Microsoft KB Archive/89970

= How to Determine Interrupt, I/O, and DMA Channel Conflicts =

Article ID: 89970

Article Last Modified on 11/14/2003

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APPLIES TO


 * Microsoft Windows Sound System 1.0
 * Microsoft Windows Sound System 1.0a
 * Microsoft Windows Sound System 2.0

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This article was previously published under Q89970



SUMMARY
This article covers the valid ranges and some procedures for determining the right I/O address, interrupt, and direct memory access (DMA) channel for the Windows Sound System card.



Choosing the Correct I/O Address
The Windows Sound System card occupies two I/O address ranges: one is for the Yamaha OPL3 synthesis chip, and the other is for the Codec chip. Address range 0x388- 0x38b is always reserved for the OPL3 chip, whereas the Codec chip uses one of the following ranges (depending on the jumper settings on the board):   0x530-0x537 0x604-0x60c 0xe80-0xe87 0xf40-0xf47 The default I/O address is 0x530. To configure the I/O address after Windows Sound System is installed:


 * 1) Run Control Panel.
 * 2) Choose the Drivers icon.
 * 3) Select Microsoft Windows Sound System.
 * 4) Choose the Setup button.

If you see one or more of the following symptoms, there is likely an I/O address conflict with the Windows Sound System and another card:


 * The Windows Sound System driver displays an error saying it can't find a card.
 * The Windows Sound System driver displays an error saying that the card is not responding correctly.
 * FM synthesis does not work correctly.
 * Windows Sound System does not play any sounds.
 * Another card in your system does not work.
 * Windows does not start.
 * Windows stops responding (hangs).
 * Your computer does not start.

If the I/O port you have chosen is not working, the best way to find a new I/O port address is to remove the Windows Sound System board and rerun Setup using the following procedure. Setup looks for available I/O ports, and recommends the correct jumper settings. While Setup can detect available I/O port addresses, it may misjudge. In this case, you should consult the documentation for your other cards, or experiment with jumper settings.

To test for the correct I/O port, do the following:


 * 1) Turn the computer off and remove the Windows Sound System board.
 * 2) Restart the computer and start Windows.
 * 3) Run Windows Sound System Setup.
 * 4) Choose Continue twice to get to the Microsoft Windows Sound System Setup dialog box.
 * 5) Choose the Board button.
 * 6) Choose the Auto button.
 * 7) Note the jumper settings Setup suggests.
 * 8) Choose Continue, then exit Windows.
 * 9) Turn off the computer and change the jumper settings as suggested by Setup.

Choosing the Correct Interrupt
The Windows Sound System board uses Interrupts 7, 9, 10, and 11. Interrupts 10 and 11 are available only if the board is plugged into a 16-bit slot. Interrupt 11 is the default.

If you see one or more of the following symptoms, there is likely an IRQ conflict:


 * The first .25 seconds of sound repeats continuously.
 * The other card does not function correctly.
 * Windows stops responding (hangs).

The only way to find a new interrupt is to experiment. Sometimes the Windows Sound System card is able to positively identify an occupied IRQ and can prevent you from selecting this interrupt. Some cards, notably network cards, fool the Windows Sound System detection, and it can't tell what interrupt the other card is using.

Try the following procedure:

 Restart the computer, but do NOT start Windows. Insert Windows Sound System Disk #1 into your floppy disk drive. From the MS-DOS prompt, run the Windows Sound System Setup program by typing the following:



where is the letter of your floppy disk drive. Choose OK and follow the instructions on your screen. When Setup prompts you, remove the Windows Sound System driver. When Windows and Setup run again (automatically), choose Custom Board Setup.</li> Change the IRQ setting.</li> Restart Windows to activate the Windows Sound System driver.</li></ol>

Choosing the Correct DMA Channel
The Windows Sound System board uses DMA channels 0, 1, and 3. DMA channel 0 is only available if the card is plugged into a 16-bit slot, and is the default.

If you see one or more of the following symptoms, there is likely a DMA conflict:


 * The sound stops playing as soon as another device uses the DMA channel. For example, if there is a DMA conflict with a disk drive, then the sound stops as soon as the drive is accessed. The sound may continue playing but play the wrong data.
 * The other card won't function correctly.
 * Windows stops responding (hangs).

The only way to find a new DMA channel is by experimentation or examination of the hardware interrupts.

Keywords: KB89970

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