Viglen VIG520S, Руководство пользователя

Страница: 42 / 86

41 of 85
BIOS Flash Memory Organisation
The 2-Mbit flash component is organised as 256 KB x 8 bits and is divided into areas
as described in Table 9. The table shows the addresses in the ROM image in
normal mode (the addresses change in BIOS Recovery Mode).
Table 9: Typical Flash Memory Organization
Address (Hex) Size Description
FFFFC000 –
FFFFFFFF 16 KB Boot Block
FFFFA000 –
FFFFBFFF 8 KB Vital Product Data (VPD) Extended
System Configuration Data (ESCD) (DMI
configuration data / Plug and Play data)
FFFF9000 -
FFFF9FFF 4 KB Used by BIOS (e.g., for Event Logging)
FFFC0000 -
FFFF7FFF 228
KB Main BIOS Block
Plug and Play: PCI Auto-configuration
The BIOS automatically configures PCI devices and Plug and Play devices. PCI
devices may be onboard or add-in cards. Plug and Play devices are ISA add-in
cards built to meet the Plug and Play specification. Auto-configuration lets a user
insert or remove PCI or Plug and Play cards without having to configure the system.
When a user turns on the system after adding a PCI or Plug and Play card, the BIOS
automatically configures interrupts, the I/O space, and other system resources. Any
interrupts set to Available in Setup are considered to be available for use by the add-
in card.
PCI interrupts are distributed to available ISA interrupts that have not been assigned
to an ISA card or to system resources. The assignment of PCI interrupts to ISA
IRQs is non-deterministic. PCI devices can share an interrupt, but an ISA device
cannot share an interrupt allocated to PCI or to another ISA device. Auto-
configuration information is stored in the extended system configuration data (ESCD)
format.