ADLINK Technology LittleBoard 735, Reference Manual

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Chapter 4 BIOS Setup
42 Reference Manual LittleBoard 735
5. Use the <Enter> key to select the screen menus listed in the Opening BIOS screen.
PCI-ISA Bridge Mapping
The LittleBoard 735 supports ISA bus based modules with an on-board PCI-ISA bridge. The PCI-ISA
bridge optionally maps the following resources to ISA based modules:
•
Memory
•
I/O Ports
•
IRQs
•
DMA Channels
The LittleBoard 735 system BIOS maps the above resources based on information provided in the BIOS
Setup screens. By default, only some of the I/O ports are mapped to ISA modules and any memory, IRQs or
DMA channels to be mapped to ISA modules must be explicitly specified by the user in the BIOS Setup
screens.
The IRQs and DMA channels are mapped with the “PCIPnP/IRQx” fields in BIOS setup (where x specifies
the IRQ number.) The IRQs 3, 4, 5, 7, 9, 10, 11, 14, and 15 can be mapped to ISA based modules by
changing the default setting for these IRQs from “Available” to “Reserved”.
ISA I/O ports, Memory, and DMA channels can be mapped to ISA modules on the “Boot/Boot Settings
Configuration” BIOS setup screen. Six I/O port “windows” and four memory “windows” are available for
mapping I/O Port or Memory regions to ISA modules by specifying the window length and base address.
By default, the following I/O port windows are mapped to ISA modules:
•
200-240h
•
240-260h
•
279h
•
300-340h
•
340-360h
•
A79h
By default, no memory windows are mapped to ISA modules.
Any of the DMA channels 0, 1, 2, 3, 5, 6, 7 can be mapped to ISA modules by changing the default setting
of “LPC Bridge” to “ISA Bridge”.
For example, to configure an ISA Soundblaster PnP card with resources 220/5/1/5 (Port/IRQ/DMA/DMA)
so that the Soundblaster would work in Windows XP, the following BIOS Setup changes would be required:
•
ISA I/O Ports – no changes necessary. 220h is already mapped to ISA by default.
•
IRQ – set IRQ5 to “Reserved” in BIOS Setup. See the paragraph above on mapping IRQs.
•
DMA1 and DMA5 – set DMA Channels 1 and 5 to “ISA Bridge” in BIOS Setup. See paragraph above
on mapping DMA Channels.
NOTE
The serial console port is not hardware protected, and is not listed in the COM table
within BIOS Setup. Diagnostic software that probes hardware addresses may cause a
loss or failure of the serial console functions.
NOTE 279h and A79 are the ISA PnP ports used by the BIOS and an OS that supports this
feature to recognize ISA PnP (Plug and Play) cards.