NEC SP B-Series Cmos Memory/Real-Time Clock Battery, DMA/IRQ Settings, Plug and Play Support

System Memory Map

Memory Address	Size	Function
100000-18000000	383 MB	Extended memory
E8000-FFFFF	96 KB	System BIOS
E0000-E7FFF	32 KB	System BIOS (available as
		UMB)
C8000-DFFFF	96 KB	Available high DOS memory
		(open to ISA and PCI bus)
A0000-C7FFF	160 KB	Video memory and BIOS
00000-9FFFF	640 KB	Conventional memory

Plug and Play Support

The system comes with Plug and Play BIOS technology. Plug and Play eliminates complicated setup procedures for installing Plug and Play expansion boards.

To add a Plug and Play expansion board, simply power off the system, install the board, and power on the system. There are no jumpers to set and no system resource conflicts to resolve. Plug and Play automatically configures the board for the system. The system also supports non-Plug and Play boards.

Plug and Play is controlled by the Plug and Play BIOS and the system’s operating system. The Plug and Play BIOS is stored in the Flash EPROM on the system board.

The Plug and Play BIOS adds several steps to the POST process. During POST, the Plug and Play evaluates the configuration of installed boards and assigns available system resources to the devices. On completion of Plug and Play POST, the operating system checks to see if there are any additional resources required, then assigns available resources to the devices.

CMOS Memory/Real-Time Clock Battery

The 82371EB PCI ISA IDE Xcelerator (PIIX4E) on the system board stores system information in non-volatile CMOS memory. The chip also contains the system’s real-time clock. Both are maintained by a 3-volt coin cell lithium battery on the system board. The battery is replaceable.

DMA/IRQ Settings

The system automatically configures, with minimal user intervention, interrupt requests (IRQ), direct memory access (DMA) channels, and other parameters when adding PCI boards.

The following tables list system IRQ and DMA default settings.

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