Serial Products Troubleshooting

Troubleshooting - AT RS-232 or AT RS-485 Windows 3.x

The following procedure is a standard means of isolating and solving serial problems:

If there are any ni-pnp errors, use the following procedure to troubleshoot them:
- The ni-pnp.exe program should be located in the root directory of your boot drive, usually C:\. It should be run from your autoexec.bat file, so that ni-pnp executes every time your system is started. ni-pnp normally produces very little output when it is run, displaying only the name of each National Instruments interface board it detects. Most errors that ni-pnp might detect are handled transparently. If ni-pnp finds an error from which it cannot recover, it displays a message and describes the best method for fixing the problem.
- Some possible problems that ni-pnp might report include boards with unassigned resources and boards for which resource conflicts exist. If ni-pnp encounters a board with no assigned resources, it displays the following message:
  
  This interface has no assigned resources.
  If you get this message, you must run the serial software configuration utility and assign resources to the board.
- If ni-pnp detects an I/O address conflict, it displays the following message:
  
  I/O Address Conflict.
  If you get this message, you must run the serial software configuration utility and change the base I/O address for the board.
- You can run ni-pnp in a verbose output mode. In this mode, ni-pnp displays more information about each interface, including its assigned resources. To run ni-pnp in verbose mode, change to the directory which contains ni-pnp.exe. This is the root of the boot drive (usually C:\). Run ni-pnp with the verbose output flag by typing ni-pnp /v.
- Another, more serious error can also occur on systems that are not Plug and Play ready. Since ni-pnp must assign resources to the boards, it must first perform the Plug and Play ISA isolation sequence. The isolation sequence is a method by which all Plug and Play boards can be detected. It is possible, although rare, that this isolation sequence could lock up your computer. If this occurs, restart your computer. ni-pnp will then detect that your computer was locked up and display an error message describing the problem. ni-pnp can enter a fail-safe detection mode where it records each I/O port before testing that port. If your computer locks up while testing a port in this mode, ni-pnp will exclude that I/O port from future testing. If you know that you do not have any National Instruments Plug and Play boards in your system, you can configure ni-pnp so that it does not attempt to detect any Plug and Play boards. ni-pnp will prompt you to choose between entering the fail-safe mode or disabling the detection of Plug and Play boards.

Troubleshooting serdiag Error Messages:

A resource conflict occurs if an AT serial port is assigned a resource that is being used by some other device in the system. Most serdiag errors are caused by resource conflicts. Your system will not work properly if a resource conflict exists, so you should resolve all conflicts before using your AT serial board.
- You must configure each AT serial port to use one unique ISA interrupt level. An interrupt conflict occurs if another plug-in board (or a device on the computer motherboard) is configured to use the same ISA interrupt level. To resolve an interrupt conflict, you must do one of the following:
  - Change the interrupt level used by the AT serial port.
  - Change the interrupt level used by the other plug-in board.
  - Configure the AT serial port not to use interrupts. (This solution is not recommended and will not work if you are using Windows.)
- Each AT serial port uses 8 contiguous I/O addresses. The lowest address used by the AT serial port is the base address. For example, if the base address of an AT serial port is 3E8 (hex), the AT serial port uses all 8 addresses in the range 3E8 through 3EF (hex). An I/O address range conflict exists if another plug-in board (or a device on the computer motherboard) is configured to use any address in the I/O address range used by any of the ports on the AT serial board. To resolve an I/O range conflict, do one of the following:
  - Change the base address used by the conflicting AT serial port.
  - Change the I/O range used by the other plug-in board.
- Use the following steps to troubleshoot serdiag error messages.
  1. Verify that all serial cables are disconnected. If any serial cables are connected to your AT serial board, disconnect the cables and run serdiag again.
  2. Note which error message serdiag displays. The most common error messages are as follows:
    
    <<< Base I/O Address Conflict >>> <<< Interrupt Level Conflict >>> <<< Error Reading NI-PNP.INI >>>
    If the error is in reading ni-pnp.ini, try reinstalling the software and then run serdiag again. If a resource conflict exists, write down the exact resource tested. For example, if an IRQ resource conflict exists, note which IRQ setting was tested.
  3. Run the ni-pnp utility in verbose mode to determine what software configures the Plug and Play circuitry of your AT serial board.
  4. If ni-pnp reports Intel Configuration Manager version x.xx Found, refer to the next section. Otherwise, continue with step 5.
  5. Run SerialConf to change the resources used by your AT serial board. If serdiag indicated that your AT serial board failed because of a base I/O address conflict, change the base I/O address location of the conflicting port in SerialConf. Similarly, if serdiag indicated an interrupt level conflict, change the IRQ setting in SerialConf.
  6. Save the new SerialConf settings.
  7. Reboot the computer.
  8. Run serdiag again and go back to step 1.
If a resource conflict exists, the Intel software does not have the resource information for some legacy ISA board in your system. It is therefore free to assign to the AT serial board some resource that is already used. To resolve the resource conflict, complete the following steps:
1. Run the Intel ISA Configuration Utility (ICU).
2. Modify the configuration of the AT serial board. For example, if serdiag error message noted in step 2 above indicates an interrupt conflict on interrupt level 11, configure that AT serial board to use another available interrupt level.
3. Try to determine which other plug-in board is using the conflicting resource. Consult the documentation that came with the other plug-in boards.
4. Depending on whether you can determine which other plug-in board is using the conflicting resource, complete the following steps:
5. Save the changes and exit the ICU.
6. Reboot the computer and run serdiag again. If you still have problems after completing these steps, you may have other conflicts to resolve. Repeat these steps until you have resolved all of the conflicts.