
Applied Micro Circuits Corporation
6195 Lusk Blvd., San Diego, CA 92121 (619) 450-9333
7-8
PCI CONTROLLER
S5933
DEVICE SPECIFICATION
7.5
EXPANSION BIOS ROMS
This section provides an example of a typical PC-
compatible expansion BIOS ROM. Address offsets
0040h through 007Fh represent the portion of the
external nv memory used to boot-load the S5933
controller. Whether the expansion ROM is intended
to be executable code is determined by the contents
of the first three locations (starting at offset 0h) and a
byte checksum over the defined length. The defined
length is specified in the byte at address offset
0002h. Table 7-2 lists each field location by its ad-
dress offset, its length, its value, and description.
Table 7-2. PC Compatible Expansion ROM
Byte
Binary
Offset
Length
Value
Description
Example
0h
1
55h
BIOS ROM signature byte 1
55h
1h
1
AAh
BIOS ROM signature byte 2
AAh
2h
1
var.
Length in multiples of 512 bytes
01h
3h
4
var.
Entry point for INIT function.
7h-17h
17h
var.
Reserved (application unique data)
18h-19h
2
var.
Pointer to PCI Data Structure
(see Table 7-3)
20h-3Fh
32h
var
user-defined
The following represents the boot-load image for the S5933 controller’s PCI configuration register :
40h
2
[your vendor ID]
(see Section 4.1)
1234h
42h
2
[your device ID]
(see Section 4.2)
5678h
44h
1
not used
xxh
45h
1
[Bus Master Config.] (see Section 11.3.1)
80h
46h
2
not used
xxxxh
48h
1
[your revision ID]
(see Section 4.5)
00h
49h
3
[your class code]
(see Section 4.6)
FF0000h
4Ch
1
not used
xxh
4Dh
1
[your latency timer #] (see Section 4.8)
00h
4Eh
1
[your header type]
(see Section 4.9)
00h
4Fh
1
[self-test if desired]
(see Section 4.10)
80h or 00h
50h
1
C0h, C1h or C2h
(required, see Section 4.11
and Table 7-1)
C0h, C1h or C2h
51h
1
FFh
(required per Table 7-1)
FFh
52h
1
E8h
(required per Table 7-1)
E8h
53h
1
10h
(required per Table 7-1)
10h
54h
4
[base addr. #1]
(see Section 4.11)
00000000h
58h
4
[base addr. #2]
"
00000000h
5Ch
4
[base addr. #3]
"
00000000h
60h
4
[base addr. #4]
"
00000000h
64h
4
[base addr. #5]
"
00000000h