Expansion rom base address, Capabilities pointer, Register: 0x34 – Avago Technologies LSI53C1030 User Manual
Page 100
4-14
PCI Host Register Description
Version 2.2
Copyright © 2001, 2002, 2003 by LSI Logic Corporation. All rights reserved.
Register: 0x30–0x33
Expansion ROM Base Address
Read/Write
This four-byte register contains the base address and size information for
the expansion ROM.
Expansion ROM Base Address
[31:11]
These bits correspond to the upper 21 bits of the expan-
sion ROM base address. The host system detects the
size of the external memory by first writing 0xFFFFFFFF
to this register and then reading the register back. The
LSI53C1030 responds with zeros in all don’t care loca-
tions. The least significant one (1) that remains repre-
sents the binary version of the external memory size. For
example, to indicate an external memory size of
32 Kbytes, this register returns ones in the upper 17 bits
when written with 0xFFFFFFFF and read back.
Reserved
[10:1]
This field is reserved.
Expansion ROM Enable
0
This bit controls if the device accepts accesses to its
expansion ROM. Setting this bit enables address decod-
ing. Depending on the system configuration, the device
can optionally use an expansion ROM. Note that to
access the expansion ROM, the user must also set bit 1
in the PCI
register.
Register: 0x34
Capabilities Pointer
Read Only
31
11 10
1
0
Expansion ROM Base Address
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7
0
Capabilities Pointer
X
X
X
X
X
X
X
X