Specifications

Table D–2 Memory Map, Typical Conﬁguration

Address Range (Hex) Function Size Shadow Cache WP

0010 0000–01FF FFFF Extended memory 63 MB No Yes No

000F 0000–000F FFFF System BIOS 64 KB Yes Yes Yes

000E 8000–000E FFFF Reserved system resources

32 KB No Yes Yes

000E 0000–000E 7FFF On-board video BIOS

extension

32 KB No Yes Yes

000D 0000–000D FFFF Terminal multiplexer 64 KB No Yes Yes

000C 8000–000C FFFF Adaptec SCSI host adapter 32 KB No Yes Yes

000C 2000–000C 7FFF Available for options 24 KB No Yes Yes

000C 0000–000C 1FFF 3Com 3C503 Ethernet 8 KB No Yes Yes

000A 0000–000B FFFF Video RAM 128 KB No Yes Yes

0000 0000–0009 FFFF Base memory 640 KB No Yes Yes

Write protected (not cached in the Intel 486).

Used only before operating system boot.

Table D–3 I/O Address Map

Range (Hex) Function

0000–000F ISP DMA controller one

0020–0021 ISP interrupt controller one

0026 MECA and CLASIC conﬁguration index

0027 MECA and CLASIC conﬁguration data

0040–0043 IPS timer one

0048–004B ISP timer two

0060 Keyboard data

0061 ISP NMI

0064 Keyboard command/status

0070 (bit 7) ISP enable NMI

0070 (bits 6–0) Real-time clock address

0071 Real-time clock data

(continued on next page)

D–2 Device Mapping