ADLINK cPCI-3544/3534/3538 Serial Cardcard Configuration Practice



ADLINK cPCI-3544/3534/3538 Multi Port Serial Port Module Integration and Driver Practical Guide

In industrial grade CompactPCI systems, multi serial port expansion is a common requirement for connecting PLCs, smart meters, data acquisition terminals, and modems. ADLINK's cPCI-3534 (3 x RS-232+1 x isolated RS-422/485), cPCI-3544 (4 x isolated RS-422/485), and cPCI-3538 (8 x RS-232) serial communication modules are widely used in transportation, power, military engineering, and other fields due to their 16C550 compatible controller, maximum 115.2kbps speed, and PCI plug and play features. However, the switch settings, terminal resistance matching, isolation grounding, and driver installation under different operating systems are often difficult points in engineering debugging when multiple cards coexist. This article is based on the original factory technical manual, providing a practical technical reference for on-site engineers from hardware configuration, multi card recognition, driver deployment to troubleshooting.

Product Series Overview and Selection Decision

All three modules adopt 3U cPCI specifications (160 × 100mm), 32-bit PCI 2.1 bus, and support shared IRQ and automatic allocation of I/O addresses. The difference lies in:

CPCI-3534: 3 standard RS-232 ports (complete 9-wire system, including hardware flow control) and 1 isolated RS-422/485 port (isolated voltage 2500VDC) that can be switched between software and dial-up. Suitable for scenarios where a small number of RS-232 devices are paired with a long-distance differential communication channel.

CPCI-3544: 4 fully isolated RS-422/485 ports, each channel is independently isolated (500VDC), supports RS-485 automatic direction control, and can install up to 8 cards (32 ports), making it an ideal choice for pure differential multi node bus applications.

CPCI-3538: 8 standard RS-232 ports, without onboard isolation, but can independently select isolated RS-232/422/485 for each port through an external C888XB expansion box. Suitable for high-density standard serial port connection.

Selection key: If multiple frequency converters or intelligent sensors are needed on site to form an RS-485 network, and each device is dispersed in different potential areas, cPCI-3544 is preferred; If only one isolation differential port is needed and an RS-232 debugging port is required, select cPCI-3534; If all are RS-232 and require more than 4 ports, cPCI-3538 has the highest cost-effectiveness.

Hardware interface and wiring specifications

1. Connectors and cables

CPCI-3534/3544: The front panel has a DB37 female connector, which is connected to four ports through branch cables (C425M with four DB25 male connectors, or C409M with four DB9 male connectors).

CPCI-3538: The front panel is a DB62 female head, which outputs 8 ports through C825M (8 × DB25) or C809M (8 × DB9) cables.

All cables have shielding layers, and it is recommended to ground them at one end to reduce common mode interference.

2. Key points of pin definition

RS-232 port (A/B/C of 3534, all 3538): standard TXD, RXD, RTS, CTS, DSR, DTR, DCD, RI, GND, supports hardware flow control. When connecting DTE devices (such as computers), cross connect TXD/RXD, and connect DCE devices (such as modems) with straight through lines.

Differential ports (Port D of 3534, all of 3544):

RS-422 full duplex: TXD+/- connected to each other RXD+/-, RXD+/- connected to each other TXD+/-.

RS-485 half duplex: D+is connected to D+, D - is connected to D -, and all nodes are connected to the same bus.

Each port of 3544 has an independent isolated ground (GND), which must be connected to the signal ground of external devices, but cannot be mixed with the system digital ground (GND), otherwise it will damage the isolation performance.

Terminal resistance: JP1 (RS-422) and JP2 (RS-485) of 3534 are jumper caps, and a short circuit activates the 120 Ω terminal; 3544 Each port corresponds to two sets of jumpers (such as JP1/JP2 for Port A, JP3/JP4 for Port B, etc.). Proper configuration of terminal resistors is crucial for the stability of long-distance communication, and only devices at both ends of the bus should be enabled.

Coexistence of multiple cards and card number configuration

Due to the automatic allocation of resources by the PCI bus, but the COM port number needs to be fixed, each module distinguishes the card order through hardware switches.

1. cPCI-3534/3538 (up to 2 cards)

The onboard SW1-1 (3534) or JP1 (3538) serves as the "first card/second card" selector. ON indicates that the card is the first card in the system, and OFF indicates the second card.

The first card is assigned a lower COM port number (such as COM3~COM6), while the second card is assigned a higher COM port number (such as COM7~COM10).

It is strictly prohibited to turn on or off two cards at the same time, otherwise the system cannot distinguish and may cause unknown devices or port numbers to appear in the device manager incorrectly.

2. cPCI-3544 (up to 8 cards)

Set the binary card number (0-7) using the SW1-3 three digit dip switch. The uniqueness of the card number determines the order of port enumeration.

For example, when SW1-3 is set to 0, 1, 2..., they correspond to different cards, and port numbers are assigned in ascending order of card number.

After setting the card number, even if the PCI slot is changed, the port number remains unchanged for easy on-site maintenance.

3. Suggestions for the installation sequence of multiple cards

In Windows NT/2000/XP, it is recommended to install the first card (ON or card number 0) first, load the driver, and then install the second card, and so on, to avoid resource conflicts. Before installation, it is necessary to ensure that the system has at least one idle IRQ for PCI PnP allocation.

Isolation and grounding strategy

Port D isolation of cPCI-3534: The voltage withstand between the isolated ground (GND) and the system ground (GND) is 2500VDC. When wiring, the reference ground of external devices must be connected to this isolated ground, not GND, otherwise the isolation will fail and the optocoupler may be damaged.

Channel isolation of cPCI-3544: Each port has an independent isolation ground, and all four ports and ports to the system are isolated (500VDC). This design allows different ports to connect devices at different ground potentials, completely eliminating ground loop interference.

RS-485 bus grounding: Although isolated, in order to ensure that the common mode voltage does not exceed the isolation range, it is recommended to connect the isolated ground on the bus to the system earth ground at a single point, providing a discharge path.

Deep Analysis of Operating System Driver Installation

1. Windows NT 4.0

Go to "Control Panel ->Network ->Add Adapter", select "Install from Disk", the paths are:

3534/3538: X:  NuCOM  CCPI3534  NT4 or CPCI3538  NT4

3544：X:NuCOMCPCI3544NT4

During the installation process, specify the starting COM number (default COM3), and the system will arrange the first card port starting from this number.

Multi card rule: The first card (SW1-1=ON) has consecutive port numbers, and the second card (OFF) has a port number immediately following the end of the first card.

If you have previously installed an old driver, you must uninstall it before installing the new version, otherwise there may be a blue screen due to residual drivers.

2. Windows 95/98 (plug and play)

The system automatically discovers new hardware, simply follow the wizard to specify the driver path.

Due to the inability to reverse the card sequence through resources, it is entirely dependent on the ON/OFF of SW1-1/JP1 to distinguish between the first and second cards. Therefore, it is necessary to set the first card to ON and the second card to OFF.

After installation, the system will automatically add COM ports without the need for a restart (in some cases).

3. Windows 2000/XP (preferred for stability)

After plug and play hardware discovery, specify the driver directory:

3534/3538：X:SerialCommcPCI-353XWin2000-XP

3544：X:SerialCommcPCI-3544W2000

Similarly, the jumpers 3534/3538 determine the first/second card, while 3544 determines the enumeration order through the SW1-3 card number. This mechanism ensures the certainty of port numbers, which is particularly important for industrial software.

4. Linux environment

3534/3538：

Extract alnxsrc. Z, create a floppy disk image using dd, and extract tar to/etc/rayon.

Execution /Install， Select the card type according to the menu.

Ensure that the kernel source code path is/usr/src/Linux, otherwise compilation will fail.

3544：

Extract pci3544.tgz and enter the drivers directory.

Execute the installation script /3544-in. pl cards N (N is the actual number of cards), can specify TTY master device number and Callout master device number (default 70/71).

The script automatically detects 3544 devices on the PCI bus and creates device nodes (/dev/ttySx and/dev/cuix), after which standard serial port APIs can be used for programming.

5. RS-422/485 mode settings for cPCI-3544 (Windows)

3534/3538 does not require configuration, but 3544 requires selecting RS-422 or RS-485 mode for each port through the included AdlComSet.exe tool. When RS-422 is selected, the RS-485 function of the corresponding port is automatically disabled; When RS-485 is selected, automatic direction control (hardware automatic switching of transmission and reception) is automatically enabled without software intervention in RTS.

Common troubleshooting and countermeasures

Possible causes and solutions for the fault phenomenon

The system cannot recognize the poor contact of the cPCI slot on the new card or insufficient power supply on the backplane. Re plug and unplug, check the power supply of the chassis; Replace slot position

Multiple card switch status conflicts (3534/3538) or card numbers are duplicated (3544) in the device manager. Check all cards' SW1-1/JP1 to ensure one is ON and one is OFF; 3544 Check if the SW1-3 card number is unique

Serial port sending is normal, but receiving garbled baud rate/parity does not match; Terminal resistor configuration error check communication parameters at both ends; Check if the RS-422/485 terminal jumper is enabled as needed

RS-485 can only send but cannot receive direction control is not effective (3534 requires software control of RTS) 3534 needs to correctly raise/lower RTS in the program; 3544 confirms that it has been set to RS-485 mode (automatic control)

The isolated port has no signal or sparks on the ground wire. The ground wire of the isolated device is mistakenly connected to the system ground. Confirm that the ground wire of the external device is connected to Isolated GND instead of GND

After installing multiple cards, check if the BIOS has allocated sufficient IRQ due to slow system startup, insufficient blue screen IRQ resources, or conflicting driver versions; Uninstall the old driver and reinstall the latest version

Unable to open device node under Linux. Main device number conflict or node not created. Execute mknod manual creation or rerun installation script to specify different main device numbers

Typical application cases and programming tips

Case 1: A railway signal system uses cPCI-3544 to connect 8 intelligent track sensors (RS-485), with each sensor approximately 500 meters apart. Select 2 3544 cards, set each port to RS-485 mode, only enable terminal resistors on the sensor side at both ends of the bus, and turn off the middle node. Each port is isolated independently to avoid communication interruption caused by ground potential difference of different sensors.

Case 2: A device debugging platform uses cPCI-3534, with three RS-232 ports connected to PLC programming port, touch screen, and barcode scanner, and an isolated RS-422 port connected to a remote frequency converter. All ports are working properly, please note that the isolation ground of Port D is separately connected to the frequency converter signal ground.

Programming tip: In Windows, the ports of these modules are considered standard COM ports and can be used with APIs such as CreateFile ("COMx"), AKS ommState, ReadFile/WriteFile, etc; In Linux, use standard POSIX functions such as open ("/dev/ttySx") and tcsetattr. The example code can be found in the Sample directory on the driver CD.