PC247H2-8H2 Series

Page 1

Amplicon products are designed and manufactured in the United Kingdom under a quality system approved by the British Standards In stitution

PC247H2-8H2 SERIES

DUAL CHANNEL SERIAL

COMMUNICATIONS BOARD

WITH ISOLATION OPTION

This Instruction Manual is supplied with the PC247H2 and the PC 248H2 Serial Data Communications Board to provide the user with sufficient information to utilise the product in a proper and efficient manner. The information contained has

been reviewed and is believed to be accurate and reliable, however Amplicon Liveline Limited accepts no responsibility for any problems caused by errors or omissions. Specifications and instructions are subject to change

without notice.

PC247H2-8H2 Series Instruction Manual Part Nº 859 864 44 Issue B3

© Amplicon Liveline Limited

Prepared by D. Cooper and P. Adams

PC247H2-8H2 Series

Page 2

DECLARATION OF CONFORMITY

AMPLICON LIVELINE LIMITED CENTENARY INDUSTRIAL ESTATE

HOLLINGDEAN ROAD BRIGHTON BN2 4AW UK

We declare that the product(s) described in this Instruction Manual are manufactured by Amplicon Liveline Limited and perform in conformity with the following standards or standardisation documents:

EMC Directive 89/336/EEC LVD Directive 73/23/EEC CE Directive 93/68/EEC

Jim Hicks, I. Eng, FIEIE Managing Director

Amplicon Liveline Limited

PC247H2-8H2 Series

Page 3

PC247/8H2 Series Dual Channel Serial Communications Boards w ith Optional Isolation

LIST OF CONTENTS PARA SUBJECT PAGE

1 INTRODUCTION 1 1.1 The Amplicon 200 Series 1 1.2 The Products Described in this Manual 1 1.3 Features of the PC247H2-8H2 Series of Data Communications Boards 1 1.4 General Description 2 1.4.1 Enhanced Features 3 1.5 What the Package Contains 4 1.6 The Amplicon Warranty Covering the PC247H2-8H2 series of Boards 4 1.7 Contacting Amplicon Liveline Limited for Technical Support or Service 4 1.7.1 Technical Support 5 1.7.2 Repairs 5

2 GETTING STARTED 6 2.1 General Information 6 2.2 Installing the Board 6 2.3 Host Computer Requirements 7 2.4 Configuration Switch and Jumper Settings 7 2.4.1 Base Address Selection 7 2.4.2 Interrupt Level Selection (IRQ) 9 2.4.3 RS-485 Full Duplex / Half Duplex Operation 12 2.4.4 Transmission Line Termination 13 2.4.5 Data Rate Range selection 14 2.4.6 Switch and Jumper Factory Settings Summary 14 2.5 Software Installation 15 2.5.1 Software extraction from the Softman 15 2.5.2 Windows 95 & 98 Software Installation 15 2.5.3 Windows 95 & 98 Configuring COM Ports 18 2.5.4 Windows NT Software installation 19 2.5.5 Windows NT Configuring COM ports 19 2.5.6 Windows 2000 Installation 19 2.5.7 Windows 2000 Configuring COM Ports 20 2.5.9 Linux Installation 21 2.6 Installation Testing 21

3 MAKING THE CONNECTIONS 22 3.1 External Connections 22 3.2 RS-232 9 way Port 22 3.3 RS-422/485 9 way Port 22 3.3.1 RS-422/485 9 way Port Amplicon pin assignment 23 3.3.2 RS-422/485 9 way Port Alternative pin assignment 23 3.4 Input/Output Connector Locations 24 3.5 Connector Wiring for RS-422/485 Full/Half Duplex 25 3.5.1 Choice of Cable 25 3.6 The Ground Connections 26 3.6.1 Ground Connections for Non-isolated Boards 26 3.6.2 Ground Connections for Isolated Boards 26

4 USING THE SERIAL COMMUNICATIONS BOARDS 28 4.1 Why Isolate? 28

PC247H2-8H2 Series

Page 4

4.2 Application Notes 30 4.2.1 Applicable Standards 30 4.2.2 RS-232 Application Notes 30 4.3 RS-422/485 Application Notes 31 4.3.1 RS-422/485 Parameters 31 4.3.2 RS-422/485 Signalling Sense 32 4.3.3 RS-422/485 Multi-drop Applications 32 4.3.4 RS-422/485 Bus Termination 33 4.4 Testing and Troubleshooting 34 4.4.1 Testing with the Application Software 34 4.4.2 Testing Using the Supplied Software 35 4.4.3 Loop-back Testing Using A Terminal Emulator 38

5 PROGRAMMING 39 5.1 Programming with Windows NT & 95 Device drivers. 39 5.1.1 Half Duplex Transmission Turnaround 39 5.2 User Programming 40 5.2.1 Programming the UART 40 5.2.2 FIFO Interrupt Mode Operation 40 5.2.3 FIFO Polled Mode Operation 41 5.2.4 Interrupt Operations 41 5.2.5 Non-shared Interrupts 41 5.2.6 Shared Interrupts 42 5.2.7 Half Duplex Transmission Turnaround 43

Appendix A TECHNICAL SPECIFICATIONS 45 APP A1 HARDWARE SPECIFICATION 45 APP A1.1 Function 45 APP A1.2 RS-232 Port 45 APP A1.3 RS-422/485 Port 47 APP A1.4 Modes 48 APP A1.5 UARTS 49 APP A1.6 Interrupts 49 APP A1.7 Power-up Default 50 APP A1.8 PC Interface 50 APP A2 SOFTWARE 51 APP A3 ENVIRONMENTAL CONDITIONS 52 APP A3.1 Environment 52 APP A3.2 Specific conditions 52 APP A3.3 Electro Magnetic Compatibility 52

Appendix B LAYOUT and CIRCUIT Diagrams 53 APP B1 Layout Diagrams 53 APP B2 PC247H2(i) Circuit and Layout Diagrams 55 APP B3 PC248H2(i) Circuit and Layout Diagrams 56 APP B4 Circuit Diagram PC247H2-8H2(i) - All Versions 57 APP B5 USER’S NOTES - DRAWINGS 58

PC247H2-8H2 Series

Page 5

LIST OF FIGURES

FIGURE TITLE PAGE FIGURE 2.1 SWITCH SELECTION OF CHANNEL BASE ADDRESSES 8 FIGURE 2.2 PC I/O MAP ASSIGNMENTS 9 FIGURE 2.3 COM1 TO COM8 ALLOCATIONS 9 FIGURE 2.4 SWITCH SELECTION OF INTERRUPT LEVELS 10 FIGURE 2.5 INTERRUPT LEVEL SWITCH CODES 10 FIGURE 2.6 INTERRUPT LEVEL ASSIGNMENTS 12 FIGURE 2.7 JUMPER SETTING FOR FULL/HALF DUPLEX 13 FIGURE 2.8 JUMPER SETTING FOR ECHO 13 FIGURE 2.9 FACTORY JUMPER SETTING SUMMARY 14 FIGURE 3.1 RS-232 9 WAY PORT PIN DESIGNATIONS 22 FIGURE 3.2 RS-422/485 AMPLICON STANDARD PORT PIN DESIGNATIONS 23 FIGURE 3.3 RS-422/485 ALTERNATIVE STANDARD PORT PIN DESIGNATIONS 23 FIGURE 3.4 INPUT/OUTPUT CONNECTOR LOCATIONS FOR ALL BOARD TYPES 24 FIGURE 3.5 CONNECTIONS FOR FULL AND HALF DUPLEX OPERATION 25 FIGURE 3.6 9 PIN ISOLATED RS-232 CONNECTIONS TO ANOTHER DTE DEVICE 27 FIGURE 4.1 ELIMINATION OF INTERFERING SIGNALS BY ISOLATION 29 FIGURE 4.2 COMMUNICATIONS STANDARDS SUMMARY 32 FIGURE 4.3 RS-422 CONNECTED IN BROADCAST MODE 33 FIGURE 4.4 RS-485 CONNECTED IN MULTI-DROP, HALF DUPLEX MODE 33 FIGURE 4.5 RS-232 9 WAY LOOP-BACK TEST CONNECTIONS 36 FIGURE 4.6 RS-422/485 LOOP-BACK TEST CONNECTIONS 36 FIGURE B.1 PC247H2I LAYOUT DIAGRAM 55 FIGURE B.2 PC248H2I LAYOUT DIAGRAM 56 FIGURE B.3 PC247H2-8H2 CIRCUIT SCHEMATIC PC INTERFACE AND UARTS 60 FIGURE B.4 PC247H2(I) CIRCUIT SCHEMATIC DUAL CHANNEL RS-232 I/O 60 FIGURE B.5 PC248H2(I) CIRCUIT SCHEMATIC DUAL CHANNEL RS-422/485 I/O 61

PC247H2-8H2 Series

Page 1

PC247H2-8H2 Series Dual Channel Serial Communications Boards w ith Isolation Option

1 INTRODUCTION

1.1 The Amplicon 200 Series The Amplicon 200 Series of Personal Computer based data acquisition, control and communication products provides very high performance, affordable hardware with user sympathetic software. The 200 Series is designed for users requiring fast or complex data input/output to the host PC and comprises a range of boards and software to handle most analog and digital signal types. When a large scale system is required, multiple boards can be added from the 200 Series without conflict. In many cases the capacity of the PC mounted hardware can be extended by external expansion and termination panels, which together with the applicable cables, provide a convenient to use system with low cost per channel and maintained high performance.

1.2 The Products Described in this Manual The PC247H2-8H2 Series of communications products includes four variants of dual channel boards with supporting software and accessories. The boards share common circuits and features, and are generically cited in this manual as the PC247H2-8H2 Series. Where a specific board type, or pair, is referenced, nomenclature as in the following examples is used:-

PC247H2-8H2 Series Refers to all boards in the series PC247H2 Refers to the PC247H2 (Dual channel RS-232) PC248H2 Refers to the PC248H2 (Dual Channel RS-422/485 without isolation) PC247/PC248H2(i) Refers to the PC247H2 and/or the PC248H2 with or without isolation

1.3 Features of the PC247H 2-8H2 Series of Data Communications Boards Each of the PC247H2-8H2 Series of boards is designed to meet stringent performance requirements and ease of use while maintaining compatibility with earlier serial communications boards.

• Three point isolated serial communications • Two separate, independent serial ports • Industry standard panel mounted connectors • Flexible, independent addressing • Multiple, selectable IRQ levels • Shared interrupt capability • Mixed modes. RS-232, RS-422, RS-485, 9 way ports • Full Duplex, Half Duplex, Multi-drop applications • RS-485 transmitter enabled automatically in Special Half Duplex mode • FIFO mode provides input and output data buffers for up to 128 characters • Data rates selectable up to 1 MBaud • Full specification signal levels • Implementation of all RS-232 primary control lines • Low power consumption

PC247H2-8H2 Series

Page 2

1.4 General Description The PC247H2-8H2 Series of plug-in boards provides a flexible range of serial communications interfaces for the IBM PC and compatible computers. They are enhanced versions of the Amplicon PC247-9 series. While remaining compatible with the previous designs, the H2 Series offer a number of performance advantages. When used with the enhanced Windows 95, 98, ME, NT, 2000, XP, and Linux drivers supplied, the H2 Series offer increased data rates and improved data buffering with a larger FIFO. The RS-485 ports have a Special Half Duplex mode that causes the transmit buffer to be enabled automatically, by the UART, whenever data is waiting to be sent from the UART Transmit buffer. All models are supported by enhanced Windows 95, 98, ME, NT, 2000, XP, and Linux drivers. These drivers are a superset of the Microsoft serial drivers and allow the boards to operate as standard serial ports. These drivers also allow the advanced features of the boards to be fully utilised by the application software. The Windows 95 driver is also compatible with Windows 98 and the Windows 2000 driver is also compatible with Windows XP. The PC247H2I and the PC248H2I are designed to isolate the serial communications from the computer power. The design is such that it will sustain common mode voltages up to 75Vdc, which is outside of the low voltage directive (73/23/EEC). However in fault conditions they are protected to sustain common mode voltages up to peaks of 250Vdc. Six models are available in the range, three of which provide isolation of the data and control lines. The PC247H2I and the PC248H2i boards with isolated input/output circuits will be used in serial communications systems where high integrity data transmission and reception are required in an electrically severe environment. Each board is half length and supports two independent serial ports designed to meet a combination of the following standards:

RS-232 full or half duplex serial port furnished with a 9 pin D-type male connector conforming to IBM practice. The port is fully configured with two data and five control I/O lines. RS-485 full duplex, half duplex, multi-drop operation or RS-422 full duplex with or without RTS-CTS control lines. Depending on the application, RS-485 or RS-422 operation is selected by making the appropriate connections. Each RS-422 / 485 port is furnished with a 9 pin D-type male connector.

For conformance with the latest RS-422/485 standard specifications, the nomenclature of the data lines is amended. The RS-422/485 levels and polarities remain unchanged and the actual external data bus wiring needs no changes.

Serial input/output facilities of the series comprise:

PC247H2 Provides two independent 9 pin RS-232 ports, one on each of the upper (port 1) and lower (port 2) channels

PC248H2 Provides two independent RS-422/485 ports, one on each of the upper

(port 1) and lower (port 2) channels PC247H2i Provides two independent separately isolated 9 pin RS-232 ports, one on

each of the upper (port 1) and lower (port 2) channels PC248H2i Provides two independent isolated RS-422/485 ports, one on each of

the upper (port 1) and lower (port 2) channels

PC247H2-8H2 Series

Page 3

Communications parameters of both ports of all versions are fully programmable for compatibility with other devices connected to the interface and to allow set up by the communications program.

1.4.1 Enhanced Features

The PC247H2-8H2 series all support two data rate ranges. One compatible with the previous PC247-9 series and the other supports increased data rates up to 1 MBaud when using the enhanced Windows 95, 98, ME, NT, 2000, XP, or Linux drivers supplied. Selection between these ranges is by means of a jumper link. The previous PC247-9 series supported FIFOs up to 16 characters deep, allowing data to be read from and written to the serial port in bursts, easing application layer programming timing restrictions. When used with the enhanced Windows 95, 98, ME, NT, 2000, XP, or Linux drivers supplied, the range supports the transmit and receive FIFO size up to 128 characters. In many cases this will give vast performance advantages allowing the processor much more time between serial port services. The PC247H2-8H2 range have another useful advantage if you have an RS-485 Half Duplex or Multidrop Application. This is Special Half Duplex mode. In this mode the RS-485 transmit buffer is enabled automatically by the UART whenever data is waiting to be sent in the UART Transmit buffer. This useful feature makes efficient multidrop communication simple to implement by removing the burden of the Transmit buffer enable control from the software. Special Half Duplex mode requires the use of the enhanced Windows 95, 98, ME, NT, 2000, XP, or Linux drivers driver supplied. Selection of this mode is by means of jumper links and device driver options. The enhanced Windows 95, 98, ME, NT, 2000, XP, and Linux drivers allow the choice of any standard baud to be selected from the control panel. However any baud can be selected when programming from high level languages that support communication to serial com ports, by simply entering the baud in the normal 'baud rate' call.

PC247H2-8H2 Series

Page 4

1.5 What the Package Contains

! CAUTION

Some of the components on the board are susceptible to electrostatic discharge, and proper handling precautions should be observed. As a minimum, an earthed wrist strap must be worn when handling the PC247H2-8H2 Series board outside its protective bag. Full static handling procedures are defined in British Standards Publication BSEN100015/BSEN100015-1:1992 When removed from the bag, inspect the board for any obvious signs of damage and notify Amplicon if such damage is apparent. Do not plug a damaged board into the host computer. Keep the protective bag for possible future use in transporting the board.

The package as delivered from Amplicon Liveline Ltd contains:-

1. The plug-in board as ordered, in a protective bag. The model will be one of the following,

and is identified by the type number printed on the board.

PC247H2 Dual RS-232 Serial Communications Controller

PC248H2 Dual RS-422/485 Serial Communications Controller

PC247H2i Dual RS-232 Serial Communications Controller with I/O signal isolation

PC248H2i Dual RS-422/485 Serial Communications Controller with I/O signal isolation

2. SoftMan CD for your Manual and Software . Part Nº 86986559 3. Any additional accessories (mating connectors, software etc.) may be packed separately.

1.6 The Amplicon Warranty Covering the PC247H 2-8H2 series of Boards

This product is covered by the warranty as detailed in the Terms and Conditions stated in the current domestic or international Amplicon Liveline catalogue.

1.7 Contacting Amplicon Liveline Limited for Techni cal Support or Service

The PC247H2-8H2 Series boards are designed and manufactured by Amplicon Liveline Ltd and maintenance is available throughout the supported life of the product.

PC247H2-8H2 Series

Page 5

1.7.1 Technical Support Should the board appear defective, please check the information in this manual and any 'Help' or 'READ.ME' files appropriate to the program in use to ensure that the product is being correctly applied. If an application problem persists, please request Technical Support on one of the following numbers:

Web: www.amplicon.com Internet: support@amplicon.com Telephone: UK 01273 944 835 Calls cost 5p a min from a BT landline. Calls from other services may vary. Fax: UK 01273 570 215

It will assist the support engineer if you have the following information available when you call:

Date of purchase Your postcode The Operating System you are running under The specification of your computer The nature of your problem and the results of any tests you have conducted.

You will also be asked if the operating system prompted you for a disk the first time you powered up your computer after insertion of the board.

1.7.2 Repairs If the board requires repair then please return the goods enclosing a repair order detailing the nature of the fault. If the board is still under warranty, there will be no repair charge. For traceability when processing returned goods, a Returned Materials Authorisation (RMA) procedure is in operation. Before returning the goods, please request an individual RMA number by contacting Amplicon Customer Services by telephone or fax on the above numbers. Please mark the RMA number on the outside of the packaging to ensure that the package is accepted by the Goods Inwards Department. Give the reason for the return and, if the goods are still under warranty, the original invoice number and date. Repair turnaround time is normally five working days but the Service Engineers will always try to co-operate if there is a particular problem of time pressure. Address repairs to: Customer Services Department AMPLICON LIVELINE LIMITED Centenary Industrial Estate Brighton, East Sussex BN2 4AW England

PC247H2-8H2 Series

Page 6

2 GETTING STARTED 2.1 General Information

Each board from the PC247H2-8H2 Series is factory configured so that it may be installed in a suitable host PC (see paragraphs 2.2 and 2.3), and allow execution of normal serial communications programs, or the supplied loop-back test program. To use the PC247H2-8H2 Series board in RS-485 half-duplex programs or systems prepared for the earlier PC47AT, PC48AT or PC49AT, check the following points:

Transmission turn-around in half duplex operation is now controlled by RTS (Bit 1 of the Modem Control Register) instead of /OUT1 (Previously bit 2 of the Modem Control Register). This transmission turnaround feature is not normally used in standard communications programs, but may have been implemented in bespoke software. The external two-wire connection for half duplex operation needs to be linked to both Rx and Tx pin pairs of the 9 way connector. (See Figure 3.5)

2.2 Installing the Board

Depending on other adapters that may be installed in the host PC or on the requirements of the user, hardware configuration may be necessary before installing the PC247H2-8H2 Series board. These configuration settings are described in this chapter.

ENSURE THAT THE POWER TO THE COMPUTER IS SWITCHED OFF BEFORE INSTALLING OR REMOVING ANY EXPANSION BOARD. OBSERVE HANDLING PRECAUTIONS NOTED IN SECTION 1.5. REPAIR OF DAMAGE CAUSED BY MIS-HANDLING IS NOT COVE RED UNDER THE AMPLICON WARRANTY. DO NOT MAKE ANY MODIFICATIONS OTHER THAN SWITCH OR JUMPER CHANGES TO A BOARD THAT IS ON EVALUATION

Please refer to the manufacturer's hardware manual supplied with the computer for instructions on how to remove the cover and install devices into an input/output slot. The PC247H2-8H2 Series board may be installed in any available position in the machine provided that there is no restriction specified for that location by the computer manufacturer. The PC247H2-8H2 Series board is factory configured ready to run with communications programs that normally support COM3 to COM 4 devices. If there are no other devices installed in the computer that are likely to cause conflicts, then for initial familiarisation purposes the board will need no configuration switch changes. Refer to the relevant paragraphs in section 2.5 if a change of base address, interrupt level or RS-422/485 jumper configuration needs to be made before installing the PC247H2-8H2 Series board in the computer.

PC247H2-8H2 Series

Page 7

2.3 Host Computer Requirements When installing one or more PC247H2-8H2 Series Data Communications Boards, ensure that the host computer has sufficient capacity. Take into account other boards or adapters that may be installed in the computer when assessing physical space, address space in the I/O map, interrupt levels and the power requirements. This dual channel serial communications board is suitable for use in any PC compatible computer that can provide a single ISA standard 16 bit I/O slot, with sufficient space for a half length card. If the only slot available is an 8 bit type, as on XT versions of the PC, then the higher interrupt levels will not be usable. Shared interrupts are not supported by XT versions. Most PC compatible computers, XT and AT 286/386/486 and above, including portables, can accommodate and provide power for this board. When installing the board in an 8 bit slot, ensure that the extension connector does not foul any baseboard components. The original specification of the ISA bus as found in the IBM PC AT allowed the sharing of interrupts by the use of a rearm register. The Amplicon PC 24XH2 board fulfils the requirements of interrupt sharing completely. Many so called compatibles are not true compatibles and do not allow the sharing of the interrupts 3 and 4 with the standard onboard com ports 1 and 2. This incompatibility requires the changing of SW3 to a different free IRQ from the default settings. However the board can share interrupts with its self and other compatible devices, provided the Amplicon drivers are used.

2.4 Configuration Switch and Jumper Settings Before mounting this board in the host computer, the configuration needs to be set to the user's requirements. Setting is by means of on-board in-line switches and pluggable jumpers whose functions are described below. The factory set configuration will suffice for many users needs.

2.4.1 Base Address Selection The port base address can be individually set for each channel. Each base address can be set at any eight bit boundary within the range 000 to 7F816. The only restrictions on addresses within this range are those brought about by pre-allocations or conflicting port assignments, the user must therefore ensure that:-

1. Both channels are NOT set to the same port base address. 2. Neither channel is set to an address already uti lised within the host

computer, nor by any other peripheral. To assist the user in choosing suitable base addresses for each channel, the standard I/O map and the ports normally allocated to communication channels COM1 through COM8 are tabled in sections 2.4.1.3 and 2.4.1.4. Many computers already have at least one serial port built in, and this port is normally allocated the COM1 address. If two ports are in-built, then they will normally be set at COM1 and COM2 addresses. In this situation, if these addresses are required for the port base addresses on the PC247H2-8H2 Series board, potential contention problems can be solved by disabling the in-built serial ports. Refer to the host PC or I/O adapter instruction manual for information on disabling these ports.

PC247H2-8H2 Series

Page 8

2.4.1.1 Factory Settings for the Channel Base Addre sses

SW1 Channel 1 (Upper connector) COM3 (3E816) SW2 Channel 2 (Lower connector) COM4 (2E816)

2.4.1.2 User Configured Base Addresses Each channel has a separately identified in-line switch bank to set its port base address. Channel 1 is set by SW1 and Channel 2 by SW2, the operation of each switch being identical. Figure 2.1 below shows the layout of the eight pole switch used for each setting. Four examples are shown, corresponding to the normal communication ports COM1 to COM4. The settings apply equally to switches SW1 or SW2. The most significant hex digit (MSD) is set in the range 0-7 by the three most left switches, the middle hex digit is set in the range 0-F by the next four switches and the least significant digit (LSD) by the most right single switch. Note that only the highest bit of the LS hex digit is available for setting, the remaining bits being zero. LSD can therefore only be set to 0 or 8. The intermediate addresses are automatically allocated to the selection of individual registers of the Universal Asynchronous Receiver/Transmitter (UART, aka ACE), used for each channel.

Please note that the switch type fitted to your board may vary in appearance to the above. On these drawings the black square

indicates the direction of the switch lever

FIGURE 2.1 SWITCH SELECTION OF CHANNEL BASE ADDRESS ES

This example shows Base Address 3F8 (COM1) selected

ON

1 2 3 4

| 4 0 0

1 0

| 8

| 1 0

| 2 0

| 4 0

| 8 0

| 1 0 0

| 2 0 0

< Mid Digit > LSD < MSD >

5 6 7 8

This example shows Base Address 2F8 (COM2) selected

This example shows Base Address 3E8 (COM3) selected

This example shows Base Address 2E8 (COM4) selected

ON

1 2 3 4

| 4 0 0

1 0

| 8

| 1 0

| 2 0

| 4 0

| 8 0

| 1 0 0

| 2 0 0

< Mid Digit > LSD < MSD >

5 6 7 8

ON

1 2 3 4

| 4 0 0

1 0

| 8

| 1 0

| 2 0

| 4 0

| 8 0

| 1 0 0

| 2 0 0

< Mid Digit > LSD < MSD >

5 6 7 8

ON

1 2 3 4

| 4 0 0

1 0

| 8

| 1 0

| 2 0

| 4 0

| 8 0

| 1 0 0

| 2 0 0

< Mid Digit > LSD < MSD >

5 6 7 8

PC247H2-8H2 Series

Page 9

2.4.1.3 PC I/O Map The standard PC/AT I/O map assignments are listed in Figure 2.2 below. I/O addresses 00016 to 0FF16 may be reserved for the PC system board use.

Hex Range Usage

1F0 - 1FF Hard Disc (AT) 200 - 20F Game/Control 210 - 21F Reserved 238 - 23B Bus Mouse 23C - 23F Alt. Bus Mouse 270 - 27F Parallel Printer 2B0 - 2DF EGA 2E0 - 2E7 GPIB (AT) 2E8 - 2EF Serial Port COM4 2F2 - 2F7 IRQ 9, 2-7 Re-arm 2F8 - 2FF Serial Port COM2 300 - 31F Prototype Card 360 - 36F Network 378 - 37F Parallel Printer 380 - 38F SDLC 3A0 - 3AF SDLC 3B0 - 3BB MDA 3BC - 3BF Parallel Printer 3C0 - 3CF EGA 3D0 - 3DF CGA 3E8 - 3EF Serial Port COM3 3F0 - 3F7 Floppy Disc 3F8 - 3FF Serial Port COM1 6F2 - 6F7 IRQ 10-15 Re-arm

FIGURE 2.2 PC I/O MAP ASSIGNMENTS

2.4.1.4 COM1 to COM8 Port Address Allocation Only four serial communications ports are allocated in the PC I/O map. More than four ports are often required, and Figure 2.3 lists the addresses usually allocated by hardware and software manufacturers to the serial ports COM1 to COM8. All these addresses are within the range of the PC 247-8H2 Series flexible addressing system. Serial Port Hex Range COM1 3F8 - 3FF ) COM2 2F8 - 2FF ) Standard I/O COM3 3E8 - 3EF ) Allocations. COM4 2E8 - 2EF ) COM5 280 - 287 COM6 288 - 28F COM7 290 - 297 COM8 298 - 29F

FIGURE 2.3 COM1 TO COM8 ALLOCATIONS

2.4.2 Interrupt Level Selection (IRQ)

PC247H2-8H2 Series

Page 10

Switch settings on the board allow each channel 1 and 2 to be set to any one of eight IRQ levels in the range IRQ 3-5, IRQ 7, IRQ 10-11 or IRQ 15. Each interrupt may be selected as shared or non-shared type, and if both channels are selected as shared interrupts, then the IRQ level may be the same on each channel. The settings of the IRQ levels and the sharing facility for each channel are all set up on an eight pole in-line switch, SW3. The layout of the switch and the function of each pole is shown in Figure 2.4, and the switch codes for the selectable levels are shown in the table in Figure 2.5.

Please note that the switch type fitted to your board may vary in appearance to the above. On these drawings the black square

indicates the direction of the switch lever

FIGURE 2.4 SWITCH SELECTION OF INTERRUPT LEVELS

CHANNEL 1 CHANNEL 2 INTERRUPT INTERRUPT

SWITCH SW3 SETTING REQUEST SHARED RE-ARM

1 2 3 4 5 6 7 8 LEVEL ADDRESS

OFF OFF OFF OFF OFF OFF OFF OFF IRQ 3 NO N/A OFF OFF OFF ON OFF OFF OFF ON IRQ 4 NO N/A OFF OFF ON OFF OFF OFF ON OFF IRQ 5 NO N/A OFF OFF ON ON OFF OFF ON ON IRQ 7 NO N/A OFF ON OFF OFF OFF ON OFF OFF IRQ 10 NO N/A OFF ON OFF ON OFF ON OFF ON IRQ 11 NO N/A OFF ON ON OFF OFF ON ON OFF IRQ 12 NO N/A OFF ON ON ON OFF ON ON ON IRQ 15 NO N/A ON OFF OFF OFF ON OFF OFF OFF IRQ 3 YES 2F3 ON OFF OFF ON ON OFF OFF ON IRQ 4 YES 2F4 ON OFF ON OFF ON OFF ON OFF IRQ 5 YES 2F5 ON OFF ON ON ON OFF ON ON IRQ 7 YES 2F7 ON ON OFF OFF ON ON OFF OFF IRQ 10 YES 6F2 ON ON OFF ON ON ON OFF ON IRQ 11 YES 6F3 ON ON ON OFF ON ON ON OFF IRQ 12 YES 6F4 ON ON ON ON ON ON ON ON IRQ 15 YES 6F7

FIGURE 2.5 INTERRUPT LEVEL SWITCH CODES

This example shows both channels set to IRQ level 10 with shared interrupts.

This example shows Channel 1 set to IRQ level 4 and Channel 2 set to IRQ level 3. Both

channels interrupts not shared. (Factory default setting)

1 2 3 4

| ON

1 0

| 1

| 2

| 4

Shared Interrupt

< Channel 2 < Channel 1

IRQ code

5 6 7 8

| ON

| 1

| 2

| 4

Shared Interrupt

IRQ code

ON

1 2 3 4

| ON

1 0

| 1

| 2

| 4

Shared Interrupt

< Channel 2 >

< Channel 1 >

IRQ code

5 6 7 8

| ON

| 1

| 2

| 4

Shared Interrupt

IRQ code

ON

PC247H2-8H2 Series

Page 11

2.4.2.1 Factory Settings for the IRQ Levels

The IRQ switches are set at the factory with channel 1 on IRQ4 and channel 2 on IRQ3, both non-shared. These are the standard IRQ levels for COM1/3 and COM2/4 respectively. The original specification of the ISA bus as found in the IBM PC AT allowed the sharing of interrupts by the use of a rearm register. The Amplicon PC 24xH2 boards fufill the requirements of interrupt sharing completely. Many so called compatibles are not true compatibles and do not allow the sharing of the interrupts 3 and 4 with the standard onboard com ports 1 and 2. This incompatibility requires the changing of SW3 to a different free IRQ from the default settings. However the board can share interrupts with its self and other compatible devices, provided the Amplicon drivers are used.

2.4.2.2 Interrupt Configuration The interrupt operations comply with the requirements laid down in the Industry Standard Architecture (ISA) for the Personal Computer Bus. The interrupt request line, IRQ 3-5, IRQ7, IRQ10-12 or IRQ15, signals the host PC (Permanent Master) that the PC247H2-8H2 Series adapter requires service. The host PC processor acknowledges the interrupt and takes the required action with the appropriate service routine.

Non-shared Interrupts When enabled, non-shared interrupts allow only one device to use an interrupt request line at any one time. When the interrupts are turned ON, the serial port currently using IRQn drives it to a LOW state. The port generates an interrupt by turning the driver into its high impedance state allowing it to be pulled to a HIGH level by a resistive pull up on the host PC. IRQn remains at a HIGH state until the interrupt is acknowledged by the appropriate write or read. When the serial board port does not require interrupt service, the user should ensure that its active interrupt drive is removed, allowing the use of the IRQn line by another port or adapter. The IRQn can be put into its high impedance state by disabling all interrupts using bit 3 of the Modem Control Register (UART MCR). Not all software drivers do this. In non shared mode the board will not always operate on an interrupt level assigned to any other device. For this reason the board will not always operate on interrupt levels 3 & 4, i.e. the normal interrupts assigned to COM3 & COM4, if COM1 and COM2 are present in the PC. This is because COM1 & COM2 use interrupt levels 4 & 3 respectively and most standard communications boards do not support shared interrupts.

Shared Interrupts Interrupts may only be shared with other devices that support shared interrupts. Shared interrupts allow more than one device to use a common interrupt request line. The shared interrupt concept requires that the interrupting channel indicates the need for service by a pulse rather than a level. Each port of the serial communications board has an interrupt status latch that is set before an interrupt is initiated. The processor starts an interrupt sequence by arming the PC interrupt controller on the leading edge of a negative pulse (125 to 1000 ns) occurring on the interrupt request line. The trailing edge signals the interrupt controller to cause the interrupt. Each properly configured, interrupt-sharing adapter on a common interrupt level monitors the allocated IRQ line. When any adapter, including the PC247H2-8H2 Series board, pulses the line,

PC247H2-8H2 Series

Page 12

no other adapter will issue an interrupt until it is re-armed. The interrupt status latch is reset, and the interrupt level re-enabled, by the interrupt service routine issuing a global re-arm by writing to the appropriate port. Further information on handling shared interrupts can be found in an IBM Technical Reference Manual or other advanced reference documentation relating to the host PC. If shared interrupts are selected, then the same IRQ level may be set for both channels and can be shared with other boards in the PC that similarly handle shared interrupts. Note that shared interrupts are only supported by compliant AT/286 and above compatible computers. Careful checking of interrupt assignment in your system is recommended prior to board installation. The user must ensure that no contention exists when selecting an IRQ level. The normal allocation of hardware interrupt levels is tabled below.

PC247H2/8H2(i) Host PC Host PC Host PC Selected IRQ Interrupt Description IRQ Level Name Number (hex) of Usage — IRQ 0 8 Timer Not available on the — IRQ 1 9 Keyboard Bus Connectors — IRQ 2 A Int 8 - 15 3 IRQ 3 B COM or SDLC IRQ 2-7 4 IRQ 4 C COM or SDLC available on 5 IRQ 5 D LPT XT and AT — IRQ 6 E Floppy Disk 7 IRQ 7 F LPT — IRQ 8 70 Real Time Clock — IRQ 9 71 Re-directed to IRQ2 10 IRQ10 72 Unassigned IRQ 8-15 11 IRQ11 73 Unassigned available on 12 IRQ12 74 Unassigned (or PS2-mouse) AT — IRQ13 75 Co-processor only — IRQ14 76 Hard Disk 15 IRQ15 77 Unassigned

FIGURE 2.6 INTERRUPT LEVEL ASSIGNMENTS

2.4.3 RS-485 Full Duplex / Half Duplex Operation

An RS-485 port on the PC248H2(i) can be used in either full duplex (simultaneous transmission and reception over two independent wire pairs) or half duplex (sequential transmission or reception over a single wire pair). In full duplex operation, a separate transmitter and receiver circuit is employed, and in this mode the transmitter can be left in its enabled state at all times. In half duplex receive operation, the transmitter must be disabled by switching to its high impedance state to allow reception of data over the same serial lines. The RS-485 ports are provided with all the data input/output terminals required for full duplex operation. If half duplex operation is required, then external connection changes must be considered. Also check that the termination resistor, paragraph 2.5.4, is correctly connected or disconnected for the requirements of the network.

PC247H2-8H2 Series

Page 13

2.4.3.1 Selection of Full/Half Duplex The software drivers for Windows 95, 98, ME, NT, 2000, XP, and Linux drivers supplied with the Amplicon PC248H2(i) board, incorporates a software selectable half or full duplex mode of operation, called special half duplex. This is selected by linking J60 and J80 in the 2-3 position and allowing the software to control full or half duplex. To remain compatible with the old PC248 boards, the boards still retain the former functionality on J60 J61 J80 and J81 as described below. Jumper J60 for channel 1 and jumper J80 for channel 2 are individually set for full or half duplex operation. The settings must be made in accordance with the following table. Default settings are both channels full duplex, but the jumper links are provided (hung on one pin) for half duplex operation. It is important that the appropriate connector wiring for full or half duplex is properly implemented. The connections are discussed in paragraph 3.6.

CHANNEL JUMPER FULL DUPLEX HALF DUPLEX SPECIAL HALF DUPLEX

1 (Upper) J60 Out 1-2 2-3 2 (Lower) J80 Out 1-2 2-3

FIGURE 2.7 JUMPER SETTING FOR FULL/HALF DUPLEX

2.4.3.2 Selection of Local Echo On/Off in Half Dupl ex Operation The factory default configuration of jumpers J61 and J81 causes the transmitted data to be echoed to the receiver in half duplex operation. If this echo is not required, continuous operation of the receiver must be inhibited by inserting the appropriate jumper. This change ensures that the RS-422/485 receiver is enabled/disabled in opposite phase to the transmitter. Default settings are both channels echo ON (full duplex), but the jumper links are provided (hung on one pin) for echo OFF operation. The ‘Local Echo’ operation provided with some serial communications programs is a separate facility, and should normally be turned off. For full duplex operation, the jumper J61 or J81 must be in its default condition (out) for the receiver to be continuously enabled. Echo is not appropriate to full duplex operation.

CHANNEL JUMPER ECHO ON ECHO OFF

1 (Upper) J61 Out In 2 (Lower) J81 Out In

FIGURE 2.8 JUMPER SETTING FOR ECHO

2.4.4 Transmission Line Termination

2.4.4.1 Termination Resistors for RS-422/485 Receiv ers

Operation of RS-422/485 systems requires that the lines be terminated at the final receiver. The simplest termination is by a line-to-line resistor, and provision is made to connect this 120Ω terminator on the data and control inputs of each RS-422/485 channel. Correct termination is built into the RS-232 receivers. The RS-422/485 CTS control line receivers are permanently terminated and the data input terminator resistors can be disconnected by removal of a jumper for each channel. Jumpers J62

PC247H2-8H2 Series

Page 14

and J82 are factory fitted, and should be retained in position as required to terminate the following differential receiver line pairs:-

RECEIVER JUMPER Channel 1 Rx Data Terminator J62 Channel 2 Rx Data Terminator J82

Further notes on RS-422 and RS-485 operation are given later in Chapter 4, 'Using the Serial Communications Boards'

2.4.5 Data Rate Range selection

The PC247H2-8H2 series all support two data rate ranges. One compatible with the previous PC247-9 series and the other supports increased data rates up to 1 MBaud when using the Windows 95, 98, ME, NT, 2000, XP, or Linux driver supplied. Selection between these ranges is by means of jumper link J4.

JUMPER LOW SPEED

Up to 115 kBaud

HIGH SPEED

Up to 1 MBaud

J4 1-2 2-3

2.4.6 Switch and Jumper Factory Settings Summary The PC247H2-8H2 Series boards can be reset to their factory defaults by re-configuring the board according to the following tables.

Switch Function Value Switch Settings SW1 Channel 1 Address 3E8 (Hex) 1-off, 2-on, 3-on, 4-on, 5-on, 6-on, 7-off, 8-on

SW2 Channel 2 Address 2E8 (Hex) 1-off, 2-on, 3-off, 4-on, 5-on, 6-on, 7-off, 8-on

SW3 Interrupt Levels IRQ 4 and 3 1-off, 2-off, 3-off, 4-on, 5-off, 6-off, 7-off, 8-off

Jumper Function PC247H 2(i) PC248H2(i) J4 Hi Data Rate Range Hi Hi

J60 Channel 1 Full Duplex N/A 2-3

J61 Channel 1Echo N/A Out

J62 Channel 1 Termination N/A In

J80 Channel 2 Full Duplex N/A 2-3

J81 Channel 2 Echo N/A Out

J82 Channel 2Termination N/A In

FIGURE 2.9 FACTORY JUMPER SETTING SUMMARY

PC247H2-8H2 Series

Page 15

2.5 Software Installation 2.5.1 Software extraction from the Softman

The Softman CD enables you to download the software needed for your installation on to your own hard disk. This facility allows you to access the manual and software for the product you have purchased from Amplicon Liveline Ltd. There are a number of data sheets and FAQs to help you get the best from our products. To Download the software double click on the 'Software' button adjacent to the appropriate product (PC247-8H2). Be sure to 'OPEN' the file rather than 'SAVE' , otherwise you will need to run the file to expand the programs onto your hard disk. DO NOT change the download directory, leave it as c:\amplicon\serial, and select 'Unzip' to initialise the transfer. A Readme file will be displayed showing you the latest changes and further installation instructions. The procedure varies depending on which operating system you wish to install as detailed below.

2.5.2 Windows 95 & 98 Software Installation

The Amplicon 95/ 98 serial driver is an enhanced version of the standard Microsoft Windows 95 Serial Driver, especially designed to support the enhanced features of Amplicon Liveline's serial boards and converters. It supports baud rates up to and beyond 1 MBaud. It supports ISA shared interrupts, as implemented on Amplicon serial boards, enabling more than one serial device to share an interrupt resource successfully without conflicts. It supports options for RS-485 half-duplex transmission enabling multiple RS-485 ports to communicate in half duplex (two wire) mode. This driver is capable of driving the standard Amplicon RS-485 boards, as well as external RS-485 adapters. Although this driver is based on Microsoft's standard driver it is not a Microsoft product. The Softman CD enables you to download the software needed for your installation on to your own hard disk. This facility allows you to access the manual and software for the product you have purchased from Amplicon Liveline Ltd. There are a number of data sheets and FAQs to help you get the best from our products.

PC247H2-8H2 Series

Page 16

This assumes the Amplicon serial software has been extracted from the CD-ROM into the "C:\AMPLICON\SERIAL" directory.

1. Ensure that your serial communications board is installed in your PC, taking note of any base address and interrupt settings.

2. Switch your computer on & start Windows 95 or 98.

3. Go to Control Panel and double click on the "Add New Hardware" icon.

4. Click "Next", click on the "No" radio button, and

then click "Next" again. 5. Select "Ports" from the list of hardware available, and

click "Next". 6. Click on the "Have Disk" button and type

"C:\AMPLICON\SERIAL", then click on "OK". Select PC24xh.inf

3.

4.

5.

6.

PC247H2-8H2 Series

Page 17

7. Click on the type of port (RS232 or RS485) from the list, then click on "Next", then click on "Next" again ignoring the settings.

8. The serial driver is now copied and installed into your machine. Click on "Finish".

9. When prompted to shut down the computer, do not do so, see steps 10 and 11.

10. For each subsequent Amplicon COM port that you want

to install simply follow the instructions above from step 3, but instead of clicking on the "Have Disk" button at step 6, simply select the manufacturer "Amplicon Liveline" and go to step 7. N.B. no more files will be copied during step 8.

11. When you reach the end of the Hardware Set-up

procedure do not restart the computer. Instead configure the COM ports that the Add New Hardware procedure has detected as detailed below in "Configuring COM Ports".

7.

8 .

9.

10.

PC247H2-8H2 Series

Page 18

2.5.3 Windows 95 & 98 Configuring COM Ports

1. Go to Control Panel and double click on the "System" icon, then click on the "Device Manager" tab.

2. Double click on the "Ports" icon to show a list of available

serial and parallel ports. 3. Ports that are using the Amplicon Serial Driver should be

labelled "Amplicon ISA RS232 Port", "Amplicon ISA RS485 Port", "Amplicon PCI RS232 Port" or "Amplicon PCI RS485 Port".

4. Double click on an Amplicon COM port to bring up the

properties sheet for that port, and then click on the "Resources" tab.

5. To change the settings for that COM port first ensure that

the "Use Automatic Settings" check box has been cleared, and then select "Basic configuration 4" from the "Settings based on" list box.

6. Double click on the

Resource type (IRQ or base address) that you want to change, and edit it to your satisfaction.

7. The number of the COM

port may be changed after clicking on the "Resources" tab.

8. Click "OK" once the

properties have been edited to your satisfaction. Renumbered COM ports may not be listed correctly until the "Refresh" button is clicked on the "Device Manager" sheet.

Repeat this for every Amplicon COM port that you have installed, and then restart you system.

2.

4.

5.

PC247H2-8H2 Series

Page 19

NOTES When installing new hardware Windows 95 and 98 very often will set up the hardware at an incorrect base address and/or IRQ level. Always check the port settings in Device Manager before restarting your system, any configuration problems can be resolved here by following the instructions in the Configuring COM ports section of this readme file. Please note that the Amplicon Serial Driver cannot share IRQs with other manufacturers serial boards that do not conform to the IBM shared interrupts specification. They will also fail to work if sharing interrupts with a disabled motherboard resource such as USB port (IRQ 12) or communications ports 1 and 2. Five "Basic configurations" have been provided in Device Manager for the user. Configurations 0-3 set the port resources to the standard settings for COM 1-4 respectively. Basic configuration 4 allows the user to set their own base address and IRQ level. The Basic configuration property must always be set to 4 if the user has their board set up to a non-standard base address or IRQ level. 2.5.4 Windows NT Software installation

The Amplicon NT serial driver is an enhanced version of the standard Microsoft Windows NT serial Driver, especially designed to support the enhanced features of Amplicon Liveline's serial boards and converters. It supports rates beyond 1 MBaud. It supports ISA shared interrupts, as implemented on Amplicon serial boards, enabling more than one serial device to share an interrupt resource successfully without conflicts. It supports options for RS-485 half-duplex transmission enabling multiple RS-485 ports to communicate in half duplex (two wire) mode. This driver is capable of driving the standard Amplicon RS-485 boards, as well as external RS-485 adaptors.

Although this driver is based on Microsoft's standard driver it is not a Microsoft product. TO Install, run c:\amplicon\serial\setup.exe and follow the instructions given. Click on 'Proceed' and then 'Exit. Do not forget, you must restart for the installation to be completed.

2.5.5 Windows NT Configuring COM ports

COM ports can be configured by means of the "Amplicon" control panel applet that has been installed into your control panel. An option has been included in the Amplicon Control Panel Utility that allows the Amplicon driver to be removed and the system restored to the standard Microsoft configuration. Please note that the Amplicon Serial Driver cannot share IRQs with other manufacturers serial boards that do not conform to the IBM shared interrupts specification. They will also fail to work if sharing interrupts with a disable motherboard resource such as USB port (IRQ 12) or communications ports 1 and 2.

2.5.6 Windows 2000 Installation

This assumes the Amplicon serial software has been extracted from the CD-ROM into the “C:\AMPLICON\SERIAL” directory.

1. Ensure that your serial communications board is installed in your PC, taking note of any base address and interrupt settings. Ensure J4 is set to the ‘HI’ postion.

2. Switch your computer on and start Windows 2000.

PC247H2-8H2 Series

Page 20

3. Go to Control Panel and double click on the “Add New Hardware” icon.

4. Click “Next” and then Add/Troubleshoot a device.

5. Select “Add a new device”.

6. When asked whether you want to search for new hardware, select “No, I want to select hardware from a list”.

7. Select “ports (COM&LPT)” from the list of hardware available, and click “Next”.

8. Click on the “Have Disk” button and type “C:\AMPLICON\SERIAL”, then click on “OK”.

9. Click on the type of port from the list:

Amplicon Hi-Speed RS232 Port for PC247H2 and PC248H2

Amplicon Hi-Speed RS485 Port for PC248H2 and PC248H2

10. Click on “Next”.

Windows will say that it could not detect the settings for the device automatically and then prompt you to specify the resources tor your board.

11. To change the settings for that COM port first ensure that the “Use Automatic Settings” check box has been cleared, and then select “Basic configuration 8” from the “Settings based on” list box.

12. Double click on the Resource type (IRQ or base address) that you want to change, and edit it to your satisfaction.

13. Click “OK”.

Windows will prompt you to say that it will use the default settings to install the device.

14. Select Next.

Windows may say that the driver has not been digitally signed.

15. Select “YES” to continue the installation.

16. Click on “Finish”. The serial driver is now installed on your machine. If you wish to review the resources, you can click resources.

17. When prompted to shut down the computer, only do so if you have installed the necessary COM ports. Otherwise install further COM ports by following the instructions above from step 3, but instead of clicking “Have Disk” at step 8, select the manufacturer “Amplicon Liveline” and proceed to step 9. NB no more files will be copied during additional COM port installation.

2.5.7 Windows 2000 Configuring COM Ports

To change resources assigned to ISA ports:

1. Go to Control Panel and double click on the “Hardware” tab, and then click on the “Device manager” button.

2. Double click on the “Ports” icon to show a list of available serial and parallel ports.

3. Ports that are using the Amplicon Serial Drivers will be listed as follows:

Amplicon RS232 Port Amplicon RS485 Port Amplicon Hi-Speed RS232 Port Amplicon Hi-Speed RS485 Port

4. Double click on an Amplicon COM port to bring up the properties sheet for that port.

Default baud, flow control, half-duplex mode, and COM port number can be changed on the “Port Settings” tab.

PC247H2-8H2 Series

Page 21

ISA board hardware settings can be changed on the “Resources” tab. Notes When installing new hardware, Windows 2000 will almost always initially set up the hardware at an incorrect base address and/or IRQ level. When you are prompted to specify the hardware settings, always check the port settings are correct before restarting your system.

Please note that the Amplicon Serial Drivers cannot share IRQs with other manufacturers’ ISA serial boards that do not conform to the IBM shared interrupts specification. They will also fail to work if sharing interrupts with a disabled motherboard resource such as a USB port (IRQ12) or communications ports 1 and 2 if the motherboard still ties up the interrupt lines of its resources after disabling them.

Nine "Basic configurations" have been provided in Device Manager for the user. Configurations 0, 2, 4 and 6 set the port resources to the standard settings for COM ports 1-4 respectively. Basic configurations 1, 3, 5 and 7 use the standard I/O base addresses for COM ports 1-4 respectively, but allow the IRQ level to be set by the user. Basic configuration 8 allows both the I/O base address and the IRQ level to be set by the user. 2.5.9 Linux Installation For installation and configuration instructions please refer to the documentation contained in the Amplicon Serial Driver.for Linux package on the Softman CD. The package contains the source code for two kernel modules: the Amplicon serial driver itself (ampser) and a module for handling shared interrupts on Amplicon ISA serial boards (isa_global_rearm). Both of these are required for the PC247-8H2 boards.

2.6 Installation Testing

Many applications packages include a self-test feature, and when the hardware and software have been satisfactorily installed, any such test should be performed to check correct operation. If no self-test is available, or a problem occurs, see the later section 4.4, 'Testing and Troubleshooting'.

PC247H2-8H2 Series

Page 22

3 MAKING THE CONNECTIONS

This chapter describes the signal and control connections that the user must make between the PC247H2-8H2 Series board and any external serial communications devices. These input/output connections are made through the D type plugs protruding from the PC adapter slot corresponding to the chosen board position. For completeness of information, the standard PC back-plane bus connections are also shown in paragraph 3.7.

3.1 External Connections Connections to the RS-232 and/or RS-422/485 lines are made via 9 pin D type connectors on the rear panel. The on-board connectors are male and the mating sockets are available as accessories. Provision is made for securing by screw jacks. Each channel has its individual connector, located as shown in Figure 3.5 and assigned as follows:-

Channel 1 (Upper) Channel 2 (Lower) PC247H2(i) PL60-9 way RS-232 PL80-9 way RS-232 PC248H2(i) PL60-9 way RS-422/485 PL80-9 way RS-422/485

The non-isolated 9 way RS-232 ports conform to industry standard pinouts, and will support commercially available cables and adapters.

3.2 RS-232 9 way Port

This 9 pin D connector (PL-80) is fitted to the lower RS-232 port of the PC247H2(i) and the pin-out conforms to the industry standard.

FIGURE 3.1 RS-232 9 WAY PORT PIN DESIGNATIONS 3.3 RS-422/485 9 way Port

This 9 pin D connector is fitted to the upper (PL-60) and lower (PL-80) RS-422/485 port of the PC248H2(i). Two pin assignment options are available for the 9 way RS-485 connector. These are selectable by means of jumper links J63-71 for channel 1 and links J83-91 for channel 2.

5 9

4 8

3 7

2 6

1

Ring Indicator (RI) Clear To Send (CTS) Request To Send (RTS) Data Set Ready (DSR)

Reference Signal Ground (SG)

Data Terminal Ready (DTR) Transmitted Data (TXD)

Data Carrier Detect (DCD) Received Data (RXD)

PC Chassis Ground

PC247H2-8H2 Series

Page 23

3.3.1 RS-422/485 9 way Port Amplicon pin assignment This is the factory set default pinout compatible with the PC247H2-8H2 series boards. To select this pinout J63-71 for channel 1 and J83-91 for channel 2 should be set in positions 1-2, as shown below.

FIGURE 3.2 RS-422/485 AMPLICON STANDARD PORT PIN DE SIGNATIONS 3.3.2 RS-422/485 9 way Port Alternative pin assignm ent

This is the alternative pinout compatible with the Moxa Rocketport series of boards. To select this pinout J63-71 for channel 1 and J83-91 for channel 2 should be set in positions 2-3, as shown below.

FIGURE 3.3 RS-422/485 ALTERNATIVE STANDARD PORT PIN DESIGNATIONS

5 9

4 8

3 7

2 6

1

Clear To Send (CTS) - Clear To Send (CTS) - B' Request To Send (RTS) - B Request To Send (RTS) - A

Reference ground Received Data - A'

Received Data - B'

Transmitted Data - A Transmitted Data - B

PC Chassis Ground

In full duplex operation, pins 4 and 5 provide the balanced Tx O/P, pins 8 and 9 provide the balanced Rx I/P

In half duplex operation, pins 4 and 5 must be externally linked to pins 8 and 9 to provide transceiver I/P and O/P

5 9

4 8

3 7

2 6

1

Received Data - B' Received Data - A' Clear To Send (CTS) - Clear To send (CTS) - A'

Transmitted Data - B Transmitted Data - A

Request To Send (RTS) - A

Reference Ground Request To Send (RTS) - B

PC Chassis Ground

PC247H2-8H2 Series

Page 24

3.4 Input/Output Connector Locations

The two serial channel input/output connectors are mounted on the panel and the positions of the two connectors for the various board types are shown in Figure 3.4 below.

PC247H2(i) PC248H2(i)

FIGURE 3.4 INPUT/OUTPUT CONNECTOR LOCATIONS FOR ALL BOARD TYPES

Upper Connector PL-60 Channel 1 9 pin RS-232 Pin-outs shown in Figure 3.1 Lower Connector PL-80 Channel 2 9 pin RS-232 Pin-outs shown in Figure 3.1

Upper Connector PL-60 Channel 1 9 pin RS-422/485 Pin-outs shown in Figure 3.2/3 Lower Connector PL-80 Channel 2 9 pin RS-422/485 Pin-outs shown in Figure 3.2/3

PC247H2-8H2 Series

Page 25

3.5 Connector Wiring for RS-422/485 Full/Half Duple x In the full duplex position, the serial RS-422/485 data signals are transmitted on the wire pair Tx-A (pin 4) and Tx-B (pin 5) and the incoming signals are received on Rx-A' (pin 8) and Rx-B' (pin 9). In half duplex RS-485 operation, the data signals are both transmitted and received on the two pairs externally wired in parallel. In addition to the external connections for half duplex operation, jumpers J60/J80 and J61/81 must also be set for full or half duplex operation with or without echo. See paragraph 2.4.3 for the jumper settings and Figure 3.5 for the connector wiring to provide full duplex or half duplex operation. The flow control signals, Request To Send (RTS) and Clear To Send (CTS) are also available on the connector, and will be required for use in some full duplex applications. If these control signals are not required for connection to the device at the other end of the link, the signals may be looped back as shown dotted in the diagram. Looping in this way allows the RTS signal to be monitored, which is a requirement of some programs.

THIS DIAGRAM REFERS TO THE AMPLICON STANDARD PINOUT . FOR ALTERNATIVE PIN ASSIGNMENTS REFER TO FIGURE 3.3

FIGURE 3.5 CONNECTIONS FOR FULL AND HALF DUPLEX OPE RATION 3.5.1 Choice of Cable

As speeds and distances of communication increase the choice of cable over which the communication is to take place becomes critical. Amplicon recommend Belden Cable, part no. 8132 for use in long distance high speed RS-422 & RS-485 networks. This is multi-shielded twisted pair cable. It has a capacitance of 20pF/m and characteristic impedance of 120 ohms. It is available from Amplicon. Contact our sales for full information on lengths and availability.

Half Duplex Connection Transmit and Receive over same circuit

Full Duplex Connection Separate Transmit and Receive

Tx - B

Tx - A

RTS - A RTS - B

5

4

3

2

1

Received Data

Transmitted Data

9

8

7

6

Rx - B'

Rx - A'

CTS - B' CTS - A'

Tx - B

Tx - A

RTS - A RTS - B

5

4

3

2

1

Transceived Data

9

8

7

6

Rx - B'

Rx - A'

CTS - B' CTS - A'

PC247H2-8H2 Series

Page 26

3.6 The Ground Connections

Each connector is equipped with two or more different ground connections and care must be taken in the use of these grounds and the cable design to ensure that the EMC requirements are met, and that isolation integrity is maintained in the case of the boards with isolated input/output. The connector pin-out is such that commercially available cables and adapters are normally usable without modification, but the user must be aware of the requirements to maintain isolation when the devices at each end are not at nominal earth potential. The choice of proper, screened cables is also important for the system to maintain Electro-Magnetic Compatibility.

3.6.1 Ground Connections for Non-isolated Boards For the PC247/8H2 non-isolated boards, the ground connections are normal for a serial interface and remain compatible with the earlier PC47/8/9AT range of boards. The various ground connections are:- RS-232 Ground Connections

Reference Signal Ground (Pin 5 of 9 way) is internally connected to the PC signal ground and should be externally connected to the Signal Ground pin of the RS-232 device at the other end of the link. Connector Shell is internally connected to the PC chassis ground. To maintain shield integrity, metal connector hoods should be used, preferably at both ends. These hoods make contact with the connector shell and the cable screen so maintaining an overall shield.

RS-422/485 Ground Connections Reference Ground is internally connected to the PC signal ground which is not normally required for the differential operation of RS-422/485 line pairs. This pin may be left unconnected. Connector Shell is internally connected to the PC chassis ground. To maintain shield integrity, metal connector hoods should be used, preferably at both ends. These hoods make contact with the connector shell and the cable screen so maintaining an overall shield.

3.6.2 Ground Connections for Isolated Boards For the PC247H2i-8H2i boards with isolated input/output, the various ground connections are:-

3.6.2.1 RS-232 Ground Connections

Reference Signal Ground (Pin 5 of 9 way) is internally connected to the isolated ground circuit and should be externally connected to the Signal Ground pin of the RS-232 device at the other end of the link. Any voltage appearing between this reference ground and the host PC ground is common mode and must not exceed 250 V peak. The internal resistance between these grounds is 1 MΩ.

PC247H2-8H2 Series

Page 27

Connector Shell is internally connected to the PC chassis ground. To maintain shield integrity, a metal connector hood should be used which must be connected to the cable screen at the host PC end. If the remote device is specifically at an elevated potential, then connecting the cable screen, and hence the chassis grounds, at both ends could void the isolation. It is therefore the best and safest practice to connect the cable screen at the host PC end only. See Figure 3.7 for an example of 9 pin isolated RS-232 connections to another DTE device.

FIGURE 3.6 9 PIN ISOLATED RS-232 CONNECTIONS TO ANO THER DTE DEVICE 3.6.2.2 RS-422/485 Ground Connections

Reference Ground is internally connected to the isolated signal ground which must be connected to the signal ground of the remote RS-422/485 device. Any voltage appearing between this reference ground and the host PC ground is common mode and must not exceed 250 V peak. The internal resistance between these grounds is 1 MΩ. Connector Shell is internally connected to the PC chassis ground. To maintain shield integrity, a metal connector hood should be used which must be connected to the cable screen at the host PC end. If the remote device is specifically at an elevated potential, then connecting the cable screen, and hence the chassis grounds, at both ends could void the isolation. It is therefore the best and safest practice to connect the cable screen only at the host PC end.

4

5 9

8 3

2

1

Ring Indicator (Not needed)

Clear To Send (CTS)

Request To Send (RTS)

Data Set Ready (DSR)

Reference Signal Ground (SG)

Data Terminal Ready (DTR)

Transmitted Data (TxD)

Data Carrier Detect (DCD)

Cable screen connection to hood and shell

Cable screen connection to hood and shell. Only make this connection if this

remote device is at nominal ground potential

Received Data (RXD) 7

6

4

5 9

8 3

2

1

7

6

RS-232 DTE with 9 pin connector

PC247H2i RS-232 lower port

PC247H2-8H2 Series

Page 28

4 USING THE SERIAL COMMUNICATIONS BOARDS

4.1 Why Isolate? The PC247H2I and the PC248H2i provide complete electrical isolation between any signals connected to a serial port, signals connected to the other port and the circuits of the host computer. In a compact office or laboratory environment such isolation may not be necessary, however in a wide-field industrial situation, serial digital communication can be disrupted by many types of contaminating signals, most of which can be eliminated by the proper use of isolation. Both digital input receivers and output drivers make use of opto-couplers to provide a signal path between external and internal circuits without any electrical connection being made. An opto-coupler comprises a Light Emitting Diode (LED) which is turned on by the incoming signal, and a photo-detector which receives the light and converts it into an electrical signal. The emitter and detector are mounted in a package that provides a light path together with high voltage insulation between the two sides. Power to the input/output circuits is provided by an isolated DC-DC converter, one for each channel. Interfering signals can come from a variety of sources and are often greater in amplitude than the desired signal. Such an interfering signal is 'common mode' and is effectively the potential difference between the zero-signal reference points of the signal source and receiver. By using the PC247H2i-8H2i isolated input and output boards, this potential difference appears across the isolation barrier and not in series with the signal as would be the case if direct connection was employed. The two ends of a link would normally have their grounds connected together through the signal ground line, the protective ground line and/or the cable shield. Such a connection has an impedance such that an interfering signal caused by a difference in ground potentials is likely to be a few volts in amplitude, maybe peaking to tens of volts. However there may be circumstances or fault conditions in which higher common mode voltages exist, and the circuits of the PC247H2i-8H2i are designed to hold off peak common mode voltages up to 250V. RS-232 standards allow a transition region of ±3.0 V, and within this region, signal variations will not be detected. If the signal (real or noise) is < –3.0 V, it will be detected as a mark for a data line or OFF for a control line. If the signal is > +3.0 V, it will be detected as a space for data or ON for a control signal. In RS-232 operations, any ground offset, noise, hum or other interference exceeding ±3.0 V peak amplitude will be detected as a real signal and corrupt the data or control functions.

DANGER High Voltage

BE AWARE DANGER OF ELECTRIC SHOCK

When the PC247H²i or the PC248H²i isolated board is in use in an open computer chassis, high voltages may be exposed on the connector and associated circuitry.

PC247H2-8H2 Series

Page 29

RS-422 and RS-485 standards provide a better level of ground noise immunity than RS-232, the maximum common mode voltages being –7.0 V to +7.0 V and –7.0 V to +12.0 V respectively for the two standards. However, any ground offset, noise, hum or other in terference exceeding these peak amplitudes will be detected as real sign als and may corrupt the data or control functions. Breaking the common ground connection by the use of the PC247H2i-8H2i isolated interface completely eliminates the detection of these interfering signals as real signals with no loss or corruption of data. In general, isolation is only required at one end of a data link, and Figure 4.1 illustrates the principle of the isolated interface and shows how the signal loop is self-contained and not subject to common mode interference. Multi-drop or broadcast systems with many RS-485 or RS-422 nodes on a single circuit may require all circuits to be isolated for error free serial data communication. The pinouts of the isolated PC247H2i-8H2i are configured so that the user may plug in standard cables and in many cases need not be concerned about making any changes to effect full isolation. If the cable is screened, with the screen connected to the D type shell and/or cover at one end, the overall screening will be maintained, together with proper implementation of the isolation.

FIGURE 4.1 ELIMINATION OF INTERFERING SIGNALS BY IS OLATION

Tx Data Rx Data

RTS CTS DSR DCD DTR

Signal GND Interfering

Signal

Non-isolated RS-232 Link with all

Data and Control Lines

Interfering signal is in

series with all data and control signals

and will cause corruption if the

amplitude exceeds the transition region levels

RI RS-232 DCE

Interface

RS-232 DTE

Interface Loop

Tx Data Rx Data RTS CTS DSR DCD DTR RI

One Port of PC247Hi

Opto- Couplers

Signal GND

Interfering Signal

ISOLATED RS-232 Link with all

Data and Control Lines

Interfering signal is across the isolation barrier and NOT in

series with the data or control lines and no corruption occurs

RS-232 DCE

Interface

RS-232 DTE

Isolated Interface

Tx Data Rx Data

RTS CTS DSR DCD DTR

RI

Tx Data Rx Data RTS CTS DSR DCD DTR RI

PC247H2-8H2 Series

Page 30

4.2 Application Notes As previously noted, many applications packages are designed to support data transfer over the standard serial communications ports. When set up as specified, and conventional multi-way cables and connectors are in use, then the interface will be transparent to the user. However, for special applications, particularly when use of the RS-485 interface is required, the following notes will be helpful.

4.2.1 Applicable Standards The prefix 'RS' signifies Recommended Standard, and the three interface types, RS-232, RS-422 and RS-485, supported by the Amplicon range of boards are all well defined in the appropriate standards publications. The functions and features of the data and control interfaces presented by the PC247H2-8H2 Series generally conform to normal industry practice employing a subset of the full standards. The RS-232 serial interface standard is now at revision E and its full title is EAI/TIA RS-232-E, "Interface Between Data Terminal Equipment and Data Communication Equipment Employing Serial Binary Data Interchange". Similar European standards CCITT V.24 and V.28 define an interface which is operationally compatible with RS-232. The RS-232 ports of the PC247H2 are designated as DTE (Data Terminal Equipment) in accordance with normal practice for a computer driven serial port. The current RS-232 standard specifies the 25 way male D type connector for DTE. Earlier revisions of the RS-232 standard did not specify the connector type. The full 25 lines are not required to support the common functions of RS-232, and IBM and other manufacturers frequently adopt a 9 way D type connector that provides all the necessary functionality. Where this 9 wire system is used, manufacturers conform to the pin-out configuration as shown in Figure 3.2, the channel 2 port of the PC247H2(i). The RS-422 interface is defined in the EIA/TIA standard RS-422-B, "Electrical Characteristics of Balanced Voltage Digital Interface Circuits". As stated, this standard defines the electrical characteristics but does not specify a connector type or pin-out configuration. The PC248H2(i) fully meets the RS-422 standard specification with communication via a 9 pin D type connector wired as shown in Figure 3.3 or 3.4. The RS-485 specification is also published as an EIA standard and is closely allied to the RS-422. The PC248H2(i) meets the requirements laid down in the RS-485 standard.

4.2.2 RS-232 Application Notes RS-232 was approved as a standard interface in 1969. Before and since that time this interface in its various revisions has been very popular despite its many shortcomings and usage outside its intended role. Most small computers now have an RS-232 interface as standard, or easily added, and many peripherals and instruments support this serial interface, but not all in the same way. Hence the application of an RS-232 connection needs careful study of the equipment manufacturers connections and methods before the devices are linked. However RS-232 lines are quite safe if wrongly connected, so the experimental use of a break-out box or 'hit and miss' methods of establishing communication are often employed.

PC247H2-8H2 Series

Page 31

4.2.2.1 Electrical Levels When checking out serial communications circuits, it is useful to know what signal levels to expect. The specified voltage levels of RS-232 data and control signals are summarised in the following table:-

Interchange Voltage –15 to –3 V +3 to +15 V Data Binary State 1 0 Data Signal Marking Spacing Control Function (RTS, DTR) OFF ON

The levels are specified relative to signal ground at 0 volts, (the remote device signal ground in the case of isolated ports), and the region between –3 and +3 volts is the transition region. The voltage levels transmitted by the PC247H2(i) data and control lines are about ±10 V.

4.2.2.2 Data Rates and Cable lengths The RS-232 standard specifies the data signalling rate up to 20 kBaud, but an RS-232 interface is often used up to 1 MBaud. The specified electrical characteristics allow a typical maximum cable length between transmitter and associated receiver of about 15 metres (50 feet). In practice, cable lengths can often be increased at lower rates and may need to be kept shorter at rates above 20 kBaud. RS-422 and RS-485 standards specify data signalling rates up to 10 MBaud, with decreasing cable length maxima at the higher rates. At the maximum signalling rate of the PC247H2-8H2 Series (1 MBaud), the maximum cable length is specified as 100 metres.

4.2.2.3 RS-232 Cable Adapters

Various plug-in adapter and test modules are available from Amplicon Liveline Ltd to ease the problems of interconnecting RS-232 interfaces. See www.amplicon.co.uk or the current catalogue for full details and descriptions.

4.3 RS-422/485 Application Notes

RS-422 and RS-485 have very similar characteristics, with RS-485 being compatible with, and offering all the advantages of RS-422 plus the additional capability of multi-transmitter operation, higher device capacity and better common mode performance. RS-422 pre-dated RS-485 as a standard, but RS-485 is now more popular and used in new system design. For the PC248H2(i), the on board circuitry for the two modes is identical, the application deciding the mode of interface operation.

4.3.1 RS-422/485 Parameters The following table summarises the principal parameters of the RS-422-B and RS-485 standards, and shows RS-232-C for comparison. The actual driver/receiver devices used in the PC247H2-8H2 Series at least meet these specifications, and provide superior performance in some cases.

PC247H2-8H2 Series

Page 32

EIA STANDARD RS-232-C RS-422-B RS-485 Mode of Operation Single ended Differential Differential

Number of Drivers and Receivers on line

1 Driver 1 Receiver

1 Driver 10 Receivers

32 Drivers 32 Receivers

Max. Cable Length 15 m 1200 m 1200 m Max. Data Rate 20 kBd 10 MBd 10 MBd

Max. Common Mode N/A +7 V, –7 V +12 V, –7 V Driver Voltage ±5 V to ±15 V ±2 V min ±1.5 V min

Driver Load 3 kΩ to 7 kΩ 100 Ω min 60 Ω min Driver Slew rate 30 V/µs N/A N/A Driver Output

Short Circuit Limit 500 mA to

Vcc or Ground 150 mA to

Ground 150 mA to Gnd 250 mA to Vcc

Receiver Input Resistance

3 kΩ to 7 kΩ 4 kΩ 12 kΩ

Receiver Sensitivity ±3 V ±200 mV ±200 mV Receiver Hysteresis 1.15 V 50 mV 50 mV

FIGURE 4.2 COMMUNICATIONS STANDARDS SUMMARY

4.3.2 RS-422/485 Signalling Sense

The RS-422 and RS-485 standards define the polarity of the signalling lines as follows.

"The signalling sense of the voltages appearing across the interconnecting cable is defined as follows:

a. The A terminal of the generator shall be negative with respect to the B terminal for a binary 1 (MARK or OFF) state

b. The A terminal of the generator shall be positive with respect to the B

terminal for a binary 0 (SPACE or ON) state" 4.3.3 RS-422/485 Multi-drop Applications

RS-422 can provide limited multi-drop capability, using two twisted wire pairs in a broadcast mode. One wire pair connects one transmitter to multiple receivers, but if duplex operation is required, only one receiving station can answer back. Figure 4.3 shows a typical RS-422 broadcast mode configuration with terminator resistors at the end receivers.

PC247H2-8H2 Series

Page 33

FIGURE 4.3 RS-422 CONNECTED IN BROADCAST MODE

RS-485 allows multiple (up to 32) transmitters and receivers to be connected in half duplex on a single twisted wire pair for 'party line' type of communications as illustrated in Figure 4.4. A method must be used to stop more than one transmitter being on the line at any time, ensuring that all other transmitters are in a high impedance state, although the circuit design is such that no damage will be done to the transceivers if several transmitters are turned on together. See chapter 5.3.7, ‘Half Duplex Transmission Turnaround’ for a discussion of the programming required for controlling the transmission direction.

FIGURE 4.4 RS-485 CONNECTED IN MULTI-DROP, HALF DUP LEX MODE

4.3.4 RS-422/485 Bus Termination For proper operation of the RS-422/485 bus in full or half duplex, multi-drop or point to point communication, it is recommended that termination is applied to the receiver end of the data and control lines. The simplest form of termination is line to line with typically a 120 Ω across the differential input, and this terminator is available on the PC248H2(i) boards, selectable by jumpers J62 for channel 1 and J82 for channel 2 as appropriate. In a multi-drop system, the terminator resistor is only required at the device receiver located at the far end of the cable. If this is in half duplex operation, then both ends of the bus cable are equipped with receivers (transceivers) so termination is necessary at both ends. RS-485 transmitter circuits are capable of driving a minimum load resistance of 60 Ω, so no more than two terminator resistors should be connected to any one bus.

Terminator Rx

Device 10 Device 2 Device 1

A B Tx

A' B' Rx

A' B' Rx

Terminator Rx

Resistor

PC248H² RS-422 Port

Rx - A Rx -

B Tx - A Tx - B

A' B' Rx

Terminator Rx

Device 32 Device 2 Device 1

A B Tx/Rx

A B Tx/Rx

Terminator Rx

Resistor

PC248H² RS-485 Port

Rx - A' Rx - B' Tx - A Tx - B

A B Tx/Rx

PC247H2-8H2 Series

Page 34

4.3.5 Cabling of RS-422/485 Bus The RS-422/485 employs a differential method of signal transmission, and each bus cable has to be a wire pair, preferably twisted and screened to keep induced and radiated noise to a minimum. The bus distribution cable is effectively a transmission line, and appropriate techniques should be used for installation of the cables. In a multi-drop environment, the cable should be 'looped through' each device, or if a spur is necessary, the spur length should be kept to a minimum. Maximum end-to-end cable length and the communication baud rate are not mutually exclusive. Typical maximum transmission rates versus cable lengths are shown in the following table. The data rates applicable to the PC248H2(i) are shown in bold type.

Transmission Rate Maximum Distance Up to 100 kBd 1200 m 115.3 kBd 1000 m 1000 kBd 100 m 10000 kBd 10 m

If screened cable is used, some thought must be given to the connection of the screen (shield). This screen should not normally be used as a ground return for non-isolated devices and it is safest to only connect the screen at a single point to the ground of one device. The voltage between the grounds of the various devices must not cause the common mode voltage rating of any device on the bus to be exceeded. The isolated PC248H2i must be used and the allowable common mode voltage range is considerably increased. If the installation instructions have been correctly followed, and the serial communications board is being used in conjunction with a proven software driver, then it is unlikely that any problems will be experienced in establishing communications through the serial interface. When difficulties do occur, the following notes may be helpful in isolating the problem area.

4.4 Testing and Troubleshooting The two channels of each board in the PC247H2-8H2(i) Series are largely independent, and testing of each channel can be undertaken separately. Ensure that each channel is correctly set up for channel base address, interrupt configuration and jumper positions before commencing the tests.

4.4.1 Testing with the Application Software

If either channel 1 or 2 appears to be working properly in the communication circuit and the other channel fails, then in many cases the two channels can be interchanged by re-assigning the base addresses for each channel and swapping the port connectors and the appropriate jumpers, including the IRQ levels. This can be done with the PC247H2(i) and the PC248H2(i) by simple re-plugging of the port connectors. After interchanging channels, if the same channel (1 or 2) fails, then the problem is on the board and service is necessary, and should be returned to Amplicon. See section 1.7 for details. If, after interchanging channels, the other channel of 1 or 2 fails, then the problem is outside the board, and the following areas should be investigated.

PC247H2-8H2 Series

Page 35

PC Bus contention. Ensure that register addresses or non-shareable IRQ levels do not clash with other board or in-built components of the host PC. If necessary inhibit any COMs channels that are built into the baseboard or multi-function plug-in boards. Communication circuits. For a communications circuit to operate correctly, both ends of the circuit, and the interconnecting cables must be serviceable and the correct connections made. The vagaries of RS-232 implementation often cause problems in making the proper connections, and the manufacturers instructions for the equipment at each end should be carefully checked. Hardware handshaking control signals. If the communication is operating under a software handshaking protocol (X-ON, X-OFF etc.) then only the transmitted and received data lines need to be connected. If the application requires hardware handshaking by the use of control lines CTS, RTS, DSR, DTR or DCD, then these must be correctly interconnected or looped back, otherwise the program is likely to hang . Polarity of RS-422/485 differential data lines. Not all suppliers use the same convention for the polarity of the differential data lines. The PC248H2(i) lines are labelled A and B for the transmitter and A' and B' for the receiver as defined in the RS-422/485 specification. If the other device is labelled differently, then:-

A is normally connected to A or A' or Y or High or + B is normally connected to B or B' or Z or Low or –

If all devices are not so labelled and the polarity is not evident, or if a problem is suspected in this area, then some experimentation may be necessary. No damage should be done to the interface hardware by reversing polarity.

4.4.2 Testing Using the Supplied Software

A test program is provided on the distribution diskette and this program allows operation of one channel of the board when the appropriate I/O connector is externally wired for loop back. In this diagnostic mode, data transmitted are immediately received on the same channel in full duplex operation. This allows the processor to verify the addressing, interrupt selection and the transmit and receive data paths of the selected serial channel.

4.4.2.1 The Loop Back Connections The required channel of the PC247/8H2 Series board can be separated from external influences such as the signal cables, other devices and the applications program by performing the following loop-back tests. For both RS-232 and RS-422/485 tests, it is necessary to make up a wrap connector using a 9 way D type free socket that mates with the port under test, and running the TEST_COM.EXE program supplied (see 4.4.2.2). The wrap connectors described can also be used for testing using other programs such as a terminal emulator or the user’s application program. Figure 4.5 shows the 9 way D connector wired for full RS-232 loop back testing. No connections need to be made to the ground pins, and the connections to be made are summarised as follows:

PC247H2-8H2 Series

Page 36

Signal Function 9 Way

From To Pin Pin TxD RxD 3 2 RTS CTS 7 8 DTR DSR and DCD 4 6 and 1

FIGURE 4.5 RS-232 9 WAY LOOP-BACK TEST CONNECTIONS Figure 4.6 shows the 9 way D connectors wired for full RS-422/485 loop back testing. The connections to be made are summarised in the following table. No connection needs to be made to the ground pin.

Signal Function 9 Way PC248 9 Way Standard 78 Way ( Chan 1) From To Pin Pin Pin Pin Pin Pin Tx-A Rx-A' 4 8 1 4 41 22 Tx-B Rx-B' 5 9 2 3 60 2 RTS-A CTS-A' 3 6 6 9 61 23 RTS-B CTS-B' 2 7 7 8 42 3

FIGURE 4.6 RS-422/485 LOOP-BACK TEST CONNECTIONS

9

8

GND RI DTR CTS

TxD RTS

RxD DSR

DCD

7

6

5

4

3

2

1

9

8

Tx-B Rx-B'

Tx-A Rx-A'

RTS-A CTS-B'

RTS-B CTS-A'

GND

7

6

5

4

3

2

1

THIS DIAGRAM REFERS TO THE AMPLICON STANDARD PINOUT (FIG 3.3). FOR ALTERNATIVE PIN ASSIGNMENTS

REFER TO FIGURE 3.4

PC247H2-8H2 Series

Page 37

Loop-back testing is only appropriate to full duplex operation and to test the RS-422/485 ports, the following jumper settings must also be checked.

Channel 1 Channel 2 Full Duplex J60 Out J80 Out Echo On J61 Out J81 Out Data Rx Terminator In J62 In J82 In

4.4.2.2 Loading and Using TEST_COM To use the supplied loop test program, first set up the board at the required base addresses and IRQ levels and modes required for the test. For RS-485/422 tests (PC248H2(i)), ensure that the jumpers for channel 1 or 2 are set as above. With the board properly installed, plug the appropriate wrap connector into the port. If any other compliant channels or adapters are attempting to use the same IRQ level as the channel under test, make sure that these are inactive. An interrupt from another source will cause this program to fail. Load the test program by logging onto the drive or directory containing the program and typing TEST_COM <return>. The program will load and the following screen will be displayed:

AMPLICON LIVELINE 200 Series Loopback Test Program -------------------------------------------------- Enter Channel Base Address : hex

Enter the same hex number for the base address that is set up on the corresponding channel of the board. This must be a valid address in the range 000 to 7F8 <return>. A non-valid entry will request re-entry of the address. The program will now request:

Enter Channel Interrupt Level : Enter the same number for the IRQ level that is set up on the corresponding channel of the board. This must be a valid value in the series 3, 4, 5, 7, 10, 11, 12 or 15 <return>. A non-valid entry will request re-entry of the interrupt level. The program will now request:

Enter Channel Baud Rate : 1. 1.2kBd 2. 9.6kBd 3. 19.2kBd 4. 112kBd (115.2) (1 - 4) :

Enter 1 to 4 to select the rate required for the test. If everything is correct, the program will run and display:

AMPLICON LIVELINE 200 Series Loopback Test Program -------------------------------------------------- XXX :

Y

PC247H2-8H2 Series

Page 38

where xxx is the selected base address and Y is a constantly changing ASCII character testing all normal code combinations. If there is a mismatch in the settings, or enough testing has been completed, the message:

Press a key to quit : followed by:

Press SPACEBAR to repeat, any other key to quit This allows the parameters to be re-entered. A mismatch of transmitted and received data causes a ‘bleep’ to be sounded, and although the program continues, the test should be terminated by pressing any key. The other channel of the board may now be tested in the same way.

4.4.3 Loop-back Testing Using A Terminal Emulator Windows 95/98/ME and NT/2000/XP come supplied as standard with a Terminal Emulation package called Hyper Terminal. This can be used for simple loop-back testing and is found in the Accessories section from the START button. The functionality of Hyper Terminal in Windows NT4/2000/XP can access up to COM256 if it is installed. Start Hyper-terminal and when prompted, enter a meaningful name such as Port 2 for COM2 or Port 4 for COM4 etc. The software will not let you use COM2 etc, as these are reserved words. At the 'Connect to' dialogue box, select 'Direct to COM n', where 'n' is the number of the COM port using the list box 'Connect using'. Then click 'OK'. Modify the port settings to your requirement if required, then click 'OK'. This will bring you to the main window and flashing cursor. Now, key presses will be echoed to the screen when the board and the loop-back connection is correctly made.

PC247H2-8H2 Series

Page 39

5 PROGRAMMING The PC247H2-8H2 Series are supplied with Windows 95, 98, ME, NT, 2000, and XP specific drivers.

5.1 Programming with Windows NT & 95 Device drivers . The distribution software provided with the PC247H2-8H2 Series board contains the Windows 95, 98, ME, NT, 2000, and XP device drivers. Application programmers writing programs to run under these operating systems will simply treat the port as a standard COMs port. All Programs written to run under these operating systems will be able to use the advanced features of the board. The special features such as ‘High Data Rate’, ‘128 Character FIFO’ and ‘Special Half Duplex mode (for RS-485 ports)’ are decided at installation and from then on controlled by the device driver.

5.1.1 Half Duplex Transmission Turnaround In a multiple RS-485 transmitter installation, the application program controls the data communication turnaround and the selection of the bus 'talker'. Two common ways of providing program control are the 'Master/Slave' and 'Token Ring' methods. The 'Master/Slave' method designates one device on the network as Master, and this device supervises all transmissions by communicating with each of the Slaves in turn and offering it a transmission slot. In token ring operation, each device knows its ID neighbour and only talks directly to this next device. Thus communication only occurs between adjacent pairs of devices and this makes for a flexible network but can be a more difficult method to implement. In half duplex mode the RS-485 transmit buffer is enabled automatically, by the 16C950 UART, whenever data is waiting to be sent in the UART Transmit buffer. This feature makes efficient multi-drop communication simple to implement by removing the burden of the Transmit buffer enable control from the software. Programmers may find this feature useful when trying to implement multi-drop systems using Application software that does not support control of the transmitter. The port can simply installed as a Special Half-Duplex port via the driver. The application software will then treat the port as it would any other. Transmit buffer enabling and disabling will then take place automatically. Special Half-Duplex mode requires the Windows driver supplied. Selection of this mode is by means of jumper links and device driver options. One interesting example of a case where the system engineer may easily take advantage of the advanced features of the board without resort to bespoke software design. Take the case of a SCADA system using an off the shelf SCADA type program set up to talk to COM3: RS-232 to a single external slave. If the user replaces COM3 with a PC248H2 board and installs the port as a Special Half Duplex RS-485 port using the device driver, the same software will then operate multi-drop half duplex RS-485 talking to a number of external slave devices. The RS-485 transmit buffer will be enabled when data is ready to be sent under control of the device driver. The PC247H2-8H2 Series board will often be used within an application specific program, and the user will integrate the serial communications operations into the bespoke program.

PC247H2-8H2 Series

Page 40

5.2 User Programming

5.2.1 Programming the UART Each UART serial channel is programmed by the control registers; Line Control Register (LCR), Interrupt Enable Register (IER), Divisor Latch Least significant Byte (DLL), Divisor Latch Most significant Byte (DLM), Modem Control Register (MCR) and FIFO Control Register (FCR). These control words define the character length, number of stop bits, parity, baud, and the modem interface. While the control registers can be written in any order, the IER should be written last because it controls the interrupt enables. Once the serial channel is programmed and operational, these registers can be updated any time that the channel is not transmitting or receiving data.

5.2.2 FIFO Interrupt Mode Operation The following receiver status will occur when the receiver FIFO and receiver interrupts are enabled. 1. LSR 0 is set when a character is transferred from the shift register to the receiver FIFO.

When the FIIFO is empty, it is reset. 2. IIR = 6 receiver line status interrupt has higher priority than the received data available

interrupt IIR = 4 3. Receive data available interrupt will be issued to the CPU when the programmed trigger

level is reached by the FIFO. As soon as the FIFO drops below the programmed trigger level, it will be cleared.

4. IIR = 4 (receive data available indication) also occurs when the FIFO reaches its trigger

level. It is cleared when the FIFO drops below the programmed trigger level. The following receiver FIFO character time-out status will occur when the receiver FIFO and receiver interrupts are enabled. 1. If the following conditions exist, a FIFO character time-out interrupt will occur

• Minimum of one character in the FIFO • Last received serial character was longer than 4 continuous previous character

times ago (If two stop bits are programmed, the second one is included in the time delay)

• The last CPU read of the FIFO was more than 4 continuous character times

earlier. At 300 baud and 12 bit characters, the FIFO time-out interrupt causes a latency of 160 ms maximum from received character to interrupt issued)

2. The time-out timer is reset after the CPU reads the receiver FIFO or after a new character

is received, when there has been no time-out interrupt. 3. A time-out interrupt is cleared and the timer is reset when the CPU reads a character from

the receiver FIFO. Transmit interrupts will occur as follows when the transmitter and transmit FIFO interrupts are enabled (FCR 0 = 1, IER 1 = 1)

PC247H2-8H2 Series

Page 41

1. When the transmitter FIFO is empty, the transmitter holding register interrupt (IIR=2) occurs. The interrupt is cleared as soon as the transmitter holding register is written to or the IIR is read. One to sixteen characters may be written to the transmit FIFO when servicing this interrupt.

2. The transmit FIFO empty indications will be delayed one character time minus the last

stop bit time whenever the following occurs:

THRE = 1 and there has not been a minimum of two bytes at the same time in the transmit FIFO since the last THRE = 1. The first transmitter interrupt after changing FCR 0 will be immediate however, assuming it is enabled.

Receiver FIFO trigger level and character time-out interrupts have the same priority as the received data available interrupt. The transmitter holding register empty interrupt has the same priority as the transmitter FIFO empty interrupt.

5.2.3 FIFO Polled Mode Operation Resetting IER 0, IER 1, IER 2, IER 3 all to zero, with FCR 0 = 1, puts the UART into the FIFO polled mode. The receiver and transmitter are controlled separately, therefore either one, or both, can be in the polled mode. In the FIFO polled mode, there is no time-out condition indicated or trigger level reached. However, the receiver and transmitter FIFOs still have the capability of holding characters. The Line Status Register (LSR) must be read to determine the UART status.

5.2.4 Interrupt Operations The interrupt operations comply with the requirements laid down in the Industry Standard Architecture (ISA) for the Personal Computer Bus. The interrupt request line, IRQ 3-5, IRQ7, IRQ10-12 or IRQ15, signals the host PC (Permanent Master) that the PC247H2-8H2 Series adapter requires service. The host PC processor acknowledges the interrupt and takes the required action with the appropriate service routine.

5.2.5 Non-shared Interrupts When enabled, non-shared interrupts allow only one device to use an interrupt request line at any one time. When the interrupts are turned ON, the serial port currently using IRQn drives it to a LOW state. The port generates an interrupt by turning the driver into its high impedance state allowing it to be pulled to a HIGH level by a resistive pull up on the host PC. IRQn remains at a HIGH state until the interrupt is acknowledged by the appropriate write or read. When the serial board port does not require interrupt service, the user should ensure that its active interrupt drive is removed, allowing the use of the IRQn line by another port or adapter. The IRQn can be put into its high impedance state by disabling all interrupts using bit 3 of the Modem Control Register (UART MCR).In non shared mode the board will not operate on an interrupt level assigned to any other device. Careful checking of interrupt assignment in your system is recommended prior to board installation. The board will not normally operate on interrupt levels 3 & 4, i.e. the normal interrupts assigned to COM3 & COM4, if COM1 and COM2 are present in the PC. This is because COM1 & COM2 use interrupt levels 4 & 3 respectively and most standard communications cards do not support shared interrupts.

PC247H2-8H2 Series

Page 42

5.2.6 Shared Interrupts

Interrupts may only be shared with other devices that support shared interrupts. Shared interrupts allow more than one device to use a common interrupt request line. The shared interrupt concept requires that the interrupting channel indicates the need for service by a pulse rather than a level. Each port of the serial communications board has an interrupt status latch that is set before an interrupt is initiated. The processor starts an interrupt sequence by arming the PC interrupt controller on the leading edge of a negative pulse (125 to 1000 ns) occurring on the interrupt request line. The trailing edge signals the interrupt controller to cause the interrupt. Each properly configured, interrupt-sharing adapter on a common interrupt level monitors the allocated IRQ line. When any adapter, including the PC247H2-8H2 Series board, pulses the line, no other adapter will issue an interrupt until it is re-armed. The interrupt status latch is reset, and the interrupt level re-enabled, by the interrupt service routine issuing a global re-arm by writing to the appropriate port. Further information on handling shared interrupts is given in 5.3.6.1 below and the details can be found in an IBM Technical Reference Manual or other advanced reference documentation relating to the host PC.

5.2.6.1 Shared Interrupts Programming Hints The following information may be useful to a programmer incorporating code into an applications program. Full interrupt sharing program support must provide an orderly means to:

Link a task's interrupt handler to a chain of interrupt handlers Share the interrupt level while the task is active Unlink the interrupt handler from the chain when the task is de-activated Simpler support for shared interrupts in a single application such as serial communications may not require the chain linking/unlinking.

Linking onto the Chain Each newly activated task replaces the interrupt vector in low memory with a pointer to its own interrupt handler. The old interrupt vector is used as a forward pointer and is stored away at a fixed offset from the new task's interrupt handler. This method of linking means the last handler to link is the first one in the chain.

PC247H2-8H2 Series

Page 43

Sharing the Interrupt Level When the new task's handler gains control as a result of an interrupt, the handler reads the contents of the adapter’s interrupt status register to determine if its adapter caused the interrupt. If its adapter did cause the interrupt, the handler services the interrupt, disables the interrupts (CLI) and writes to address 02Fx or 06Fy where x corresponds to the interrupt levels 2 through 7 and y corresponds to the interrupt levels 10 through 15. Each adapter in the chain decodes the address, which results in a Global Rearm. The handler then issues a non-specific End Of Interrupt (EOI) and finally issues a Return From Interrupt (IRET). If its adapter did not cause the interrupt, the handler passes control to the next interrupt handler in the chain. Unlinking from the Chain To unlink from the chain, a task must first locate its handler's position within the chain. By starting at the interrupt vector in low memory and using the offset of each handler's forward pointer to find the entry point of each handler, the chain can be methodically searched until the task finds its own handler. The forward pointer of the previous handler in the chain is replaced by the task's pointer, removing the handler from the chain. If the handler cannot locate its position in the chain or the signature of any prior handler is not as defined, it must not unlink. Error Recovery If the unlinking routine discovers that the interrupt chain has been corrupted, an unlinking error recovery procedure must be in place. Each application can incorporate its own unlinking error procedure into the unlinking routine. The procedure may choose to display an error message requiring the operator to intervene, but the application must not unlink. Further Precautions • The programmer must ensure that a short routine is incorporated that can be executed with

the AUTOEXEC.BAT to disable the adapter’s interrupts. This precaution ensures that the adapters are deactivated for a system reboot that does not clear memory.

• Words must be treated as words, not bytes. • The data word is stored in memory using the INTEL format. Word 424B(hex) is stored as

4B42(hex). NOTE Examples of code for the interrupt handler, chaining, linking and unlinking are given in some versions of the IBM Technical Reference Handbook. Amplicon Liveline cannot assist with writing user code for shared interrupts.

5.2.7 Half Duplex Transmission Turnaround In a multiple RS-485 transmitter installation, the application program controls the data communication turnaround and the selection of the bus 'talker'. Two common ways of providing program control are the 'Master/Slave' and 'Token Ring' methods. The 'Master/Slave' method designates one device on the network as Master, and this device supervises all transmissions by communicating with each of the Slaves in turn and offering it a transmission slot. In token ring operation, each device knows its ID neighbour and only talks directly to this next device. Thus communication only occurs between adjacent pairs of devices and this makes for a flexible network but can be a more difficult method to implement.

PC247H2-8H2 Series

Page 44

The PC248H2(i) provides two methods of communication turnaround. One of them is by enabling the 'ON' transmitter using the RTS output line of the relevant UART. This active low is inverted and must be set to enable the transmitter. For full duplex operation of RS-422/485 a jumper ensures that the transmitter is permanently enabled. An example of programming the RTS bit to effect communication turnaround is given in the following BASIC program fragment. RTS is bit MCR 1 of the Modem Control Register which is found at the channel base address BA+04. The default logic '1' at /RTS sets the transceiver to receive and the active logic '0' sets it to transmit.

regs=inp(BA+4) 'Input register contents regs=regs OR &H02 'Set bit 2 for transmit regs=regs XOR &H02 'Reset bit 2 for receive out(BA+4),regs 'Output to modem register

When the RTS signal is being used for transmission control, the RTS output is still available on the I/O connector and can be externally linked to return the signal on the CTS input lines. See paragraph 3.6 and Figure 3.5 for the connections required. CTS can now be monitored on bit 4 of the Modem Status Register to determine the instantaneous state of the transmission direction. The other method of Transmitter turnaround is Special Half Duplex mode, mentioned already in section 1.4.1. In this mode the RS-485 transmit buffer is enabled automatically, by the 16C950 UART, whenever data is waiting to be sent in the UART Transmit buffer. This feature makes efficient multidrop communication simple to implement by removing the burden of the Transmit buffer enable control from the software. Programmers may find this feature useful when trying to implement multidrop systems using Application software that does not support control of the transmitter. The port can simply installed as a Special Half Duplex port via the driver. The application software will then treat the port as it would any other. Transmit buffer enabling and disabling will then take place automatically. Special Half Duplex mode requires the Windows driver supplied. Selection of this mode is by means of jumper links and device driver options.

PC247H2-8H2 Series

Page 45

APPENDIX A TECHNICAL SPECIFICATIONS

Figures given in the specification are typical at 2 5° C, except where otherwise stated.

APP A1 HARDWARE SPECIFICATION

APP A1.1 FUNCTION The PC247H2I and the PC248H2i provide a range of Serial

Communications Boards with the serial data and control lines electrically isolated from the confines of the host PC. The PC247H2 and the PC248H2 provide a similar range of boards without the isolation feature. The products are part of the 200 Series and conform with the general requirements of this range.

The six boards in the range each provide two independent

serial communications interfaces, but differ in their support of the standards:

PC247H2 and PC247H 2i Channel 1 (Upper) Channel 2 (Lower) Communications RS-232 RS-232 I/O Connector 9 way male D 9 way male D PC248H2 and PC248H 2i Channel 1 (Upper) Channel 2 (Lower) Communications RS-422/485 RS-422/485 I/O Connector 9 way male D 9 way male D

APP A1.2 RS-232 PORT APP A1.2.1 9 way Connector Used on PC247H2 and PC247H2i channel 2 lower RS-232 port. 9 way, male D connector with metal shell. Pinouts to IBM

input/output standard. For the isolated versions, all signals are referred to the remote device signal ground. The connector shell is connected to the local PC chassis ground.

APP A1.2.2 Configuration PC247H2 and the PC247H2i RS-232 ports are configured as

Data Terminal Equipment (DTE) APP A1.2.3 Rx Voltage Levels RS-232 receivers - RXD, DCD, DSR, CTS and RI

Min Typ Max Input threshold low (V) 0.8 1.3 Input threshold high (V) 1.7 2.4 Input hysteresis (V) 0.1 0.4 1.0

PC247H2-8H2 Series

Page 46

Input resistance (kΩ) 3 5 7 APP A1.2.4 Tx Voltage Levels RS-232 drivers - TxD, DTR and RTS Min Typ Max Output voltage swing Pos (V) +5.0 +7.3 (Loaded 3 kΩ to Gnd) Neg (V) –6.5 –5.0 Output short circuit current (mA) ±17 APP A1.2.5 Data Rate The standard driver allows error free data transmission at rates

up to 120 kBaud. The board is capable of data rates up to 1 MBaud but these rates require special software, such as the Windows 95, 98, ME, NT, 2000, XP, or Linux device drivers available from Amplicon.

APP A1.2.6 I/O Isolation For the isolated versions, each RS-232 interface is electrically

isolated from the host PC circuit, with no common connections to the other port. Signal isolation is by opto-couplers on the data and control lines and power to the drivers/receivers is supplied through an isolated DC-DC converter.

Isolation specifications measured between Reference Signal

Ground of the external device and Chassis Ground of the host PC are:-

Maximum test voltage ±400 Vpk Maximum user applied voltage (Short duration) ±250 Vpk Maximum user applied voltage DC (Sustained) ±75 VDC Maximum user applied voltage AC (Sustained) 50 VAC Typical on-board common mode Impedance 1 MΩ in parallel with 1 nF APP A1.2.7 I/O Protection Driver outputs and receiver inputs can be shorted beyond the

RS-232 fault limits to ±30 V without damage.

PC247H2-8H2 Series

Page 47

APP A1.2.8 ESD Protection The RS-232 line input/outputs have on-chip protection from

ESD transients up to ±8 kV for human body model discharges.

APP A1.3 RS-422/485 PORT APP A1.3.1 9 way Connector Used on PC248/PC248H2i channel 1 upper and channel 2 lower

ports. 9 way, male D connector with metal shell. For the isolated

versions, all signals are referred to the remote device signal ground. The connector shell is connected to the local PC chassis ground.

APP A1.3.2 Rx Voltage Levels RS-422/485 receiver - RXD and CTS Min Typ Max Differential threshold voltage (V) –0.2 0.2 (–7 ≤ Vcm ≤ 12 V) Receiver input hysteresis (mV) 70 (Vcm = 0 V) Receiver input resistance (kΩ) 12 (–7 ≤ Vcm ≤ 12 V) APP A1.3.3 Rx I/P Termination 120 Ω resistor across differential input terminals of both Rx

Data and CTS receivers. For multi-drop applications, the Rx data line termination resistor can be disconnected by removing a jumper.

APP A1.3.4 Tx Voltage Levels RS-422/485 driver - TXD and RTS Min Typ Max Differential driver output (no load) 5 V Differential driver output (with load) Load = 50 Ω (RS-422) 2 V Load = 27 Ω (RS-485) 1.5 V 5 V Driver common mode output voltage 3 V Differential output load resistance 27 Ω APP A1.3.5 Tx O/P Protection Excessive output current and power dissipation caused by

faults or bus contention are prevented by two mechanisms. A fold-back current limit provides immediate protection against short circuits and thermal protection forces the driver into a high impedance state if the die temperature exceeds the limits.

PC247H2-8H2 Series

Page 48

APP A1.3.6 I/O Isolation Each RS-422/485 interface is isolated to the same specification

as the RS-232 interface in A1.2.7 APP A1.3.7 Slew Rate Limitation The RS-422/485 driver outputs have on-chip slew rate limitation

for improved EMC and reduced reflections. This reduced slew rate allows error free data transmission at rates up to 250 kbps.

APP A1.3.8 ESD Protection The RS-422/485 line input/outputs have on-chip protection from

ESD transients up to ±8 kV for human body model discharges.

APP A1.4 MODES Full Duplex, Half Duplex, Special Half Duplex, Multi-drop,

Broadcast APP A1.4.1 Transmit Turnaround Transmission turnaround by the RTS control line is used in

RS-485 half duplex operation.

When the /RTS line of the UART is low (active), the RS-485 transmission is enabled. When /RTS is high (inactive), RS-485 reception is enabled. Default condition is reception enabled.

Activation of /RTS is under control of the control of software as

a default. The UART also allows for hardware control of /RTS. In this mode /RTS is activated when data is present in the transmit buffer. Selection of hardware control of /RTS requires special software, such as the Windows 95, 98, ME, NT, 2000, XP, or Linux device drivers available from Amplicon.

By external loop-back of the RTS-CTS differential lines, the

instantaneous status of the control signal can be monitored.

PC247H2-8H2 Series

Page 49

APP A1.5 UARTS Two 16C950 Universal Asynchronous Receiver-Transmitter

(UART) with FIFOs. The UARTs default to the condition where all registers are similar to the 16C550.

APP A1.5.1 Baud Rates There are two link selectable (J4) crystal oscillator modules.

OSC1 operates at a frequency of 1.8432 MHz to produce programmable baud in the range 50 Baud to 112 kBaud. OSC2 operates at a frequency of 40 MHz to produce programmable baud up to 1MBaud. OSC1 is the default and works with all standard software. OSC2 and the faster baud require special software, such as the Windows 95, 98, ME, NT, 2000, XP, or Linux device drivers.

APP A1.5.2 Data Bits Programmable 5, 6, 7 or 8. APP A1.5.3 Stop Bits Programmable 1 or 2 APP A1.5.4 Parity Programmable Even, Odd or None

APP A1.6 INTERRUPTS When the interrupts are enabled, each channel generates an

interrupt request whenever a receiver error, receiver data available, transmitter empty or modem status condition flag is detected.

APP A1.6.1 Interrupt Levels The interrupt signal from each channel can be assigned to one

of eight mutually inclusive IRQ levels. These levels are IRQ 3-5, IRQ7, IRQ10-12 and IRQ15. The required level for each channel is selected by three poles of an in-line switch (SW3).

APP A1.6.2 Shared Interrupts Each channel can individually use shared or non-shared

interrupts, selected by a single pole of the in-line switch (SW3). Shared and non-shared interrupts comply with the ISA standard. Interrupts may only be shared with other devices that support shared interrupts.

In non shared mode the board will not operate on an interrupt level assigned to any other device. Careful checking of interrupt assignment in your system is recommended prior to board installation.

The board will not normally operate on interrupt levels 3 & 4, i.e. the normal interrupts assigned to COM3 & COM4, if COM1 and COM2 are present in the PC. This is because COM1 & COM2 use interrupt levels 4 & 3 respectively and most standard communications boards do not support shared interrupts.

PC247H2-8H2 Series

Page 50

APP A1.6.3 Interrupt Control Interrupts can be individually masked by bits 0-3 of the UART

Interrupt Enable Register. All interrupts can be globally enabled/disabled by bit 3 of the UART Modem Control Register.

In non-shared operation, globally disabling the interrupts

ensures that the selected IRQ line is forced to its high impedance state so freeing the line for use by other adapters. This feature maintains compatibility with the interrupt control feature of the earlier PC47/8/9AT boards.

APP A1.7 POWER-UP DEFAULT Under RESET conditions, the UART emulates the 16C550

APP A1.8 PC INTERFACE Compatibility 8 bit XT or 16 bit AT bus. Single half length slot. Only 4 IRQ

levels available on XT bus Base Address Each channel discrete base address individually set by 8 pole

in-line switch. Upper Channel 000 to 7F816, at any 8 bit boundary. Lower Channel 000 to 7F816, at any 8 bit boundary. Registers occupy 8 contiguous locations above each base

address. Default settings of the port base addresses to be: Channel 1(Upper) Base address COM3: 3E816 Channel 2 (Lower) Base address COM4: 2E816 Interrupt Levels IRQ 3, 4, 5 and 7 on PC I/O Bus Connector PLB IRQ 10, 11, 12 and 15 on I/O Bus Connector PLD Default settings of the interrupt levels to be: Channel 1 (Upper) IRQ 4 Channel 2 (Lower) IRQ 3 Power Requirements +5 VDC from PC I/O bus. Current required from +5 V PC

supply: All Tx Data lines fully loaded. PC247H2(i) 0.45 A typical operating PC248H2(i) 0.5 A typical operating Multiple Boards Any number of the specified boards in any combination,

commensurate with physical space, I/O address space and power availability can be supported in a single PC.

PC247H2-8H2 Series

Page 51

APP A2 SOFTWARE The distribution software is supplied on a 31/2 inch high density

diskette.

TEST_COM.EXE provides a simple user test program that requires wiring the data and control lines for external loop-back diagnostic testing.

This program operates on a single channel and allows selection

of the communications data rate, the channel base address and the interrupt level.

Windows 95, 98, ME, NT, 2000, and XP Driver Software

provides Application level access to all the advanced features of the board from these operating systems.

PC247H2-8H2 Series

Page 52

APP A3 ENVIRONMENTAL CONDITIONS

APP A3.1 ENVIRONMENT All boards in the PC247H2-8H2 Series are designed to operate in a PC/AT environment

APP A3.2 SPECIFIC CONDITIONS

I/O Positions Required One half length I/O slot with 8 or 16 bit XT or AT bus connector. Board Dimensions Length ≈157 mm (Minimum length) Height ≈99 mm plus edge connectors. Temperature Range Operating 0° C to +60° C Storage –20 to +70° C Power Requirements +5 VDC at up to 600 mA maximum from host PC power supply. Dissipation Each board will dissipate less than 1.6 Watts of heat. Handling Normal static handling precautions apply. Damage could result

if not observed

APP A3.3 ELECTRO MAGNETIC COMPATIBILITY All boards in the PC247H2-8H2 Series comply with the European directive 89/336/EEC

(89/336/EEC) Electro-Magnetic Compatibility

PC247H2-8H2 Series

Page 53

APPENDIX B LAYOUT AND CIRCUIT DIAGRAMS Layout and circuit diagrams are given in this appendix to cover all variations of the PC247H2(i) and the PC248H2(i).

APP B1 Layout Diagrams

Figures B.1 and B.2 provide layout diagrams for the PC247H2(i) and the PC248H2(i) respectively. These layout diagrams show all the components for the isolated versions. The non-isolated versions have printed circuit links retained across the drill points and do not have the components fitted: PC247H2 PC248H2

Channel 1 Channel 2 Channel 1 Channel 2 U19 U31 U19 U31 U11 U23 U11 U23 U12 U24 U12 U24 U13 U25 U13 U25 U14 U26 U14 U26 U15 U27 U15 U27 U16 U28 U16 U28 U17 U29 U17 U29 U18 U30 U18 U30 U20 U32 U10 U22 U21 U33 R3 R29 R3 R29 R4 R30 R4 R30 R5 R31 R5 R31 R6 R32 R6 R32 R7 R33 R7 R33 R8 R34 R8 R34 R9 R35 R9 R35 R10 R36 R10 R36 R11 R37 R11 R37 R12 R38 R12 R38 R13 R39 R13 R39 R14 R40 R14 R40 R15 R41 R15 R41 R16 R42 R16 R42 R17 R43 R17 R43 R18 R44 R18 R44 R25 R51 R25 R51 C19 C28 C19 C28 C20 C29 C20 C29 C21 C30 C21 C30 C30 C31 C30 C31 J60 J80 J61 J81 J62 J82

PC247H2-8H2 Series

Page 54

PC247H2-8H2 Series

Page 55

APP B2 PC247H 2(i) Circuit and Layout Diagrams Figure B.4 shows the circuit diagram of the dual channel RS-232 input/output circuits and Figure B.1 below shows the layout of the PC247H2(i). The devices required for isolation are indicated by bold typeface in the list below, and these components are not fitted to the PC247H2 (non-isolated). The principal devices and their functions are identified in the following list:- Device Type Function U11/23 HCPL0600 Opto-coupler for Channel 1/2 ‘Received Data’ line to the UART.

U12/24 HCPL0600 Opto-coupler for Channel 1/2 ‘Transmit Data’ line to the UART.

U13/25 HCPL0600 Opto-coupler for Channel 1/2 ‘DSR’ line to the UART.

U14/26 HCPL0600 Opto-coupler for Channel 1/2 ‘DTR’ line to the UART.

U15/27 HCPL0600 Opto-coupler for Channel 1/2 ‘CTS’ line to the UART.

U16/28 HCPL0600 Opto-coupler for Channel 1/2 ‘RTS’ line to the UART.

U17/29 HCPL0600 Opto-coupler for Channel 1/2 ‘RI’ line to the UART.

U18/30 HCPL0600 Opto-coupler for Channel 1/2 ‘DCD’ line to the UART.

U10/22 MAX3245 RS-232 Driver/receiver for Channel 1/2 control, and data lines.

U19/31 SI-0505ND DC-DC Converters for supplying power to Channel 1/2 isolated circuits

PL60 9 way male D connector for Channel 1 RS-232 input/output

PL80 9 way male D connector for Channel 2 RS-232 input/output

FIGURE B.1 PC247H2I LAYOUT DIAGRAM

PC247H2-8H2 Series

Page 56

APP B3 PC248H 2(i) Circuit and Layout Diagrams Figure B.5 shows the circuit diagram of the dual channel RS-422/485 input/output circuits and Figure B.2 below shows the layout of the PC248H2(i). The devices required for isolation are indicated by bold typeface in the list below, and these components are not fitted to the PC248H2 (non-isolated). The principal devices and their functions are identified in the following list:- Device Type Function U11/23 HCPL0600 Opto-coupler for Channel 1/2 ‘Received Data’ line to the UART.

U12/24 HCPL0600 Opto-coupler for Channel 1/2 ‘Transmit Data’ line to the UART.

U14/26 HCPL0600 Opto-coupler for Channel 1/2 ‘DTR’ line to the UART.

U15/27 HCPL0600 Opto-coupler for Channel 1/2 ‘CTS’ line to the UART.

U16/28 HCPL0600 Opto-coupler for Channel 1/2 ‘RTS’ line to the UART.

U20,21

/U32,33

MAX491/3086 RS-485 Driver/receivers for Channel 1/2 control, and data lines.

U19/31 SI-0505ND DC-DC Converters for supplying power to Channel 1/2 isolated circuits

PL60 9 way male D connector for Channel 1 RS-422/485 input/output

PL80 9 way male D connector for Channel 2 RS-422/485 input/output

FIGURE B.2 PC248H2I LAYOUT DIAGRAM

PC247H2-8H2 Series

Page 57

APP B4 Circuit Diagram PC247H 2-8H2(i) - All Versions Figure B.3 shows the circuit of the section that is common to all versions of the PC247H2-8H2(i) boards. This circuit diagram includes the PC interface and dual UART. The principal devices and their functions are listed below:- Device Type Function U9/U34 16C950 UART Universal Asynchronous Receiver-Transmitter. Performs

the parallel/serial and serial/parallel conversion of data received from the PC on transmission and the external lines on reception. Status registers indicate error conditions and transfer operations. Internal FIFOs store up to 128 bytes each of transmitted or received data.

U1 EPM7064 PAL Interrupt handling, shared interrupt latches. Global re-arm

signal generation and chip select signal generation. U7 74HCT688 Comparator Global re-arm address decoder U5 74HCT688 Comparator Channel 1 base address decoder U6 74HCT688 Comparator Channel 2 base address decoder U2 74HCT240 Tri-state Buffers PC address line buffers U4 74HCT245 Tri-state Tx/Rx PC data I/O transceiver buffers OSC1 1.8432 MHz Oscillator Provides accurate, stable crystal oscillator source for the

DUART baud rate generators in PC247-9 compatible mode.

OSC2 40 MHz Oscillator Provides accurate, stable crystal oscillator source for the

DUART baud rate generators when UART is operating at higher data rates under advanced options.

SW1 Eight pole DIL Switch Channel base address switch for channel 1 (upper) SW2 Eight pole DIL Switch Channel base address switch for channel 2 (lower) SW3 Eight pole DIL Switch Interrupt level selection switch for both channels.

PC247H2-8H2 Series

Page 58

APP B5 USER’S NOTES - DRAWINGS

PC247H2-8H2 Series

Page 59

PC247H2-8H2 Series

Page 60

FIGURE B.3 PC247H2-8H2 CIRCUIT SCHEMATIC PC INTERFACE AND UARTS

FIGURE B.4 PC247H2(I) CIRCUIT SCHEMATIC DUAL CHANNEL RS-232 I/O

PC247H2-8H2 Series

Page 61

FIGURE B.5 PC248H2(I) CIRCUIT SCHEMATIC DUAL CHANNEL RS-422/485 I/O