP5, JP8 (RS422/485 mode selection)
The AX10445 module series supports two types of data
transmissions: RS422 and RS485. For CH#1 you may assign
AX10445 to either one of them, just set JP5 according to
description below: (CH#2 be defined at JP8).
123
485 422
(RS422 Mode)
or 123
485 422
(RS485 Mode)
Figure 2 RS422/485 Mode Selection
When the jumper is at 485 position, this transmit driver is
controlled by RTS signal. When using RS485 mode, the
software must provide this RTS enable/disable ability.
If the software package does not support RTS enable/disable
ability, then you have to find another way to resolve it.
Please continue reading onto the next section.
2.3.3 JP1 & JP2, JP3 & JP4 (Bypass protection
resistors)
Mounting the jumper caps on JP1/JP2 (for CH#1) sends the
driver signal straight out without passing through any
resistors (R7 and R8). JP3 and JP4 are similar to JP1 and
JP2 except that the pair of JP3/JP4 serves CH#2.

AX10445 Module Series User’s Manual
Setting up the AX10445 9
In some circumstances, you need RS-422 mode of AX10445
connected to some other system using RS-485 transmission
network. In such cases, it is necessary to take off these
jumper’s caps.
2.3.4 JP6 & JP7 (Enable/Disable)
The AX10445 Series supports enable/disable module
operation.
When JP7 (JP6) is set as Short 1-2 position, CH#1 (CH#2) is
enabled for use.
Setting as Short 2-3 position disables CH#1 (CH#2).
or
1 2 3
(Enable)
123
(Disable)

AX10445 Module Series User’s Manual
Setting up the AX10445
10
2.4 Pin Assignments
Electrical signal assignments for the two 9-pin D-type or two
10-pin pin header connectors are described in this section.
6
7
8
9
1
2
3
4
5
RTS-
RTS+
CTS+
CTS-
TX-
TX+
RX+
RX-
GND
9-pin D type
TX -
GND
RX -
RX+
TX+
1
9
7
5
32
10
8
6
4RTS -
GND
CTS -
CTS +
RTS+
10-pin pin header
Pin on Connector Abbreviation Signal
1TX-Transmit Data -
2TX+ Transmit Data +
3RX+ Receive Data +
4RX-Receive Data -
5GND Ground
6RTS-Request to Send -
7RTS+ Request to Send +
8CTS+ Clear to Send +
9CTS-Clear to Send -

AX10445 Module Series User’s Manual
Setting up the AX10445 11
Control signals such as RTS and CTS are used to coordinate
the transmission and reception of data, and the term
handshaking is used to describe it. A brief description of the
functional characteristics of each signal line follows:
1. Transmit
Data :The DTE uses this line to transmit data to other DTE.
2. Receive
Data :Data are received from other DTE via this line.
3. Ground :This line establishes a common ground reference for all
signal lines.
4. Request to
Send :When active, this line conditions the receptor DTE for
data transmission. In the case of full duplex
communication it may be kept constantly active to
maintain the receptor in transmit mode. In half duplex
communication, RTS must be inactive while in receive
mode.
5. Clear to
Send :The receptor DTE activates this line to indicate its
readiness for data transmission. It does so after the
transmitter DTE activates RTS.

AX10445 Module Series User’s Manual
Setting up the AX10445
12
2.5 Signal Wirings
RS-422 and RS-485 are new standards intended to succeed
the popular RS-232. RS-422 and RS-485 still preserve most
of the signals specified in RS-232. However the signal wirings
are different. The RS-422 interface is based on one-to-one
principles, while the RS-485 interface is based on wire
sharing.
For the RS-422 interface, the cable must follow the
connection description below:
TX- 1
TX+ 2
RX+ 3
RX- 4
GND 5
RTS- 6
RTS+ 7
CTS+ 8
CTS- 9
DTE 1
4 RX-
3 RX+
2 TX+
1 TX-
5 GND
9 CTS-
8 CTS+
7 RTS+
6 RTS-
DTE2
For the RS-485 (two-wire mode) interface, the connection
description is as follows: (twisted wire drawings omitted)

AX10445 Module Series User’s Manual
Setting up the AX10445 13
1 TX-, 4 RX-
2 TX+, 3 RX+
5 GND
DTE 1
1 TX-, 4 RX-
2 TX+, 3 RX+
5 GND
DTE 2
1 TX-, 4 RX-
2 TX+, 3 RX+
5 GND
DTE 32
For the RS-485 (four-wire mode) interface, the connection
description is as follows: (twisted wire drawings omitted)
1 TX-
2 TX+
3 RX+
4 RX-
5 GND
MASTER
(422/485)
(485 TYPE)
S
L
A
V
E
1
1
T
X
-
2
T
X
+
3
R
X
+
4
R
X
-
5
G
N
D
(485 TYPE)
S
L
A
V
E
32
1
T
X
-
2
T
X
+
3
R
X
+
4
R
X
-
5
G
N
D
NOTE:Please use twisted wires or flat cables for
connections.

AX10445 Module Series User’s Manual
Setting up the AX10445
14
This page does not contain any information.