Appendix A
System Resourcen
Kontron User's Guide PC/104-520
47
A.4 Memory Map
The first 640 kB of DRAM are used as main memory. Using DOS, you can address 1 MB of memory directly.
Memory area above 1 MB (high memory, extended memory) is accessed under DOS via special drivers such
as HIMEM.SYS and EMM386.EXE, which are part of the operating system. Please refer to the operating
system documentation or special textbooks for information about HIMEM.SYS and EMM386.EXE.
Other operating systems (Linux or Windows versions) allow you to address the full memory area directly.
Upper Memory
Use
Available
Comment
A0000h – BFFFFh
VGA Memory
No
Mainly used by graphic adapter cards
C0000h – CBFFFh
VGA BIOS
No
Used by onboard VGA ROM
CC000h – E1FFFh
Yes
Free for ISA bus or shadow RAM in standard con-
figurations
E2000h – FFFFFh
System BIOS
No
Fixed
A.5 PCI Devices
All devices follow the Peripheral Component Interconnect 2.1 or 2.2 (PCI 2.1/2.2) specification. The BIOS
and OS control memory and I/O resources. Please see the PCI 2.1/2.2 specification for details.
PCI Device (IDSEL)
PCI IRQ
REQ / GNT
Comment
Onboard Host Bridge
None
Integrated in SC520
Onboard Graphic Controller
INTA
REQ0/GNT0
External (SM712)
Onboard Network Controller
INTB
REQ1/GNT1
External i82551ER
