Requirements for PCI Audio Devices

For audio devices that connect to the PCI bus, the following requirements apply.

17. PCI device conforms to PCI 2.1 and additional PC 98 requirements
Required

If the device uses PCI, it must meet the requirements defined in the “PCI” chapter in Part 3 of this guide, including requirements for providing a Subsystem ID and Subsystem Vendor ID and for complying with PCI 2.1.

18. PCI device supports initiator, target, and block transfer
Required

For complete implementation details, see PCI 2.1.

Full-duplex audio sample transport must be supported using separate PCI bus mastering hardware for playback and capture sample streams.

It is desirable for sample transport mastering hardware to support burst capabilities in order to read or write multiple samples within the same PCI bus transaction. This will lessen the impact of sample transport on other agents in the system, which will have a positive effect on the system’s responsiveness.

19. PCI audio components use a suitable configuration scheme if using ISA resources
Required

If a PCI audio device requires the use of ISA resources such as IRQs or DMA, it must configure these resources in a way that meets the following objectives:

  • Any resource enabled while Windows or an MS-DOS window is active must be reported to the Windows Device Manager. Conversely, if a PCI device uses ISA resources in MS-DOS mode that do not appear in the Configuration Manager, then the device must disable these resources before Windows restarts.

  • The ISA resources allocated by a PCI device must be used only for MS-DOS mode or for applications running in an MS-DOS window. Windows-based applications must not require the use of ISA resources.

Two acceptable means for achieving these objectives are as follows:

  • For a PCI audio device on the system board, the BIOS can configure the ISA resources and present a device node to the operating system. The operating system can then understand and reconfigure the ISA resources.

  • For a PCI audio device present in an add-on card, the device does not use any ISA resources while running Windows or an MS-DOS window. Only when the user enters MS-DOS mode does the ISA resource become enabled.

PCI devices on the system board do not have to provide relocatable I/O addresses for the following legacy I/O registers:

  • Sound Blaster (220h to 22Fh)

  • FM synthesis (388h to 38Bh)

  • MPU 401 (330h to 331h)

  • Windows Sound System (WSS) compatible (534h to 537h)

  • Game port (200 to 207h)

20. PCI device is digital ready

Required

In order to transfer digital audio to USB or IEEE 1394 devices, all digital audio data created in the PC must be available to the operating system for mixing and streaming. All PCI audio devices must be able to route the final mix of all digital audio data created or processed on-chip to the host using bus master transfers.

Support for capture and inclusion of internal analog resources in the final mix is desirable but not required. CD-ROM drives that support direct reading of Red Book data through the primary interface are strongly recommended.

For example, a PCI audio device provides HRTF 3-D filtering and wave-table synthesis. After mixing all of the separate 3-D sources and wave-table channels down to a single stereo stream, the device transfers the data to host memory.