M-AUDIO Dman 2044 - Manual (Page 29)

the full benefits of PnP, you will need a PnP-compliant operating system
(Windows 95 for example), motherboard, system BIOS, and interface
card(s). Older non-compliant ISA expansion cards (called “legacy”
cards) will function in PnP systems as well, but will still require some
manual configuration. The PCI bus architecture by default includes a
PnP capability and there is no such thing as a “legacy PCI card.”
Think of PnP as digital aspirin. Device configuration occurs transparent-
ly in an all-PnP environment. At bootup, the system BIOS and the oper-
ating system detect hardware and attempt to allocate resources, eliminat-
ing the need to manually configure resources such as IRQ’s, I/O ports,
DMA channels and memory space. Peripheral interface cards are put “to
sleep" by the system and are then individually queried regarding which
resources are programmable and over what ranges they may be pro-
grammed. The PnP BIOS will then build a conflict-free resource assign-
ment list for all PnP devices, update a stored working-configuration
database, configure and activate the peripheral devices, then start the
operating system (Windows 95 for example) which loads the device dri-
vers with the stored configuration information.
PCI Interrupts
The PCI bus connectors (the slots in which you install PCI cards) have
four interrupt lines wired to each of them (interrupts A, B, C, and D).
The motherboard allows PCI cards to share interrupts, and also provides
a way to assign each interrupt to a specific IRQ on the motherboard (the
same IRQ’s available to devices in ISA slots). This interrupt assignment
(sometimes called “interrupt steering”) is done by either the system BIOS
or the operating system.
Recognizing an Interrupt Conflict
Typically it is ISA “legacy” (non-PnP) cards that cause interrupt conflicts
with PCI cards. This is because the system BIOS and the operating sys-
tem have no way to query legacy cards to find out what resources they
are currently assigned to. Fortunately, Windows 95 and most system
BIOS’s provide a way to reserve IRQ’s for the use of legacy cards. The
PnP system is then aware of the “keep out” zones and avoids configur-
ing PnP interface cards to those reserved resources.
When your DMAN 2044 card’s driver is not able to properly install itself,
you should first check what resources it is using, particularly the IRQ.
This is done from the Windows 95 Device Manager. First press the
Windows Start button, then select Settings | Control Panel | System. This
should open the System Properties dialog box. Click on the Device
Manager tab to reveal the Windows 95 Device Manager. Next to the line
29